dn01141526_6_SIGTRAN

00055783-1.0 Nokia Siemens Networks GSM/EDGE BSS, rel.RG10(BSS), operating documentation, issue 02 Signalling Transport over IP (M3UA and IUA) DN01141526 Issue 7-0 en # Nokia Siemens Networks 1 (81) Signalling Transport over IP (M3UA and IUA) The information in this document is subject to change without notice and describes only the product defined in the introduction of this documentation. This documentation is intended for the use of Nokia Siemens Networks customers only for the purposes of the agreement under which the document is submitted, and no part of it may be used, reproduced, modified or transmitted in any form or means without the prior written permission of Nokia Siemens Networks. The documentation has been prepared to be used by professional and properly trained personnel, and the customer assumes full responsibility when using it. Nokia Siemens Networks welcomes customer comments as part of the process of continuous development and improvement of the documentation. 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All rights reserved. 2 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en Contents Contents Contents 3 List of tables 5 List of figures 6 Summary of changes 7 1 1.1 1.1.1 1.1.2 1.2 1.3 1.4 1.5 2 2.1 2.1.1 2.2 2.2.1 2.3 2.4 2.5 3 3.1 4 5 6 7 8 9 10 10.1 10.2 11 11.1 11.2 Signalling transport over IP (M3UA and IUA) Association 10 SCTP multi-homing 11 SCTP stream 14 Association set 15 SGP - ASP communication 17 IPSP-IPSP communication 18 Signalling over IP statistics 19 Use of M3UA stack 23 SGP-ASP communication 23 Example of M3UA usage 25 IPSP-IPSP communication 26 Use of IPSP-IPSP example at the M3UA 27 Routing key and routing context 28 Signalling Point Management Cluster 29 Message structure of M3UA 30 Use of IUA 33 Message structure of IUA 34 9 Basic structures of M3UA network 37 Planning site configuration for signalling 41 Planning M3UA network 49 Creating M3UA configuration 51 Planning IUA network 57 Creating IUA configuration 59 Modifying Sigtran parameters 63 Modifying association set level parameters of M3UA Modifying SCTP association level parameters 66 Deleting IP signalling links 73 Deleting M3UA signalling links 73 Deleting IUA connections 73 63 DN01141526 Issue 7-0 en # Nokia Siemens Networks 3 (81) Signalling Transport over IP (M3UA and IUA) 12 12.1 12.2 12.3 12.4 12.5 Signalling transport over IP troubleshooting 75 IP signalling link activation fails 75 D-channel activation failed 77 SCTP association failed 79 Path of SCTP association failed 80 List of debugging commands in a failure case 80 4 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en Summary of suggested parameter sets 68 DN01141526 Issue 7-0 en # Nokia Siemens Networks 5 (81) .List of tables List of tables Table 1. Message structure of IUA Figure 16. Figure 9. Figure 6. Figure 4. Figure 2. An example of an M3UA network with SCCP relay function Figure 18. Association between two network elements 11 12 SCTP retransmission when both primary and secondary paths fail Symmetric network layout Asymmetric network layout 13 13 15 Example of an IP type SS7 signalling link Association set 16 An example of SGP-ASP communication 18 An example of a basic IPSP-IPSP configuration with a point to point connection inside the IP network 19 An example of SGP-ASP communication 23 Figure 10. Figure 7.Signalling Transport over IP (M3UA and IUA) List of figures Figure 1. Basic example of a network that uses IP Figure 17. IUA protocol 33 35 37 38 32 30 27 Figure 15. Avoiding number of point-to-point IP route 43 6 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . An example of combined Signalling Gateway and IPSP-IPSP Figure 12. An example of a Signalling Gateway between two network elements in different protocols 25 Figure 11. An example of Signalling Point Management Cluster Figure 13. Message structure of M3UA Figure 14. Figure 8. Figure 3. Figure 5. because it contained only redundant information. . Command Group (Q6) for IPv6 does not exist anymore. IP configuration for IPv4 and IPv6 is now managed with one MML command (QR).Summary of changes Summary of changes Changes between document issues are cumulative. the latest document issue contains all changes made to previous issues. Therefore. DN01141526 Issue 7-0 en # Nokia Siemens Networks 7 (81) . A network Interface configuration (QRA) is now a mandatory operation before any IP address can be added to a unit network Interface (QRN). The changes have influence on the chapters Planning site configuration and Signalling transport over IP Troubleshooting. The Redundant IP address backup interface can be configured now with one command (QRN). Changes made between issues 5–0 and 4-4 New feature 'Interrogate Average CPU load' added. Changes made between issues 7–0 and 6-0 . . Figure 'Message structure of IUA' corrected. Changes made between issues 6–0 and 5-0 Editorial changes and link corrections. The example 'Configuring asymmetric SCTP multi-homing' is removed from chapter 'Planning site configuration for signalling'. Link corrections. Signalling Transport over IP (M3UA and IUA) Links to MML commands have been improved in all chapters. 8 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . SS7 signalling can also be received over ATM interface using the SS7 Message Transfer Part (MTP) to provide transport. provision is made for protocol elements that enable a seamless operation of the MTP3-User peers in the SS7 and IP domains. This can be achieved by using modified SCTP transport parameters. It is very important especially when the SCTP parameters in use have been defined.921 User Adaptation Layer (IUA). IUA is a protocol supporting the transport of Q. Both protocols are to be used between a Signalling Gateway (SG) and a Media Gateway Controller (MGC). In an IP signalling network planning phase. The IUA adaptation enables an MSS controlling a Private Automatic Branch Exchange (PBX) even if the MSS does not have Pulse Code Modulation (PCM) connectivity.Signalling transport over IP (M3UA and IUA) 1 Signalling transport over IP (M3UA and IUA) The information in this document relates to DX200 and IPA 2800–based products. Also. ISDN user part (ISUP) and Signalling Connection Control Part SCCP messages) over IP using the services of the Stream Control Transmission Protocol (SCTP). M3UA is a protocol for supporting the transport of any SS7 MTP3-User signalling (for example. It uses the services of the SCTP. It is assumed that the SG receives SS7 signalling or Link Access Procedure on the D-channel (LAPD) signalling over a standard E1 or T1 interface.921 user signalling over IP. a used WAN and/or transmission network capacity and quality of service items shall be taken into account. DN01141526 Issue 7-0 en # Nokia Siemens Networks 9 (81) . Signalling transport over IP (SIGTRAN) contains several user adaptation layers. two of which are described here: the MTP3 User Adaptation Layer (M3UA) and the Q. Signalling transport over IP offers almost similar quality of service as TDMbased signalling connection. If one of those address parameters is different. the Client tries to establish an association to the secondary destination IP address. it means that a new association should be established. SCTP can use multi-homed connection but a TCP does not know that kind of architecture.1 Association An SCTP association is a relationship between two communicating peers. the retransmission parameters of the SCTP must be adjusted so that the criteria will be met also when using the IP-net. During the association establishing phase the Client normally sends an SCTP initialize message to the primary destination IP address. If both communicating peers are based on our system. When readjusting SCTP retransmission parameters you need to take into account the method of implementation of the IP-net (either LAN or WAN) as well as the quality of service it provides. The Client peer establishes an association. If the primary destination IP address does not response to anything. An association can have several logical paths (source and destination IP address pair). the SCTP has been used in implementation as the data link layer. The system supports two destination IP addresses.Signalling Transport over IP (M3UA and IUA) 1. an SCTP association is much more fault tolerant than a TCP connection. that kind of connection is called multi-homed connection. 10 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . the system changes a configuration so that signalling traffic is running over the primary network and the secondary network is running a backup mode. The most crucial criteria of these is the transit time delay. and list of destination IP addresses. For the above mentioned Signalling adaptations to work as solidly as their examples (Q. destination port number. To meet the traditional quality requirements when using the SCTP. the SCTP association has been established between two signalling units by client peer. Application of an SCTP is establishing and maintaining an association. primary destination IP address and secondary destination IP address.921 and Q. When the network failure in the primary network is over. The SCTP association uses the following address parameters: source port number. For this reason. Configuration of an SCTP association is done in the application level.704). SCTP offers similar certification capacities as can be expected when using a traditional TDM connection. list of source IP addresses. a host is called multi-homed if it can be addressed by multiple IP addresses. If something unexpected happens in the primary path. The SCTP implementation supports two paths per association. If a network failure occurs in the primary network. SCTP resends unacknowledged data through the secondary path automatically. for example. the SCTP stack takes care of all the details. each of which has to be configured to work in a different sub-network. It is not used.1 SCTP multi-homing In the IP terminology. Association between two network elements 1. the host also needs to support multiple network interfaces. The following figure describes how the SCTP retransmission works when both the DN01141526 Issue 7-0 en # Nokia Siemens Networks 11 (81) . The SCTP multihoming is used only for recovering from network failures. The SCTP monitors a condition of the secondary path all the time by using a heartbeat message. The SCTP association works normally so that data runs through the primary path and SCTP heartbeat runs through the secondary path. Normally data is sent through the primary path. In this case. for load balancing.1.Signalling transport over IP (M3UA and IUA) Association ESB20 MSS SIGU signalling end point ESB20 Figure 1. The application cannot see which path is used and it does not affect sending of data traffic in application level either. the SCTP usually has an alternative path available. To make full use of the SCTP multi-homing. End Point A Primary Path 300ms 300ms 500ms 500ms Secondary Path Primary Path Secondary Path Abort End Point B Primary path Unavailable Figure 2.max. . Retransmission time-out. It starts the retransmission timer and starts to wait for the SACK message from