Direct Tunnel

WCDMA RANOne Tunnel Feature Parameter Description Copyright © Huawei Technologies Co., Ltd. 2011. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd. Trademarks and Permissions and other Huawei trademarks are the property of Huawei Technologies Co., Ltd. All other trademarks and trade names mentioned in this document are the property of their respective holders. Notice The purchased products, services and features are stipulated by the commercial contract made between Huawei and the customer. All or partial products, services and features described in this document may not be within the purchased scope or the usage scope. Unless otherwise agreed by the contract, all statements, information, and recommendations in this document are provided “AS IS” without warranties, guarantees or representations of any kind, either express or implied. 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Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd ............ 1-1 2 Overview ....6-1 7 Reference Documents .........2-1 3 Technical Description .........................................................................................................................................................................................................................................................................7-1 Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co................................................................................................................................................................................1 Parameters Description ...3 Change History...............5-1 6 Glossary ..........................WCDMA RAN One Tunnel Contents Contents 1 Introduction ...................................................... 1-1 1.....................................4-1 5 Counters .............2 Feature Impact and Requirements...................................................................... Ltd i ...........................................................................................................................................1 Scope .................................................................................. 3-2 4 Parameters ........................................................................ 3-1 3........................................................................................................................................................................................1-1 1................ 3-2 3...........................3-1 3...................................................................................................... 1-1 1...................................................................................................1 Overview ................................................................................................................................................2 Intended Audience ................................................................... 0. this issue optimizes the description. Ltd 1-1 . Compared with issue 01 (2010-03-30) of RAN12. 1. Editorial change: refers to the change in wording or the addition of the information that was not described in the earlier version. Draft A (2010-12-30) This is the draft of the document for RAN13. which are defined as follows:   Feature change: refers to the change in the One Tunnel feature. Compared with issue Draft A (2010-12-30) of RAN13. this issue optimizes the description.0.3 Change History This section provides information on the changes in different document versions.2 Intended Audience This document is intended for:    Personnel who are familiar with WCDMA basics Personnel who need to understand One Tunnel Personnel who work with Huawei products 1. this issue optimizes the description.0. Compared with issue Draft B (2011-03-30) of RAN13. There are two types of changes.. Document Issues The document issues are as follows:    01 (2011-04-30) Draft B (2011-03-30) Draft A (2010-12-30) 01 (2011-04-30) This is the document for the first commercial release of RAN13.WCDMA RAN One Tunnel 1 Introduction 1 Introduction 1. Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.0.0.1 Scope This document describes the principles of Huawei One Tunnel feature on the RNC side.0. Draft B (2011-03-30) This is the draft of the document for RAN13. processes both signaling traffic for example. the SGSN is still responsible for modifying the tunnel when the mobile device moves to an area served by another RNC. which has to terminate one tunnel. In 3G packet core architecture. For example. and then put it into the other tunnel. extract the packet.WCDMA RAN One Tunnel 2 Overview 2 Overview The specification of One Tunnel (direct connection between RNC and GGSN) is a part of 3GPP Release 7. to keep track of a user's location and the actual data packets exchanged between the user and the Internet. The current architecture uses one tunnel between the GGSN and the SGSN and the other one between the SGSN and the Radio Network Controller (RNC). Since the user's location may change at any time.. Ltd 2-1 . This requires both time and processing power. the SGSN can set up a direct tunnel between the RNC and the GGSN and thus remove itself from the chain. data packets are tunneled (encapsulated) from the Gateway GPRS Support Node (GGSN) to the Internet through the SGSN over the radio network to the mobile device. The one tunnel feature has the following advantages:    Reducing a majority of SGSN user plane resource investment and thus reducing CAPEX and OPEX for operators Shortening the delay and thus improving customer experience Supporting expansion of the user plane with upgrade of only the GGSN and the RNC and thus improving the network expansibility Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. All data packets thus have to pass the SGSN. Mobility management remains on the SGSN. which is the gateway between the radio network and the core network. the Serving GPRS Support Node (SGSN). With one tunnel approach. With one tunnel approach. Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.1 Overview The one tunnel feature (WRFD-020111 One Tunnel) improves efficiency for PS traffic. It avoids the SGSN to be the bottleneck of the network when high PS traffic occurs. One tunnel is located between the GGSN and the SGSN. This requires both time and processing power.. Figure 3-2 shows the user plane protocol stack in the one tunnel scenario. which extracts packets of one tunnel and puts it into the other tunnel. Figure 3-1 shows the user plane protocol stack in the two-tunnel scenario. Figure 3-2 User plane protocol stack Figure 3-3 shows the data transmission of one tunnel and two tunnels.WCDMA RAN One Tunnel 3 Technical Description 3 Technical Description 3. in which the control plane protocol stack remains the same. Figure 3-1 User plane protocol stack Since both the RNC and the GGSN are IP routers. and the other between the SGSN and the RNC. the SGSN can create a direct tunnel between the RNC and the GGSN and thus remove itself from the chain. The preexistent architecture of 3G packet core uses two tunnels. All data packets thus have to pass the SGSN. Ltd 3-1 . this process (the SGSN extracts packets of one tunnel and puts it into the other tunnel) is not required in most circumstances. 1. and the RNC. Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. The RNC initiates the RAB release procedure with the error cause value GTP Resources Unavailable.060 13. the following NEs or interfaces may have new functions or new information elements (IEs):  SGSN − The DTI field in the PDP context is used to indicate whether one tunnel is supported. TS23. that is. 3. RNC − Support − Manage  Error Indication messages. For example. In the case of one tunnel. Radio Network Layer Cause Extension.8.WCDMA RAN One Tunnel 3 Technical Description Figure 3-3 Data transmission of one tunnel and two tunnels Mobility management remains on the SGSN. 3. The RNC also triggers the Local Connection Release immediately without waiting for the response from the SGSN.1 Parameters Description To support the one tunnel configuration.413 9. the RNC only needs to meet the following requirements:   The RNC follows the GTP-U error handling procedure regardless of the GTP-U Error indication from the SGSN or GGSN. the SGSN is still responsible for modifying the tunnel when the mobile device moves to an area served by another RNC.4 adds the error cause value GTP Resources Unavailable (263) to the IE. Ltd 3-2 .2.2 Feature Impact and Requirements The one tunnel feature requires the support from the GGSN..  Gn − Add DTI information to the Update PDP Context Request. − Determine  GGSN The DTI field in the PDP context is used to indicate whether one tunnel is supported. the SGSN.  For the configuration and reconfiguration. TS25. the paths between the GGSN and the RNC.3 defines the GGSN fault and the procedure when the RNC receives a GTP error indication. whether to establish one tunnel. a new parameter SGSNFLG is added in the ADD ADJNODE command. The Update PDP Context Request contains the error information. The number of signaling points. however. remains the same. Iu − Replace − Add Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. however.. The number of signaling points. GGSN sends the Update PDP Context Request to the SGSN during the Error Indication procedure.WCDMA RAN One Tunnel − Replace − Add − The  3 Technical Description the SGSN user plane address of the Update PDP Context Request with the RNC user plane address. Ltd 3-3 . remains the same. Error Cause (GTP Resources Unavailable) to the RAB Release Request. GCSI information to the Forward Relocation Request for CAMEL service indication. the SGSN user plane address of the RAB Assignment Request with the GGSN user plane address. . A parameter value YES indicates that the BSC6900 is connected to a SGSN. YES(SGSN) Actual Value Range:NO. This parameter is valid when the node type is set to IUPS.WCDMA RAN One Tunnel 4 Parameters 4 Parameters Table 4-1 Parameter description Parameter ID SGSNFLG NE BSC6900 MML Command ADD ADJNODE(Mandatory) Description Meaning:This parameter specifies whether the BSC6900 is connected to a SGSN or a GGSN. A parameter value NO indicates that the BSC6900 is connected to a GGSN GUI Value Range:NO(GGSN). YES Default Value:None Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. Ltd 4-1 . Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.WCDMA RAN One Tunnel 5 Counters 5 Counters There are no specific counters associated with this feature.. Ltd 5-1 . see the Glossary. Ltd 6-1 . abbreviations. and definitions.. terms.WCDMA RAN One Tunnel 6 Glossary 6 Glossary For the acronyms. Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co. 060 Service description [2] 3GPP TS25.WCDMA RAN One Tunnel 7 Reference Documents 7 Reference Documents [1] 3GPP TS23. Ltd 7-1 ..413 UTRAN Iu interface RANAP signalling Issue 01 (2011-04-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.