Integrating Tcpip Interfaces_sg5_final

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2G SGSN SG5 OM

Integrating TCP/IP Interfaces in 2G SGSNConfiguration and Integration

Nokia Networks Oy

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Integrating TCP/IP Interfaces in 2G SGSN

The information in this document is subject to change without notice and describes only the product defined in the introduction of this documentation. This document is intended for the use of Nokia Networks' customers only for the purposes of the agreement under which the document is submitted, and no part of it may be reproduced or transmitted in any form or means without the prior written permission of Nokia Networks. The document has been prepared to be used by professional and properly trained personnel, and the customer assumes full responsibility when using it. Nokia Networks welcomes customer comments as part of the process of continuous development and improvement of the documentation. The information or statements given in this document concerning the suitability, capacity, or performance of the mentioned hardware or software products cannot be considered binding but shall be defined in the agreement made between Nokia Networks and the customer. However, Nokia Networks has made all reasonable efforts to ensure that the instructions contained in the document are adequate and free of material errors and omissions. Nokia Networks will, if necessary, explain issues which may not be covered by the document. Nokia Networks' liability for any errors in the document is limited to the documentary correction of errors. Nokia Networks WILL NOT BE RESPONSIBLE IN ANY EVENT FOR ERRORS IN THIS DOCUMENT OR FOR ANY DAMAGES, INCIDENTAL OR CONSEQUENTIAL (INCLUDING MONETARY LOSSES), that might arise from the use of this document or the information in it. This document and the product it describes are considered protected by copyright according to the applicable laws. NOKIA logo is a registered trademark of Nokia Corporation. Other product names mentioned in this document may be trademarks of their respective companies, and they are mentioned for identification purposes only. Copyright Nokia Networks Oy 2005. All rights reserved.

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Contents

Contents1 2 3 3.1 3.1.1 3.2 3.2.1 3.3 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 4 4.1 4.1.1 4.1.2 4.2 4.3 4.3.1 4.4 4.5 5 5.1 5.2 5.2.1 5.3 5.4 5.4.1 5.4.2 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Objectives................................................................................... 4 Introduction ................................................................................ 5 Protocol stacks .......................................................................... 7 Gn interface ................................................................................. 7 GPRS Tunneling Protocol (GTP) ................................................. 7 Gb interface ................................................................................. 8 Gb over IP load sharing ............................................................... 9 SS7 over IP (SIGTRAN) interfaces ............................................ 11 M3UA ......................................................................................... 12 SCTP ......................................................................................... 12 Association sets and associations ............................................. 13 SGP-ASP communication.......................................................... 13 Basic Configurations of SS7 signalling over IP .......................... 14 Integration ................................................................................ 16 Configure network interfaces ..................................................... 16 Redundant interfaces................................................................. 16 Physical and logical IP addresses ............................................. 17 Create routes ............................................................................. 18 Gn interface configuration.......................................................... 19 Create domain name server ...................................................... 19 Gb over IP configuration ............................................................ 20 SS7 over IP configuration .......................................................... 20 Session Management .............................................................. 22 PDP Context Activation.............................................................. 23 PDP Context Deactivation procedure ........................................ 27 PDP context deactivation initiated by MS .................................. 28 PDP Context Modification procedure ......................................... 29 Exercises ................................................................................... 29 Define IP interface parameters .................................................. 29 Activate a PDP Context ............................................................. 30 QoS Quality of Service ......................................................... 31 QoS Mapping ............................................................................. 32 ARP support in admission control .............................................. 35 Operator configurable DiffServ Codepoints ............................... 35 Weighted Far Queuing (WFQ) and Random Early Detection (RED)......................................................................... 36 Service-based QoS control ........................................................ 37 Secondary PDP contexts ........................................................... 38 TCP Optimisation ....................................................................... 39

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Integrating TCP/IP Interfaces in 2G SGSN

1

ObjectivesAfter this session the participant should be able to: Describe the TCP/IP protocol stack used by the 2G SGSN Configure the Gn interface Configure the Gb interface over IP Configure the SS7 interfaces over IP List Session Management procedures Explain QoS and related parameters in Nokia 2G SGSN With reference to any documentation.

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Introduction

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IntroductionNokia 2G SGSN gives the operator the option of implementing any of its interfaces over an IP network. Each computer unit includes an IP protocol stack, and therefore they can be individually configured to act as an IP host or IP router. The units can be connected to each other via LAN, and every unit includes a redundant network interface. Since Release SG3 of Nokia 2G SGSN there is also the option to configure the SS7 and Gb interfaces over IP. Both interfaces were already described in previous modules. This module describes only the IP transmission option for these interfaces. Gn and Ga interface are originally IP-based interfaces. The Gn interface allows the SGSN to communicate with other GPRS Support Nodes (GSNs) via the IPbased GPRS backbone (Figure 1). The main connection is to the GGSNs that offer access to external data networks. In addition, connections are also needed to other SGSNs to support inter-SGSN routing area updates, for instance. The Gn interface is used for both transmission of user packet data and for the signalling needed in mobility and session management support between the GSN elements. Ga interface will be covered in module Integrating Ga interface.

Figure 1.

Gn interface location

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Integrating TCP/IP Interfaces in 2G SGSN

A LAN Unit (LANU) is introduced in Release SG5. Each LANU contains two ESB26 switches where the redundant Ethernet interfaces connect. More about LANU can be found in module SGSN Architecture.

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Protocol stacks

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Protocol stacks

3.1

Gn interface

Figure 2.

Gn protocol stack

Figure 2 illustrates the Gn protocol stack. It consists of the following layers: Layers 1 & 2, compliant with Ethernet standards 10BaseT or 10BaseTX Internet Protocol version 4 (IPv4) or version 6 (IPv6) User Datagram Protocol (UDP) GPRS Tunnelling Protocol (GTP).

3.1.1

GPRS Tunneling Protocol (GTP)The GPRS Tunneling Protocol (GTP) is the protocol used between GPRS Support Nodes (GSNs) in the UMTS/GPRS backbone network. Nokia 2G SGSN supports both versions of GTP: GTPv0 and GTPv1. Among other differences, GTPv1 procedures are separated: GTP control plane (GTP-C) and data transfer (GTP-U) procedures. GTP (GTP-C and GTP-U) is defined for the Gn interface, i.e. the interface between GSNs within a PLMN. GTP allows multi-protocol packets to be tunneled through the UMTS/GPRS Backbone between GSNs. In the control plane, GTP specifies a tunnel control and management protocol (GTP-C) which allows the SGSN to provide packet data network access for an MS. Control Plane signalling is used to create, modify and delete tunnels. In the user plane, GTP uses a tunneling mechanism (GTP-U) to provide a service for carrying user data packets.

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Integrating TCP/IP Interfaces in 2G SGSN

In GPRS no other systems need to be aware of GTP. UMTS/GPRS MSs are connected to an SGSN without being aware of GTP. Nokia 2G SGSN implementing GTP protocol version 1 is able to fallback to GTP protocol version 0.Control plane (GTP-C)

The control plane relates to GPRS Mobility Management functions like for example GPRS Attach, GPRS Routing Area Update and Activation of PDP Contexts. The GPRS Tunneling Protocol-Control plane (GTP-C) performs the control plane signalling between GSN nodes. The GTP-C control plane flow is logically associated with, but separate from, the GTP-U tunnels. For each GSN-GSN pair one or more paths exist. One or more tunnels may use each path. GTP-C shall be