the remote peer. . If the remote peer does not send any SACK before the retransmission timer expires again.max value. For more information about SCTP parameters. The retransmission procedure starts always the same way. the SCTP starts using the value of the RTO. RTO.max 500 ms Path.retrans 4 . the sending peer resends data packets through the primary path and doubled the value of the retransmission timer. SCTP retransmission when both primary and secondary paths fail The SCTP sends data first through the primary path.max.retrans 2 Assoc. the first retransmission is done through the secondary path. If new retransmission timer value is greater than the RTO.max parameter as a new retransmission timer. refer to chapter Modifying SCTP association level parameters. The maximum amount 12 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en .Signalling Transport over IP (M3UA and IUA) primary and the secondary paths failed. If both paths are totally out of order. If the retransmission timer expires. the remote peer does not send any SACK. The example above is based on the following SCTP parameters: . the SCTP re-sends data through the secondary path and restarts the retransmission timer again by using the same value as before.min 300 ms RTO. Sending peers try to resend data as many times as they are allowed to try. max. There are two types of SCTP multi-homing. HOST A HOST B Figure 4. The SCTP ensures that none of the messages can get lost if only one path is broken at the same time. Symmetric network layout The first type is symmetric SCTP multi-homing where both peers have two or more external Ethernet interfaces available and connection is made between them.retrans parameter. Each signalling unit contains two Ethernet Interfaces in network element. Asymmetric network layout DN01141526 Issue 7-0 en # Nokia Siemens Networks 13 (81) . otherwise multi-homed connections do not work as expected. The SCTP can use both interfaces in such a way that one is working as a primary and the other one as a secondary path.Signalling transport over IP (M3UA and IUA) of retransmission per association is the same as the value of the assoc.retrans. the sending peer stops trying to resend data and closes an association by sending an ABORT message to remote peer. When error counter is equal to or greater than the value of assoc.max. HOST A HOST B Figure 3. Each Ethernet port should belong to a different subnetwork of the signalling unit. Signalling Transport over IP (M3UA and IUA) The second type is asymmetric multi-homing where a configuration also has two separate paths but Host A has only one Ethernet port in use. It is recommended to use multiple data streams. Alternatively. This additional address of Host A should be taken into account in the network configuration of the routers as well. In IUA implementation it is possible to use multiple outbound streams. If Host A is assigned to a second network. in that case the first data stream is always 1. multi-homing helps to avoid association loss. SCTP uses streaming for message ordering. then multi-homing does not help. Number of streams per association is 16 in the M3UA. Used number of outbound streams depends on SCTP applications because application should tag each of its outbound messages with a stream identifier. It is possible to configure with an association set parameter whether the data stream is 0 or 1. Stream is unidirectional. Each independently ordered message sequence is called a stream. 1. especially when only one SCTP association is in use between network elements. Outbound stream number 0 might be used for special purpose.1. Management messages are always sent to stream 0. For example in IUA and M3UA user adaptations are required that only management message is allowed to use a stream 0 and therefore the first data stream is 1. then the resiliency of the network can be improved. this can be avoided by using multiple associations. In that case the system is using lower number of streams automatically. The main purpose of the stream is to avoid so called head of line blocking situation. If the only Ethernet port of Host A or the gateway router where it is connected fails. in case of any kind of network failure. As a result of this modification. The maximum number is 64.2 SCTP stream SCTP provides multiple stream function within an SCTP association. In M3UA implementation it is possible to use multiple streams for data messages. Description of how asymmetric SCTP multi-homing configuration should be configured is described in the chapter Creation of SCTP configuration. which means that the number of outbound streams and the number of inbound streams can be different. The number of data streams can vary from one to thousands. There each D-channel uses own stream identifier so that within single association should be supported as many streams as D-channels are supporting. 14 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . except when remote end supports fewer streams than local end wants to use. an IP end point is a signalling unit. If more signalling capacity is needed between two network elements.Signalling transport over IP (M3UA and IUA) 1. In that way system resources can be used more efficiently. Example of an IP type SS7 signalling link Additionally. For example. you share the load among more than one computer units and at the same time make the signalling connection redundant. M3UA has been planned to work in such a system. One signalling unit can be connected to multiple association sets if the network element also needs to communicate with other peers. association MGW (server) MSS (client) ISU 0 ISU 1 ISU 2 ISU 3 association set / SS7 signalling link set SIGU 0 IP network SIGU 1 SIGU 2 SIGU 3 Figure 5. it is recommended that the signalling unit is only connected to one association set. In some case it might be DN01141526 Issue 7-0 en # Nokia Siemens Networks 15 (81) . In our system.2 Association set A system is based on a distributed architecture so that there are several computer units which can do same kinds of tasks. A network element may contain tens of signalling units. SCTP association is a point-to-point connection between two end points (see the following figure). it is assumed that each SCTP association is created to different signalling unit. signalling capacity can be increased by adding more SCTP associations to the association set. In this case. By using multiple signalling units in one association set (one association per signalling unit). if support of multiple SS7 networks is required in the network planning then more than one association set between two network elements must be created. when there is a multiple association set between two network elements. Association set Used load sharing method of the M3UA depends on a signalling traffic. On the M3UA. then SLS value is used for load sharing. for ordered messages. However. Up to 32 active associations can be used for a case where unordered messages are used. In case 16 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . when at least one SCTP association is active inside the association set. Unordered message mode is possible only with an interface where SCCP protocol class 0 has been used. traffic is shared to a maximum of 16 first activated SCTP associations.Signalling Transport over IP (M3UA and IUA) necessary to create multiple associations. Signalling route set Signalling link set Signalling link Association set Association Association Association Figure 6. for which the SLS is used for load sharing. That is not recommended but it is possible to do when the network planning has not been able to do in other way. If signalling traffic requires an ordered delivery. The state of a signalling link follows the state of the association set. which are connected to the same signalling unit. in the association set. the signalling link is active. That means that all signalling messages with same SLS are delivered through the same association inside the association set. each IP signalling link is associated with an association set consisting of up to 32 SCTP associations. 1. which can serve a specific routing key. When association failure is over. Each association inside an association set can be in the following states: . it is necessary to update the routing table of association set. DOWN-BY-USER SCTP_DOWN UP-PROCEEDING ASP-DOWN ASP-INACTIVE ASP-ACTIVE . DN01141526 Issue 7-0 en # Nokia Siemens Networks 17 (81) .Signalling transport over IP (M3UA and IUA) of association failure. DPC is used as a routing key at the solution.ASP communication Signalling Gateway process is a signalling agent that sends and receives telecom signalling traffic at the edge of IP network. As mentioned earlier. Framework Architecture for signalling transport. the content of association set routing table is required to be exactly the same as it was before the failure. Association set concept is only used in M3UA connections. ASP-SGP concept is described in the following figure. . .3 SGP . Note Association set is related to Nokia distributed architecture. Application server is a some kind of virtual database or call control element. and it is a Nokia Specific concept. SGP-ASP communication based on IP network as transportation. According to IETF-RFC 2719: Framework Architecture for Signaling Transport . Signalling Gateway as a signalling converter where TDM or ATM based signalling connection is terminated. . . 18 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . The other possibility is the dual-ended mode. since both peers exist in the IP domain.Signalling Transport over IP (M3UA and IUA) SEP/STP CAP/MAP/. where only one endpoint sends ASP management messages.4 IPSP-IPSP communication In case of IPSP-IPSP communication.. the services of a Signalling Gateway node are not needed.. The message exchange in an IPSP-IPSP connection is single-ended by default.. where both endpoints send ASP management messages. 1.. TCAP BICC/ISUP MTP3 MTP2 MTP1 SCCP BSSAP BICC/ISUP ASP CAP/MAP/. TCAP SCCP M3UA SCTP IPv4/IPv6 BSSAP SG MTP3 MTP2 MTP1 M3UA SCTP IPv4/IPv6 Figure 7. An example of SGP-ASP communication The example above describes the ASP-SGP connection in case of M3UA. A group of IPSPs form an Application server at both ends of the signalling connection. In the signalling unit level. if the congestion is affected due to the IP backbone or lack of CPU capacity. The Interrogate Average M3UA CPU Load. The SCTP statistics counters offer overall number of SCTP traffic in the signalling unit.Signalling transport over IP (M3UA and IUA) Applications Adaptation Layers SCTP Applications Adaptation Layers SCTP IP IP IPSP-IPSP Figure 8. OYQ MML command helps in dimensioning the network.5 Signalling over IP statistics IUA-specific statistics are not available yet. and therefore those counters are not so useful if one is interested only in the traffic of specific SCTP user adaptation. M3UA Association Set Measurement (295H/661) can be used to monitor M3UA traffic. The M3UA Association Set measurement can be started DN01141526 Issue 7-0 en # Nokia Siemens Networks 19 (81) . the Sigtran traffic can be monitored from the SCTP stack counters. The measurement measures M3UA traffic from M3UA layer and SCTP layer. Thus it helps to monitor. It also enables more efficient troubleshooting and network management. which is useful as there are capacity limits for the traffic. It gives information on traffic through put and quality of M3UA connections. to handle M3UA traffic. An example of a basic IPSP-IPSP configuration with a point to point connection inside the IP network 1. Those counters contain traffic from all SCTP user adaptations. The SCTP statistics counters are possible to see by using QRS. With the OYQ MML it is possible to monitor the amount of M3UA traffic that is handled by a signalling unit. Reports (Part 3). The SCTP layer counters give the operator more accurate information on the real load required for sending M3UA traffic through SCTP by including the number of retransmitted SCTP packets and SCTP header. For more information on the M3UA Association Set Measurement. Operating Instructions. Operating Instructions and NSS Statistics. M3UA layer counters tell the payload of the SCTP connection. Supported counters are the following: M3UA association set counters: Duration of M3UA association set has been unavailable Number of times M3UA association set has been unavailable M3UA association counters: Duration of M3UA association has been unavailable Number of times M3UA association has been unavailable Number of received packets on M3UA association Number of sent packets on M3UA association Number of octets received on M3UA association Number of octets sent on M3UA association SCTP counters used by M3UA: Number of SCTP packets received Number of SCTP packets sent Number of SCTP octets received 20 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . Measurement is configured by using common statistics interface T2 MML command group commands. Unavailability counters can be used for monitoring. From the counters of the SCTP layer. see NSS Statistics. the operator can retrace the traffic of the SCTP layer used by M3UA association.Signalling Transport over IP (M3UA and IUA) and stopped with the MML commands of the T2 command group. for example if the association is in ASP-INACTIVE state. see Section M3UA Association Set measurement report (661/295H) in NSS Statistics. DN01141526 Issue 7-0 en # Nokia Siemens Networks 21 (81) . The MTP3 matrix measurement is based on using an OPC. The matrix defines a connection which traffic will be measured. This measurement shows an amount of specific signalling traffic between two signalling points. Operating Instructions. Reports (Part 3). The MTP3 matrix measurement can be configured by using OI MML command group commands. Service Indicator (SI) defines a concerned signalling traffic and OPC and DPC parameters tell which ones of the signalling points belong to a measurement.Signalling transport over IP (M3UA and IUA) Number of SCTP octets sent Number of retransmitted SCTP packets Number of duplicated TSN received For more information on the M3UA and the SCTP layer counters. If the M3UA-specific statistics are not available.. the M3UA traffic can be monitored by using the MTP3 level matrix measurements. and SI matrix. DPC. Signalling Transport over IP (M3UA and IUA) 22 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . To enable the communication. ASP. SGP-ASP communication The signalling gateway process . AS SG ASP SGP ASP SGP ASP Figure 9. In the SGP-ASP communication the related concepts are AS. An example of SGP-ASP communication DN01141526 Issue 7-0 en # Nokia Siemens Networks 23 (81) . SG. and SGP.application server process (SGP-ASP) communication is needed when communicating between the MTP-3 peers in SS7 and IP domains.Use of M3UA stack 2 2.1 Use of M3UA stack This section describes the use of M3UA stack. a seamless interworking function is needed in the SG at the M3UA layer for the MTP3User peers in the SS7 and IP domains. for example. in the Nokia routing function the SGP (the signalling unit) and the ASP (association) from that SGP are selected at once based on the routing key. AS = MSS. In communication between Nokia network elements. In a strict IETF sense. 24 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . The way the selection is done depends on the traffic handling mode used. is valid for the whole network element collecting all ASPs connected to each SGP (signalling unit). Dynamic routing key registration procedure is used by default. The SGPs inside an SG all have the same availability view of the SS7 network. Each ASP can belong to more than one AS. and the signalling message is forwarded to the signalling unit where the association exists. Inside the association set an association is selected. that is. there is only one active ASP on the list at the time. the SG is first selected based on information in the message. for example. each AS serving its own routing key. an active ASP is selected from the list of active ASPs: if the traffic handling mode is over-ride. When the SGP routes the message. Each ASP inside an AS can be connected to several SGPs. and an SGP is selected inside that SG. See also Association set.Signalling Transport over IP (M3UA and IUA) A group of ASPs connected to an signalling gateway process (SGP) and serving a specific routing key is called an application server (AS). it selects an AS by comparing the information in the message with a provisioned Routing Key (DPC+NI). Using of routing key registration is not mandated if other peer does not support this optional feature. however. After that an active ASP inside that AS is selected. it needs to use the routing context value to indicate to the SGP which routing key traffic the ASP wants to be actively handled. it is recommended that there is only one association in one signalling unit inside one association set. When the traffic handling mode is load-share. the signalling units in those network elements are mapped to ASPs inside the MSS and SGPs inside the MGW. DPC+NI and the SLS value. When a signalling message arrives to the signalling gateway from an SS7 link. SG = MGW. When there is a Nokia network element at the peer. There are two possibilities in routing context value determination: either static configured or determined dynamic by routing key registration. A group of SGPs form an SG. When routing the message at ASP. the AS and SG concepts are mapped to network elements. The association set concept. When the ASP (in this case) wants to indicate to an SGP that it is active for handling specific routing key traffic. With IETF concepts. Furthermore. the M3UA routing function determines first the association set based on comparing the information in the message with a provisioned Routing Key (DPC+NI). based on the SLS value. the AS concept applies in each SGP separately. DPC+NA. 1. if the registration parameter is used inside the association set. That is why it is not necessary to configure a routing context. Signalling messages from the server are destined to the SCCP in the PSTN network element. An example of a Signalling Gateway between two network elements in different protocols DN01141526 Issue 7-0 en # Nokia Siemens Networks 25 (81) . That value is saved to a work file for possible further use in ASPTM messages.1 Example of M3UA usage Signalling messages from the PSTN are addressed to the server network element. where a protocol change from SS7 to SIGTRAN is done. A signalling route goes via the signalling gateway.Use of M3UA stack In Nokia implementation each association can carry only the signalling traffic related to one routing key. the routing context gets its value during routing key registration. However. The static configuration of the routing context is necessary and it might be needed in some compatibility cases. where a protocol change from SIGTRAN to SS7 is done. PSTN Signalling Gateway server MAP TC SCCP MTP MTP IP M3UA SCTP MAP TC SCCP M3UA SCTP IP Figure 10. 2. A signalling route goes via the signalling gateway. There may have STP points in the SS7 path between the SG and the destination PSTN network element. the applications erver process state maintenance message (ASPSM) and application server process traffic manintenance message (ASPTM) messages are not exchanged at all. the following connection is IPSP-IPSP. The IPSP-IPSP connection can be used point-to-point between the M3UA users. This is similar to the previous example. 2. and the IPSP activation are the same. If the dual ended mode of the IPSP-IPSP configuration is wanted. In single ended mode. Signalling messages from the server are destined to the signalling gateway with SPC addressing. A signalling route goes via the signalling gateway. when the Signalling Gateway is able to do the GT translation or when there is an SCCP relay in the IP network. where the protocol changes from SS7 to SIGTRAN. only the 'ASP MESSAGES' parameter should have the value 'Y' at both endpoints. 26 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . the 'ASP MESSAGES IN IPSP' and the 'ASP MESSAGES' parameters should have the value 'Y' at both endpoints of the signalling link. The configuration. association. signalling messages from the PSTN are destined to the server with SPC addressing. If both parameters have the value 'N'. where the message does not go to the SCCP level in the signalling gateway. The IPSP-IPSP is two kind of functional mode. A signalling route goes via the signalling gateway.Signalling Transport over IP (M3UA and IUA) When the SG-ASP communication is used. This is similar to the previous example.2 IPSP-IPSP communication The IPSP-IPSP (IP server process) communication and the ASP-SGP communication are not different except for the fact that the signalling gateway functionality is not needed at either endpoint. For example. where the protocol changes from SIGTRAN to SS7. where the message does not go to the SCCP level in the signalling gateway. In this case. The GTT in the signalling connection control part (SCCP) of the signalling gateway gives as a result the SCCP peer located in the IP network.1 Use of IPSP-IPSP example at the M3UA PSTN Signalling Gateway server MAP SCCP TC SCCP MTP MTP IP M3UA SCTP MAP TC SCCP M3UA SCTP IP IPSP-IPSP or SG-ASP Figure 11. When the IPSP-IPSP communication is used.Use of M3UA stack 2. DN01141526 Issue 7-0 en # Nokia Siemens Networks 27 (81) . both the IPSP-IPSP and the SGP-ASP communication is possible. The global title translation (GTT) in the SCCP of the signalling gateway gives as a result the SCCP peer locating in the SS7 network. An example of combined Signalling Gateway and IPSP-IPSP In the example above. The signalling messages from the server are destined to the signalling gateway with global title (GT) addressing. the connection between the signalling gateway and the server is an IPSP-IPSP connection.2. signalling messages from the public switched telephone network (PSTN) are destined to the signalling gateway with GT addressing. the operator can configure the value of the routing context manually. but if you want to have a static configuration for some reason (for example. The routing context parameter is a 4-byte value (integer) which is associated to that routing key in a 1-to-1 relationship. Therefore. the routing context parameter uniquely identifies the range of signalling traffic associated with each Application Server that the ASP is configured to receive. SI (Service Indicator). Routing context values are either configured using a configuration management interface. NA (Network Appearance). At an ASP. OPC list (Originating Point Code). refer to SCTP Configuration Handling . The parameter DPC is obligatory because it is the SPC address used by the AS. Either one or several of these parameters as an identifier for an AS can be used as a routing key. the routing context can be viewed as an index into a sending node's Message Distribution Table. Routing context is a value that uniquely identifies a routing key. containing the routing key entries. An application server process may be configured to process signalling traffic related to more than one Application Server. SSN. In case of static configuration. The network appearance parameter is included in the association set parameters. Dynamic Routing Key registration is used by default.Signalling Transport over IP (M3UA and IUA) 2. This especially applies to the SGP when there is a Nokia network element at the peer. Routing key is a part of the message header. The other parameters: SI. or CIC are not included in the routing key because it is expected that the network element operating as an AS can handle the message distributing function itself. In ASP Active and ASP Inactive management messages. The DPC and network appearance together form the only routing key that is supported.3 Routing key and routing context The distribution of the SS7 messages between the SGP and the Application Servers is determined by the routing keys and their associated routing contexts. The Internet Engineering Task Force (IETF) standard for M3UA determines a group of SS7 parameters that can be used as an identifier for an AS. over a single SCTP Association. 28 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . or by using specific procedures of routing key management. Both are also mandatory parameters in the routing key. The network appearance maps to a network indicator. insure compatibility against other vendors' product). These parameters can be DPC (Destination Point Code). or certain value domains of the number space of CIC (Circuit Identification Code). the signalling traffic to be started or stopped is selected by the routing context parameter. The migration can be done without configuration changes to PSTN or public land mobile network (PLMN) network elements by the management cluster. When the MTP of the Signalling Gateway receives a User Part message destined to the management cluster. A signalling management cluster is applicable when a signalling point becomes an Application Node as it is connected to a Signalling Gateway. because some radio network controller implementation supports only associated signalling mode. that is. Nokia recommends that with the MSC Server concept the quasiassociated signalling mode is used. and therefore stripped of its MTP level 2 connections to other network elements. that of the Application Node. MTP level 2 connections and other MTP functionalities of an SPMC are in the Signalling Gateway. The SPMC is an entity which consists of the SG and Application Node. as they see nothing from the management cluster but the same old signalling point code. Then other network elements need no configuration changes. it forwards the message to the Application Node. it is not mandatory to use the management cluster in MSC Server migration.Use of M3UA stack 2. MGW is used as an STP. but is visible to other network elements only with one signalling point identity. However. which makes it possible to design a signalling network more redundant. One practical example of transition from signalling points to signalling management clusters is the migration from Mobile Switching Centers to MSC Servers and Multimedia Gateways.4 Signalling Point Management Cluster Signalling Point Management Cluster (SPMC) is an example of a configuration where two network elements share a Signalling Point Code (SPC). DN01141526 Issue 7-0 en # Nokia Siemens Networks 29 (81) .or A-interface. while the User Part functionality of the cluster is in the Application Node. A management cluster may also be needed with the MSC Server concept in IU. 30 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en .5 Message structure of M3UA The basic overhead on SIGTRAN contains the following message headers: IP.NI=8 TMSC TDM SG M3UA ASP Figure 12. and M3UA. An example of Signalling Point Management Cluster Note Signalling Point Management Cluster shall be used only between one MSC Server and one MGW. 2.Signalling Transport over IP (M3UA and IUA) DPC=123. Signalling Point Management Cluster does not work according to the specifications if more than one MGW is configured. SCTP. The OPC and DPC fields are both 4 bytes long and the rest of the routing label parameters like SI. Chunk description. The size of the Common Message header of the M3UA is 8 bytes. The main part of the bit rate is generated from the payload data messages. The length of the IPv4 header can vary between 20 and 60 bytes. The SCTP header should contain a Common header. The size of the IP header depends on what version of the IP stack is used.Use of M3UA stack . Therefore. . The Routing label of the MTP3 message is encoded in separate fields. IPv4 or IPv6. and SLS are encoded in one dword (4 bytes). The total length of the M3UA message header is 24 bytes in the Payload Data message. NI. Message Priority. Its size is 8 bytes. Options are not commonly used on the IPv4. The length of the Common header is 12 bytes. and Payload identifier. an example describes only the structure of the payload data. The remaining 40 bytes is the length of the option field. The length of the IPv6 header is 40 bytes + options fields. The total SCTP header size is 28 bytes. The optional Network Appearance parameter is used in M3UA. The length of Chunk Description is 4 bytes. The length of Payload identifier is 12 bytes. . The Common message header exists in every M3UA message. 20 bytes is the length of the basic IP address in IPv4. DN01141526 Issue 7-0 en # Nokia Siemens Networks 31 (81) . Usually some of those option fields are included in the message when it is using IPv6. Header length Type of service Flags Protocol Source IP address Destination IP address Options (variable length. usually this field is not used) Source Port Number Verification Tag Checksum Chunk Type Chunk Flags TSN Stream Identifier Stream Sequence Number Chunk Length Destination Port Number Total length Fragment Offset Checksum 31 Identification Time to live Payload Protocol Identifier Version Reserved Message Class Message Type Message length Tag=210 Originating Point Code Destination Point Code SI NI MP SLS Length protocol data of the M3UA users (Variable Length) Figure 13. Message structure of M3UA 32 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en .Signalling Transport over IP (M3UA and IUA) 0 Ver. IUA protocol DN01141526 Issue 7-0 en # Nokia Siemens Networks 33 (81) .931 IUA Q. In this solution.931 MGW (SG) IUA MSS Q.Use of IUA 3 Use of IUA IUA provides a solution for Standalone MSC Server to control PBX connections over the IP network. The IUA protocol is needed in case an MSC Server has only IP interfaces available.921 Q. The Control Plane of the PBX connection is transported between MGW and MSS over the IP network by using the IUA protocol. D-channels are terminated into the Signalling Gateway (for example MGW). PBX Q.921 SCTP SCTP IP IP ISDN IP Figure 14. IUA uses the ASP-SG mode where MGW works as a Signalling Gateway and MSS works as an AS. The solution comes from the IETF working group (SIGTRAN). The application which controls the PBX connection is located in the MSS. Here. This mode is similar to the M3UA ASP-SG mode. Q921 protocol is terminated in the SG. and IUA. Usually some option fields are included in the message when it is using IPv6. The size of the Common header is 8 bytes. A tag after an IUA message header indicates what message is in question. 20 bytes is the length of the basic IP address in IPv4. The length of the IPv4 header can vary between 20 and 60 bytes. a Chunk description. The remaining 40 bytes is the length of the option field. Nokia product supports only the integer based IUA header. RFC 3057 defines integer based or text based IUA message headers. Options are not commonly used on the IPv4. 34 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . The length of the Payload identifier is 16 bytes. The IUA message starts a Common message header. The message below describes a protocol data message structure. IPv4 or IPv6. The length of the Chunk Description is 4 bytes. . The total length of the IUA message header is 28 bytes. and its fixed length is 16 bytes. The total SCTP header size is 28 bytes. .Signalling Transport over IP (M3UA and IUA) 3. SCTP.1 Message structure of IUA The basic overhead on SIGTRAN contains the following message headers: IP. The length of the Common header is 12 bytes. The length of the IPv6 header is 40 bytes + options fields. and a Payload identifier. Immediately after the Common header is the IUA message header. . The SCTP header should contain a Common header. The size of the IP header depends on what version of the IP stack is used. Header length Type of service Flags Protocol Source IP address Destination IP address Total length 31 Time to Live Checksum Options (variable length. usually this field is not used) Source Port Number Verification Tag Checksum Chunk Type Chunk Flags TSN Stream Identifier Stream Sequence Number Payload Protocol Identifier Version Reserved Message Class Message Type IUA common headers and protocol data 35 (81) Destination Port Number SCTP Common header and payload data Chunk Length Message Length Tag = 0x1 Interface Identifier (Integer) Tag = 0x5 DLCI Tag = 0xE Length = 8 Spare Length Length protocol data of the IUA users (Variable Length) Figure 15.Use of IUA 0 Ver. Message structure of IUA DN01141526 Issue 7-0 en # Nokia Siemens Networks IP version 4 header Identification Fragment Offset . Signalling Transport over IP (M3UA and IUA) 36 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . the SEP network element is usually in the IP network. When the IP connection is used. but also any other network element where signalling is transported via the IP network. a network element working in both network types. the signalling unit must have an ETHERNET port. the other can be used as a backup. through which it can be connected to the network element internal LAN. it is connected to the time-division multiplexing (TDM) network via an SG. If one of them is unavailable. The separator (SEP) network element acts as an AS. Basic example of a network that uses IP In the example figure. STP SG SEP IP SEP STP SG Figure 16. that is. The AS can be a server or a database. DN01141526 Issue 7-0 en # Nokia Siemens Networks 37 (81) .Basic structures of M3UA network 4 Basic structures of M3UA network When the IP transport is used in the signalling network. there are two SGs. The M3UA specification does not describe the M3UA level STP functionality. MSS TMSC MGW SRRi HLR MSC IP SMSC TMSC MGW SRRi SCP IPSP . some of them will probably be used also as an SG when implementing SIGTRAN. the implementation and O&M work required for maintaining a full-mesh network in large networks would require too much effort. it would be optimal to create a fullmesh network of logical connections between SIGTRAN elements. If the GT is used for routing. In the networks which already have STPs. as M3UA uses associations between SEPs. Use of STPs To save bandwidth in the IP network. M3UA signalling is implemented as point-to-point signalling. however. there can also be an SCCP level STP inside the IP network. the STP functionality is implemented in the DX200and IPA2800-based network elements according to the ITU-T Q704 recommendations. An SG can work as an STP as in the MTP3 network if SGs are connected to each other via TDM or ATM-based connections. The message is then passed on to the next signalling point through an IPSP-IPSP type M3UA connection. An example of an M3UA network with SCCP relay function SS7 message routing can also be based on an SCCP GT address.IPSP Figure 17. which is an AS from the SG's point of view. At least where SRRi is 38 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . However. The SG routes messages to the STP point.Signalling Transport over IP (M3UA and IUA) In the IP network. the SCCP finds out the next signalling point where the message has to be sent. Here the use of SIGTRAN STPs becomes possible. In that node. There should always be at least two STPs in physically separate sites to allow redundancy.Basic structures of M3UA network used for free numbering or mobile number portability. DN01141526 Issue 7-0 en # Nokia Siemens Networks 39 (81) . This has an effect when calculating the bit rate offered to the IP backbone as each message has to travel several times via the backbone (unless it is intra-site). the SRRi can work as an SCCP level STP (or SCCP relay) inside the IP network. In that case. the signalling has to go via the SRRi. Signalling Transport over IP (M3UA and IUA) 40 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . Packet loss may happen in the M3UA as on MTP level 3. You can either plan a redundant LAN and the redundancy of associations or plan the LAN using SCTP multi-homing. The M3UA does not contain for example signalling link switchover within signalling link set. and therefore it cannot achieve the same service level as MTP3 in message transport. See Q706 ITU-T recommendation for reference. DSCP can be set using known (M3UA server) port 2905. An application of the M3UA sets real limits. Redundancy of associations can be handled on several levels: DN01141526 Issue 7-0 en # Nokia Siemens Networks 41 (81) . In case of IUA. The settings of the DiffServ code used for M3UA signalling are common to all those applications whose traffic goes via the same SCTP association. The DiffServ code can also be set to each SCTP association individually. such as the point-to-point capacity of the LAN. In case of M3UA. and also using that specific port number with the DiffServ configuration. It may not be necessary to do the steps in the order they are presented here. It is recommended that the same DiffServ is used for all SCTP associations in the association set in the M3UA. should be known when planning the site configuration. but this requires configuring a specific port number to client associations. Choose one of the alternatives described in the first step below. The maximum delay that is allowed between the network elements is not specified. The LAN infrastructure. TCP/IP stacks support setting DSCP.Planning site configuration for signalling 5 Planning site configuration for signalling This procedure lists the things you need to consider when planning the site configuration for signalling over IP solutions. DSCP can be set using its well known port 9900. The SIGTRAN is not supported with a network element of the sub track mechanics. Tunable SCTP parameters are necessary for the associations to function according to the Q706 ITU-T recommendation. on the unit level . Static IP routes should be logical. IP addresses should be logical. Good IP addressing and good IP network design is a key issue to avoid such a situation.Signalling Transport over IP (M3UA and IUA) . it is possible to do a signalling unit switchover procedure so that the current M3UA configuration is recovered. 2. One example of how number of point-to-point IP route can be avoided: 42 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . the number of IP routes increases rapidly in each peer. For this reason. on the network element level: If signalling units are configured with logical IP addresses (which is highly recommended). Note SCTP multi-homing configuration is required to configure two IP subnetworks to each signalling unit. This enables making a unit switchover so that IP addresses remain the same. This helps to make a static IP-route configuration and ensure that after the unit switchover signalling connection works as before the unit switchover. Before you start 1. 0/16) MSS C2: net 133.30.40.40.0/24 net 132.6.6. This kind of configuration ensures that the primary path is separated from the secondary path.0.Planning site configuration for signalling Site A MSS A1: net 133. EL0 and EL1 should belong to different sub-networks.9.3 platform) net 133.0/16) Site B MSS B1: net 133.4.0. Point-to-point message travelling time should be explored.0/24 MGW B2 (A4.30.0/24 Figure 18.11.0/24 net 132.40.4.2.40.30.30.40.0/24 net 132.40.0/24 net 132.0/24 IP Backbone 1 (133. DN01141526 Issue 7-0 en # Nokia Siemens Networks 43 (81) . 4.3 platform) net 133.0/24 net 132. Avoiding number of point-to-point IP route 3.0/24 IP Backbone 2 (132.0/24 Site C MGW C1: (A4.30.2. In this case.30.11.9. Signalling over IP connection should be designed by using multihomed connections if possible. it is important to reduce it to the same level as that of the SS7 network by tuning the SCTP parameters. see section SCTP multi-homing.Signalling Transport over IP (M3UA and IUA) If the failure detection time has been planned. 44 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . a) Plan the configuration using SCTP multi-homing. OR b) Plan the configuration using redundant LAN and the redundancy of associations. It is recommended to use a symmetric configuration in the case of SCTP multi-homing. In the redundant LAN configuration both Ethernet ports of signaling unit have the same logical IP address but only one of them is in active state. Note Please note the difference between the concepts of redundant LAN and SCTP multi-homing. Steps If the system is taken into use for the first time. EL0 and EL1 should belong to different sub-networks. so that both Ethernet Interfaces are active simultaneously. Creation of logical IP address in the signalling unit changes the unit automatically from SP-EX state to WO-EX state. In the SCTP multihoming configuration both Ethernet ports of signaling unit have own logical IP address from different IP subnetworks. SCTP multihoming enables better redundancy and therefore it is the recommended redundancy mode for signalling. For more information on SCTP configurations. 1. you should create the IP configuration before creating the SCTP association. The redundant LAN means that the system contains a standby Ethernet Interface. 4.0::EL1. This gives redundancy only against Ethernet port failure or another HW failure in the network element.Planning site configuration for signalling This mode should only be used when SCTP multi-homing cannot be used. With this command. Logical IP addresses should be used. First configure a network interface(s) to unit(s). another Ethernet port (EL1) can take the responsibility for the failed one. Associations are redundant in one signalling unit. a failure detection time of association could be reduced to the same level as that of the SS7 network or LAPD required. Configure the lower level LAN. EL0) fails. so that if the primary Ethernet port (for example. This concept does not guarantee that none of the signalling messages are lost during a short LAN failure. Tune the SCTP parameters.1::EL0. DN01141526 Issue 7-0 en # Nokia Siemens Networks 45 (81) . For more information on SCTP parameters. the operator can define protocol by protocol classification to each of them individually. Use logical static IP route configuration. For more information. Example 1. Configure port-based classification and marking (Q8N). refer to section Modifying association parameters. 3. refer to Site Connectivity Guidelines. 5. ZQRA:SIGU. Create static IP routes (QKC).0::EL0. ZQRA:SIGU. 6. For more information. EL0 and EL1 should get the same logical IP address. Configure the LAN. By tuning the SCTP parameters. ZQRA:SIGU. 2. Plan IP addresses management and configuration. refer to the Control LAN descriptions in the network element engineering descriptions. 41.45.228. Assign an IP address to the each available Ethernet interface.24.41. And ZQKC:SIGU.L. ZQKC:SIGU.228.45.228.2::EL1.46.0". And ZQRN:SIGU.40.1": LOG:. ZQRN:SIGU.46.228.EL0.1::EL1:"131.228.45.10".24:"131. ZQRN:SIGU.228.1::EL0:"131. ZQRA:SIGU.0::VLAN27. ZQKC:SIGU.11".0::"132.1": LOG:.46. And ZQRN:SIGU.24:"131.24. Example ZQRA:SIGU.Signalling Transport over IP (M3UA and IUA) ZQRA:SIGU. ZQKC:SIGU.1::EL1.228.24:"131.10".L.228.24:"131.0::EL0:"131.L. ZQKC:SIGU.40.40.27.0".41.0::EL1:"131.0".11".24.24.2::EL0.24.2::EL1:"131.228.L. ZQRA:SIGU.2::"132.228.1": LOG:. 3. 4.41.1": LOG:. Configure static routes. 46 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . 2.0".0".228.0::"132.228.24:"131.L.1::"132.2::EL0:"131.0".12".1": LOG:. ZQRN:SIGU.228.41.41.1": LOG:.2::"132.40.228.228.228.12".228.24:"131.40.L.1::"132. And ZQKC:SIGU.40.24.228. ZQRN:SIGU. Configure VLAN interfaces (if desired). 228.24. If tunnelled connection is used.228.24:"131. ZQRA:SIGU. Use ZQRA command for modification. Example Using the redundant LAN concept to do the SCTP configuration.12".1": LOG:.1::EL0.45.40. one redundant pair is configured with one MML-command. 2.10". ZQ8N:132::9900:0. And ZQKC:SIGU.228.0". Assign the same logical IP address to each available Ethernet interface.11".228.EL1:"131. ZQKC:SIGU.24.2::"132.EL1:"131. 3.40. And ZQRN:SIGU.228.Planning site configuration for signalling 5. Configure the DiffServ code value as '0' for the default SCTP port 2905 (M3UA) and 9900 (IUA).g.228. 6. 4.24:"131.2::EL0.228. Configure the DiffServ code value as '0' for the default SCTP port 2905 (M3UA) and 9900 (IUA) ZQ8N:132::2905:0.40.0". Modify MTU size if necessary.228. Configure the VLAN interfaces (if desired).1": LOG:.L.45.40.0::"132.1": LOG:.0::EL0:1400.0".L. DN01141526 Issue 7-0 en # Nokia Siemens Networks 47 (81) .228.EL1:"131. And ZQKC:SIGU. And ZQRN:SIGU. ZQ8N:132::2905:0.40.0::EL0.24:"131.45.L. MTU size might be needed to reduce. ZQRN:SIGU.40.24. e. 1.1::"132. Configure static routes. Signalling Transport over IP (M3UA and IUA) ZQ8N:132::9900:0. 48 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . then the MTU size might need to be reduced. 5. Modify the MTU size if necessary. If a tunneled connection is used. 4. each association can take care of the others' traffic if some of them fail. For more information. Plan the redundancy of connections. and that the number of associations in an association set should be 2. For more information. Plan what kind of a connection is used. or 16. Spread M3UA associations to as many signalling units as possible considering the number of units in both ends of the association set. refer to section MTP level signalling network in Common Channel Signalling (MTP. 8. refer to section Modifying association set level parameters of M3UA and Modifying SCTP association parameters Steps 1. SCCP and TC). DN01141526 Issue 7-0 en # Nokia Siemens Networks 49 (81) . refer to Use of M3UA stack.Planning M3UA network 6 Planning M3UA network Note Remember to check if the association set and SCTP association parameters you plan to use are compatible with the other end. Plan if Signalling Point Management Cluster is used or not. 2. otherwise. For more information. If an association set contains more than one SCTP association. The recommended number of SGs is two. Remember that 4-bit Signalling Link Selection (SLS) is used for load sharing between associations. the load in each association is not even and the unit load will not be even either. 3. You should determine whether you are using an ASP-SGP or an IPSP-IPSP connection. through which it is not possible to direct traffic destined to another DPC (STP traffic). and TC). 5. The basic rule is that with signalling route set between MSS and MWG the IETF signalling route parameter set is used in case of M3UA connection.This recommendation should be followed also with signalling route sets which are leading to the BSC or RNC via MGW. All signalling route sets which are available via MGW shall be configured so that a used signalling route parameter set is based on some of the MTP3 standards. SPMC configuration can also be used when different M3UA configurations need to be used together. 4.Signalling Transport over IP (M3UA and IUA) SPMC can be used if for some reason it is not possible to give separate SPC addresses to the SG and the network element functioning as an ASP. Plan the SCCP level signalling network. Plan the signalling route set parameters carefully. Proceed with planning according to section SCCP level signalling network in Common Channel Signalling (MTP. That kind of parameter sets are for example ITU-T and ANSI parameter sets. but it is capable of receiving and handling the signalling traffic destined to the SPMC. Note Signalling route parameter set for A-interface (parameter set 1 listed by NNI MML command) shall be used only when signalling route set leads directly to an adjacent signalling point. 50 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . SPMC is a special configuration. SCCP. the number of stream in the M3UA association is 16. Steps 1. Create an association set (OYC). Otherwise. Remember to check if the association set parameters are correct. Add associations to the association set (OYA). It should be noted that if other peer cannot support as many inbound streams as the client has assigned an outbound stream. For more information. Note By default. This should be taken into account when considering the resources of the client. Configure transport addresses of SCTP association (OYP). DN01141526 Issue 7-0 en # Nokia Siemens Networks 51 (81) . refer to section Planning site configuration for signalling. 3. 2. refer to section Modifying association set level parameters of M3UA. then SCTP protocol establishes an association by using lower value of number of stream. For more information. there may be problems after unit switchover. Note You should always use the logical IP address of the unit and logical static route configuration when possible.Creating M3UA configuration 7 Creating M3UA configuration Before you start Create first the LAN configuration. 6. To interrogate the states of the associations. the system automatically attempts to activate all the associations belonging to the association set.41. The SIGU units of the MSS (MSS10) are as follows: SIGU 0 EL0 131.10 52 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . The configuration example can be applied to all environments where the M3UA is planned to be used. A network indicator value and signalling point code address of destination point are defined explicitly where the association set is connected. Create IP type SS7 signalling link and link set (NSP). 5. Check the associations (OYI). Create the SS7 signalling route set (NRC). SCCP.228. Activate the signalling network configuration.40. refer to section Activating MTP configuration in Common Channel Signalling (MTP. In this step. For more information. The SS7 signalling link is active if at least one association belonging to its association set is active. Verify that the associations were created correctly and that they have correct IP addresses by using the OYI command.228. the operator creates a signalling link set to destination point. The activation procedure is the same as when you create a non-IP connection. When you activate an SS7 signalling link. Activate the SCTP associations of the association set (OYS). Further information: Example: Creating IP configuration between MSS (client) and MGW (server). use the OYI command. 8. 7.10 EL1 131. 4.Signalling Transport over IP (M3UA and IUA) In this phase the operator defines the source and destination port numbers and source and destination IP addresses for the SCTP association. and TC). Note This is only one example of the M3UA usage. 11 SIGU 2 EL0 131.40.:SS7:.2.228.40.:SS7:. ZOYA:MGW400:SIGU. ZOYA:MGW400:SIGU.1.4 EL1 132.228. Add three associations to the association set MGW400.12 The ISU units of the MGW (MGW400) are as follows: ISU 0 EL0 132.45. 2.6 Creating M3UA configuration in the MSS Use these MML commands when creating M3UA configuration in the MSS.11 EL1 131.228.46.228.6 EL1 132.12 EL1 131. Add SCTP transport addresses to the association.46.228.228. 3.228.41. DN01141526 Issue 7-0 en # Nokia Siemens Networks 53 (81) . ZOYC:MGW400:C.0.45.228. Create an association set called MGW400.4 ISU 1 EL0 132. 1.45.228.Creating M3UA configuration SIGU 1 EL0 131.46. ZOYA:MGW400:SIGU.:SS7:.5 EL1 132.5 ISU 2 EL0 132.228.41. Activate the SCTP associations.24. 5.46.0:"131.>signalling point code>:.5".228. ZNLA:<signalling link number>.2:"131.24.:.228.41. 54 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en .41.10":"131. ZOYP:M3UA: MGW400.: MGW400. ZNVA:NA0. ZOYQ:SIGU.228."132.45."131.228.4".4"."131.40.228. Create the SS7 signalling route set with the NRC command.45.40.228.46.6"."132."132.24.24.1:"131.228. ZNLC:<signalling link number>. 9. ZNVC:NA0.2:ACT. Create an SS7 signalling link set to use the association set MGW400. Activate Signalling route sets.45. 7.24. ZOYS:M3UA:MGW400.<signalling link number>. <signalling route set name>..<signalling link set point code>. ZNRC:NA0:<signalling point code>.:ACT.Signalling Transport over IP (M3UA and IUA) ZOYP:M3UA: MGW400.12":"131.46.<signalling point code>:.10"..228. Activate the signalling links. ZOYI:NAME=MGW400:A. 6.228. ZOYP:M3UA: MGW400.11":"131..12". Verify the IP addresses in the association set MGW400.1:ACT. ACT. 8.24.5".. 4. Interrogate Average M3UA CPU Load caused by M3UA connection in the SIGU units during last 5 minutes period."131.228. ZOYS:M3UA:MGW400.41.228.228.6".0:ACT.40. <signalling link set name>. 10. ZOYS:M3UA:MGW400. ZNSP:NA0.11". Creating M3UA configuration The Average M3UA CPU Load can be interrogated if licence has been purchased. DN01141526 Issue 7-0 en # Nokia Siemens Networks 55 (81) . Signalling Transport over IP (M3UA and IUA) 56 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . 2. Plan D-channel configuration. Plan the redundancy of connections. IUA connection always uses ASP-SGP configuration. refer to Use of IUA. Spread IUA associations to as many signalling units as possible considering the number of units in both ends. DN01141526 Issue 7-0 en # Nokia Siemens Networks 57 (81) .Planning IUA network 8 Planning IUA network Note Remember to check if the SCTP association parameters you plan to use are compatible with the other end. Steps 1. For more information. For more information. The maximum number of D-Channel within SCTP association depends on the number of streams. refer to section Modifying SCTP association parameters. Signalling Transport over IP (M3UA and IUA) 58 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . Verify that the associations were created correctly and that they have correct IP addresses by using the OYV command.21. Otherwise.Creating IUA configuration 9 Creating IUA configuration Before you start Create first the LAN configuration. Check the associations (OYV). 5. Configure SCTP association transport addresses (OYP) ZOYP:IUA: MGW400:"131. 3. For more information.32.43. refer to section Modifying SCTP association parameters. Create D-channels (DWC). Remember to check if the SCTP association parameters are correct.43. 4. refer to section Planning site configuration for signalling. Activate the association (OYS). Note You should always use the logical IP address of the unit and logical static route configuration when possible."132.23..234". Create an association (OYX).234". For more information.23. Activate the D-channel configuration (DWE).24. 6. 2.432".24.32.21.432":"131."132. DN01141526 Issue 7-0 en # Nokia Siemens Networks 59 (81) . Steps 1. there may be problems after unit switchover. 40.10 SIGU 1 EL0 131.46.12 The ISU units of the MGW (MGW400) are as follows: ISU 0 EL0 132.40. use the OYV command.228.11 EL1 131.40.45.228. Further information: Example: Creating IP configuration for PBX between MSS (client) and MGW (server).10 EL1 131.228.228. the system automatically attempts to activate the association.228. The SIGU units of the MSS (MSS10) are as follows: SIGU 0 EL0 131.11 SIGU 2 EL0 131. Note Note that this is only one example of the IUA usage.228.4 EL1 132.41.12 EL1 131.228.41.4 ISU 1 60 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en .Signalling Transport over IP (M3UA and IUA) The activation procedure is the same as when you create a non-IP connection.41. When you activate a D-channel.228. To interrogate the states of the associations. Create the D-channels with the DWC command. ZOYP:IUA: MGW400:"131.4".228.24.0:IETF:.228. Add SCTP transport addresses to the association. ZOYV:NAME=MGW400:A.46.228.228. 5.5 EL1 132.228.228. Activate the D-channel.41.45.46.10":"131.24. 3. Create an association called MGW400.5 ISU 2 EL0 132.2:SIGU. ZDWE:PBX2:WO. ZOYX:MGW400:IUA:C:SIGU.40. 4.0:MGW400.228.10". DWC:PBX2. DN01141526 Issue 7-0 en # Nokia Siemens Networks 61 (81) .4"..45.Creating IUA configuration EL0 132. 6.45. 1."132.46. ZOYS:IUA:MGW400:ACT.228.6 EL1 132. 2. Verify the IP addresses in the association MGW400."131. Activate the association.6 Creating an IUA configuration in the MSS Use these MML commands when creating an IUA configuration in the MMS. Signalling Transport over IP (M3UA and IUA) 62 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . M3UA SPECIFICATION VERSION 05 (DRAFT) 7 . If other peers support a different version of the M3UA. If the role of the association set is “Client”.. Modifying association set level parameters of M3UA Association set level parameters NAME ROLE ASSOCIATION SET NAME Symbolic name of the association set.. ASSOCIATION SET ROLE The role of the association set (SERVER/CLIENT).. This parameter also controls function of M3UA management. M3UA SPECIFICATION VERSION 07 (DRAFT) 9 . then the version parameter should be changed to the same version as that of the remote peer. the exchange starts to ASP state management procedures and other peer only send an acknowledgement message in both ASP and IPSP cases. M3UA SPECIFICATION VERSION 09 (DRAFT) VERSION DN01141526 Issue 7-0 en # Nokia Siemens Networks 63 (81) .Modifying Sigtran parameters 10 10.. Supported versions are as follows: 5 .. then the own peer initializes all SCTP associations of that association set.0 (RFC). M3UA SPECIFICATION VERSION Used version of the M3UA specification.1 Modifying Sigtran parameters This section describes how to modify Sigtran parameters.. If the role is “client”. The default is M3UA version 1. By default.0 (RFC) Note By default. If remote peer's implementation does not support centralized ASP management in the AS. ASP REG SSNM NETWORK NETWORK APPEARANCE Network appearance which is used in the association set in question. M3UA SPECIFICATION VERSION 1. This is an optional parameter. REGISTRATION REQUEST The parameter controls if dynamic routing key registration is in use or not. dynamic routing key registration is used. this procedure may be denied. if dynamic routing key registration is not an option in the receiving party's M3UA.Signalling Transport over IP (M3UA and IUA) 16 . By default. However. That feature can be used only with Loadsharing mode.. Normally. ASP MESSAGES The parameter controls if ASP management messages (ASPTM and ASPSM) are used or not in the association set.0 of the M3UA is used. Version 1. and therefore not necessarily supported in all M3UA implementations. This parameter controls how traffic is routed between SCTP associations into the association set. If not supported.. there is no need to modify this parameter except in very special cases. Two types of traffic modes are supported: over-ride and load sharing (default).0 is used. The broadcast of the SSNM messages to all active ASPs are not used normally. ASP management messages are in use when the version 1. the SSNM messages may be needed to broadcast to each active ASPs. Network 64 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . TRAFFIC TRAFFIC MODE Traffic mode of the association set. SSNM MESSAGES NEED TO BE BROADCASTED TO ALL ASPS The parameter controls the broadcast of the SSNM messages. 0 . the first data stream number is 1.Modifying Sigtran parameters Appearance can be removed from SSNM messages with the NNM command (Parameter Group D. The first data stream number might only be needed to be modified in case where remote peer supports some earlier M3UA draft specification. ROUTING DN01141526 Issue 7-0 en # Nokia Siemens Networks 65 (81) . From Data message Network Appearance can be removed so that its value is modified as a maximum one. parameter USE_OF_M3UA_NW_APP). The value of the Routing Context can be configured only when the registration request parameter is inactive.4294967294 Range of Network Appearance parameter value 4294967295 Network Appearance is not used in data message IPSP SENDING OF ASP MESSAGES IN IPSP CONNECTION The parameter controls the sending of ASP management messages in the IPSP mode.0 is used.4294967294 Range of Routing Context parameter value 4294967295 Routing Context is not supported FIRST FIRST DATA STREAM NUMBER The parameter is defined as the number of the first data stream. the system works so called double ended IPSP-IPSP mode. Routing Context parameter can get the following values: 0 . ROUTING CONTEXT The parameter is the defined value of the Routing Context. When this parameter is set on. When M3UA version 1. In other words. the first data stream must be 1. Normally. This parameter needs to be modified only in case of static configuration or in case when the remote peer does not support Routing Context parameter. the server also starts the ASPTM and ASPSM management sequences. min repeatedly. If the RTO is computed to a lower value than RTO. The association set parameters can be interrogated with the OYI command. If the delay time of a SACK message from peer which acknowledges a sending data message exceeds the value of RTO. Change the parameter values (OYM). These parameters control how the SCTP association is working. the RTO is rounded up to the value of the RTO. RTO. Check whether the parameters have suitable values (OYI). you may need to change the parameters if the remote peer supports a different version of the M3UA specification or the remote peer does not support all the optional M3UA functionalities. Before you start Steps 1. 10. Note The above parameters can be modified only when the association set is deactivated. All of those parameters are related to the M3UA.min The minimum value of retransmission time-out.min has. However. Find out the reason why and which parameters need to be changed.min. 2.Signalling Transport over IP (M3UA and IUA) Each association set has its own parameters. The association set can be deactivated by deactivating a signalling link which is using that association set. it is not necessary to change the parameters. this value needs to be re-adjusted to LAN 66 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . You can change the parameter values with the OYM command. In many cases. The association set level parameters can be modified by using the OYM command. This parameter is normally used to monitor the time used in retransmitting.2 Modifying SCTP association level parameters The SCTP association level parameters are the following. If the message average Round-Trip Time (RTT) is less than 70 ms.Retrans DN01141526 Issue 7-0 en # Nokia Siemens Networks 67 (81) . min. The default value of the SACK period is 200 ms.Modifying Sigtran parameters capacity. This parameter is used as default RTO value just after an SCTP association is established. The heartbeat interval in real life is the sum of the following parameters: HB. When this threshold value is reached.max The maximum value of the retransmission time-out. path is marked inactive. min parameter is 150 ms in the SS7 parameter set.Max. A maximum delay which message receiver shall wait for another data chunk until it shall send SACK message for an acknowledgement of a received data message. The SACK period can never be more than 500 ms.max parameter is 200 ms in the predefined SS7 parameter set. The signalling common transport protocol (SCTP) increases the re-transmission time supervision exponentially after each re-transmission attempt. and the value of small random jitter. the predefined parameter set (called SS7) can be used. interval value and the value of RTO. Default value of the RTO. This parameter is the basic value of the heartbeat interval. When the computational RTO exceeds the value of the RTO. the SCTP employs the RTO.Interval Path.interval value.min parameter should be at least twice bigger than the RTT value. Default value of RTO. unnecessary message retransmissions are avoided. RTO.min come from the parameter set. This parameter is used only for secondary path until the first heartbeat sequence is gone through. Note The value of RTO.max parameter. RTO. By following this rule. Used HB. RTO. This parameter defines a maximum number of unacknowledged transmissions (including heartbeats) per path. but the value of jitter can be varied between networks and network elements.initial SACK period HB.max to monitor re-transmission. the SCTP stack might send the SCTP control message and data message within one datagram. When this threshold value is reached. By default bundling is used in the system. Note Even if the bundling option is not set on. CRC32c is used by default. and the second one contains a pre-tuned parameter to ensure that the MTP performance requirements of an SS7 network are met.5 s 1s 2s 200 ms 68 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en .max RTO. Also retransmitted messages are allowed to send within one datagram even if bundling parameter is denied that. association is aborted. BUNDLING This parameter controls if the user application allows or does not allow more than one chunk within the SCTP packet. Table 1. IETF RTO. The SCTP parameters should be uniform at both ends of the SCTP association.init HB. The first one contains the IETF compliant parameters. CHECKSUM This parameter controls which Checksum method is used in an association. but the CRC32c checksum is recommended.period 1s 60 s 3s 30 s 200 ms Summary of suggested parameter sets SS7 150 ms 200 ms 200 ms 1s 110 ms GENERAL 250 ms 400 ms 200 ms 1s 200 ms SATELLITE 750 ms 1.min RTO. The Adler-32 or the CRC32c method can be used. The following table summarizes the differences of predefined parameter sets.Signalling Transport over IP (M3UA and IUA) Association. The system includes two pre-packaged SCTP parameter groups.Retrans This parameter defines a maximum number of unacknowledged transmissions (including heartbeats) per association.Max. Each user message occupies its own DATA chunk if bundling is not allowed.interval SACK. DN01141526 Issue 7-0 en # Nokia Siemens Networks 69 (81) . This parameter set takes into account a delay caused by a satellite. This parameter set is not feasible for telecom signaling purpose. That parameter set helps to start signalling transport over IP configuration. Using SS7 parameter sets an exacting requirement for WAN environment.Modifying Sigtran parameters Table 1.) SS7 2 4 CRC32c Yes GENERAL 2 4 CRC32c Yes SATELLITE 2 4 CRC32c Yes Note The pre-packaged parameters cannot be modified with the OYT command.Max.Retrans Check Sum Bundling 5 10 CRC32c Yes Summary of suggested parameter sets (cont. The SS7 parameter set is offered pre-tuned parameter for MTP3 like connection. It can be used with a connection between Nokia MSS and MGW. It should be remembered that the pre-defined parameter sets are only one example of possible combinations of the SCTP parameters. For this reason.Max. It is more feasible with data oriented application like www browsing. this parameter set is not the best choice in all cases where traditional TDM-based connection is replaced with signaling over IP system. This parameter set is designed to meet high performance requirements of MSC Server System. It should be remembered that in both peers this parameter set shall be used. IETF Path. The IETF parameter set is offered the RFC 2960 comliant parameters for SCTP stack. The General parameter set is designed for a case where Nokia system is used with the third party system.Retrans Assoc. Deactivate the association (OYS) or deactivate the association on association set one by one (OYS). When the capacity of the LAN is well-known and a better performance of recovery is required. Change the value of the parameters if the correct parameters to be modified and also the new values of these parameters are found.Signalling Transport over IP (M3UA and IUA) Note The values of the Path. create a new parameter set for this purpose. use the OYS command. 5.Retrans and Association. To modify the SCTP association level parameters. Check the value of the parameters (OYO).Retrans for all the destination addresses of the peer. ZOYE:TEST1:IETF:.Retrans parameter higher than the total sum of the values of Path. Current parameter values can be interrogated with the OYO command. 4. 70 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . To avoid this situation.Max.Max. the user should avoid setting the value of the Association. but careless configuration can lead an association to the state where all the destination addresses of the peer are unreachable (so called dormant state). but the peer stays in a reachable state. Change the parameter value with the OYT command. Change the parameter set of association set (OYM). the operator can tune how the SCTP association is wanted to be worked by using the SCTP association level parameters. SCTP parameter set of M3UA association set can be changed with the OYM command.Max. Change the value of the parameters (OYT).Retrans parameters can be configured independently. To deactivate the association. Create a new parameter set (OYE). 2. If you need to change the value of some SCTP parameters. 3. Modifying SCTP association level parameters 1. follow the steps below.Max. SCTP parameter set of the IUA connection can be modified with the OYW command. DN01141526 Issue 7-0 en # Nokia Siemens Networks 71 (81) .Modifying Sigtran parameters 6. Activate the association (OYS). Change the parameter set of association (OYW). 7. Activate the association or associations of association set by using the OYS command. Signalling Transport over IP (M3UA and IUA) 72 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en Deleting IP signalling links 11 11.1 Deleting IP signalling links This section describes how to delete the IP signalling links. Deleting M3UA signalling links Before you start Remove first the SCCP and MTP3 levels. For more information, refer to section Removing MTP signalling point in Common Channel Signalling (MTP, SCCP and TC). Steps 1. Delete the signalling link set (NSD). Delete the signalling link set with the NSD command. 2. Remove the unused association set (OYD). ZOYD:<association set name>; 11.2 Deleting IUA connections Steps 1. Delete the D-channels (DWD). Delete the D-channel with the DWD command. 2. Remove the unused association (OYD). ZOYD:<association set name>; DN01141526 Issue 7-0 en # Nokia Siemens Networks 73 (81) Signalling Transport over IP (M3UA and IUA) 74 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en Signalling transport over IP troubleshooting 12 12.1 Signalling transport over IP troubleshooting This section describes what to do in different error situations. IP signalling link activation fails The procedure for checking IP type signalling links is different from checking ordinary signalling links. Follow the procedure if you have not been able to activate the IP signalling link you have created, and the signalling link stays in the state UA-INS. For more information on the topic, refer to sectionSS7 troubleshooting in Common Channel Signalling (MTP, SCCP and TC). Steps 1. Check the alarms (AHO). a. Check the following alarms with the AHO command: 1273, 2069, 3156, 3159, and 3155. b. If there are any alarms, follow the alarm instructions. 2. Check the states and parameters of the association sets (OYI). For more information, refer to Modifying association set level parameters of M3UA. a. Check the states and parameters of the association sets with the OYI command. b. Check the SCTP level parameters. Checking is especially important in case of retransmission and also if the SCTP association goes down, but there is no LAN failure. 3. Check the signalling link parameter set and testing of links (NCI, NSI). DN01141526 Issue 7-0 en # Nokia Siemens Networks 75 (81) Check possible errors from the POSIX kernel log with the PKL command. or FlexiServer. The default value is 0. Check if the IP addresses of the local signalling unit are correct a. The default testing of the M3UA link set is denied. Check if the IP addresses of the local signalling unit are correct with the QRIcommand. 76 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . a. b. Add the POMOXIGX service terminal extension. You can use for example the letter P: ZLP:P. Check the signalling link parameter set with the NCI command. deny it with the NST command.Signalling Transport over IP (M3UA and IUA) Note You need to complete this step only if the far end of the link is another vendor's product or any of the following Nokia products: SCP. c. 3G-SGSN. b. Check the source IP addresses with the OYI command in case of M3UA connection problem. a. Check with the NSI command if the testing of the link set is denied. Check the static IP route configuration with the QKB command. c. Note Connect a service terminal to the correct computer unit. Check possible error counters to IP stack with the QRS command. 4.POM ZPKL 5. b. Check if source IP addresses of the association are correct. For example: ZQRS:<unit>::PRO. Change the value to 7 with the NCL command. Compare the IP addresses to the IP addresses assigned to the associations at the far end. SMSC. d. If it is not. Pay attention to the following possible sources of failure: . The last one is freeware software. a. 7. Monitoring a failed connection with some IP network analyzer.or IPA-based network element works as a client and a server comes from a third party. Check the possible SCTP bad checksum counters with QRS command. If tunnelled connection is used. Check the availability of the peer IP address with PING Check the availability of the peer IP address with PING by using the QRX command. Check IP network settings such as speed and duplex mode (these parameters will be the same in both ends of the link. Check the following alarms with the AHO command: 3159 DN01141526 Issue 7-0 en # Nokia Siemens Networks 77 (81) . . Check possible bottlenecks in the IP back bone. Check if correct checksum is used. . Check the router configuration and the site level LAN switch configuration. . 10. . 8. . Check the LAN cables and their connections. Check the LAN cables.Signalling transport over IP troubleshooting 6. 12. Check the IP network configuration. The default value is 1500 bytes. 9. By default between ESB and DX200-based network element use auto-negotiation mode). Check that the software version of routers and switches are compliant. Bandwidth limit or packet rate limit. Check from core IP routers if some bandwidth limits are set. MTU size.2 D-channel activation failed Steps 1. Check STP/RSTP/MSTP setting in the layer 2 network. Check the alarms (AHO). Checking whether correct checksum is used is especially important when the DX200. tuning the MTU size might be needed. Good monitoring tools are for example DPDUMP or some Ethernet monitoring tool. follow the alarm instructions. 78 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . refer to section IP signalling link activation fails. Check SCTP error counters and SCTP statistics (QRS). 5. For example: ZQRS:<unit>::PRO. c. 8. Check possible errors from the POSIX kernel log with the PKL command. d. Note Connect a service terminal to the correct computer unit. Check the IP network configuration. If there are any alarms. Check possible error counters to IP stack with the QRS command. Check if the IP addresses of the local signalling unit are correct a. 7. Add the POMOXIGX service terminal extension. You can use for example the letter P: ZLP:P. Check the LAN cables and their connections. b. Compare the IP addresses to the IP addresses assigned for the associations at the far end. Check the static IP route configuration. Check the state of association and source and destination IP addresses (OYV). 3. Check the LAN cables. For more information. Check the router configuration and the site level LAN switch configuration.POM ZPKL 6. 4. Check the availability of the peer IP address with PING Check the availability of the peer IP address with PING by using the QRX command. 2. Check if the IP addresses of the local signalling unit are correct by using the QRI command.Signalling Transport over IP (M3UA and IUA) b. Check the static IP route configuration with the QKB command. Check the LAN cables. follow the alarm instructions. Check the state of association and association set. If the configuration is correct but is still not working. Check the LAN cables and their connections. b.3 SCTP association failed Steps 1. 4. Check the IP network configuration. Check the D-channel configuration Check the D-channel configuration from both peers (MSS and MGW). If there are any alarms. Check the router configuration and the site level LAN switch configuration. 7.Signalling transport over IP troubleshooting 9. 3. Check the SCTP error counters and SCTP statistics (QRS). 5. Check the following alarm with the AHO command: 3159. Check the alarms (AHO). 12. a. Check the static IP route configuration. For more information. 2. Check the availability of the peer IP address with PING Check the availability of the peer IP address with PING by using the QRX command. Check the static IP route configuration with the QKB command. DN01141526 Issue 7-0 en # Nokia Siemens Networks 79 (81) . refer to section IP signalling link activation fails. 6. you can check the LAPD error counters from the MGW by using the DWN command. 3. Check the used SCTP parameters in both peers.4 Path of SCTP association failed Steps 1. b. 2.Signalling Transport over IP (M3UA and IUA) 12. If the SCTP parameters are different between peers. Check the availability of the peer IP address via failed path with PING Check the availability of the peer IP address with PING by using the QRX command. 4. 7. a. For more information. 6. refer to section IP signalling link activation fails. Check the value of the SCTP parameters with OYO command. b. Check the router configuration and the site level LAN switch configuration. Check the following alarm with the AHO command: SCTP_path_failure_a (3379). the following information will help to find out the root cause: 80 (81) # Nokia Siemens Networks DN01141526 Issue 7-0 en . Check the alarms (AHO). Check the state of association or associations set. Check the LAN cables and their connections. 5. the value of the SCTP parameters should be harmonized in both ends. Check the static IP route configuration. a. Check the static IP route configuration with the QKB command. If there are any alarms. 12.5 List of debugging commands in a failure case If the maintenance people cannot solve the failure by themselves and need to contact NSNs customer care. Check the LAN cables. follow the alarm instructions. 8. Check the SCTP error counters and SCTP statistics (QRS). Check the IP network configuration. DN01141526 Issue 7-0 en # Nokia Siemens Networks 81 (81) . 4.Signalling transport over IP troubleshooting 1. IP configuration (QRI) Static IP route configuration (QKB) SCTP association for M3UA (OYI) IUA configuration (OYV) SCTP parameters (OYO) SCTP error counters (QRS with ALL and PRO) DPDUMP monitoring or other monitoring from the ESB switches if possible. 7. 5. 2. 6. 3.