Design Design

Manasa M S

, IJRIT 249

International Journal of Research in Information Technology (IJRIT)

Design

Design Design

Design and and and and Development of PMIP Codec and LMA Development of PMIP Codec and LMA Development of PMIP Codec and LMA Development of PMIP Codec and LMA Procedures for Network Based Localized Mobility Procedures for Network Based Localized Mobility Procedures for Network Based Localized Mobility Procedures for Network Based Localized Mobility

Management Management Management Management

Manasa M S¹, Shivamurthy R C²

1Student, CS & E, Akshaya Institute of Technology, VTU Tumkur, Karnataka, India

[email protected]

2Professor, CS & E, Akshaya Institute of Technology, VTU Tumkur, Karnataka, India

[email protected]

Abstract

Abstract— Mobility of handheld devices for which IP address can be assigned is a hot topic from last few years. This trend has fostered the business case in 3G/4G/LTE mobile communication networks. Many standardization bodies namely IETF, IEEE and 3GPP are working together in improving the mobility experienced by users. Existing IP mobility solution protocols such as Mobile IPv4 or Mobile IPv6 are terminal based, meaning the terminals are aware of their mobility and have to do operations in order to be able to maintain their ongoing communication sessions. Proxy Mobile IP specifications provide localized mobility support without relying on mobility functionality present on mobile nodes. PMIP protocol is designed to provide rich mobility experience by providing efficient handover mechanisms.

PMIP is network based mobility protocol to achieve IP mobility operations without involving mobile node at all. It provides mobility support within localized area by adding two logical entities to IP network namely Mobile Access Gateway (MAG) and Local Mobility Anchor (LMA). This paper describes understanding of PMIP protocol procedures, design and development of codec for PMIP messages involving in connection establishment, connection teardown and heart beat mechanism procedures. The procedures are considered from LMA point of view. Also implementation procedures in LMA node under Linux operating system environment are described.

Keywords: PMIP, LMA, MAG, 3GPP, WLAN

1. Introduction

In last few years there has been an explosive growth both in the number of laptop, notebook computers and nodes connected to the internet and World Wide Web. The notebook computers are themselves powerful, equal in processing capability to desktop workstations. The future of internet is likely to be fueled in large by these notebook computers. Along with these trends, there has also been steady growth in the market of wireless communication devices. These trends are motivating a great deal of interest in making the sure that mobile wireless computers can attach to the internet and remain attached to the internet even as they move from place to place, establishing new links. Mobile IP protocol was the first such protocol to provide seamless roaming to the mobile computers in the internet. The current trend is towards network-based solutions where mobility support is based on network operation.

Proxy Mobile IPv6 is a promising specification that allows network operators to provide localized mobility support without relying on mobility functionality or configuration present in the mobile nodes, which greatly eases the deployment of the solution[1]. This paper describes protocol implementation starting from codec to LMA procedure design and their development to provide mobility management functionality.

Manasa M S

, IJRIT 250 1.1 Objective

The Proxy Mobile IP[1,2] is a network based mobility management protocols standardized by IETF. It is protocol for building a common and access technology independent of mobile core networks, accommodating variety of access technologies such as WiMAX, 3GPP and WLAN based access architectures [3]. The main objective of this project includes understanding the procedures involved in PMIP procedures and implementing the procedure of one of the PMIP network nodes Local Mobility Anchor which is communicating with Mobile Access Gateway for signaling establishment, teardown and data flow between mobile nodes to internet.

1.2 Network Nodes of PMIPv6

There are two functional entities of PMIPv6 architecture [3,4] which are mentioned below,

• Mobile Access Gateway (MAG) - This functional entity takes care of mobility related signaling on behalf of mobile node which is attached to access links and it is also responsible for tracking the movements of mobile nodes in localized mobility domain.

• Local Mobility Anchor (LMA) - This entity is the anchor for the addresses used by the MNs in the LMD. It stores all the routing information needed to reach each of the MNs in the corresponding LMD by associating the MN with the MAG that the MN is using. A tunnel between the LMA and the MAG an MN is using allows the transfer of traffic from and to the MN.

2. Problem Statement and Solution

Mobile IP solution which were developed earlier has problems as mentioned below,

• Clients (Mobile Nodes) must implement MIP in kernel leading to difficulty in implementing and deployment.

• Handoff procedures are not efficient as there are large delays.

• Security concerns as MIP support in the kernel adds an additional vendor attack.

Proxy Mobile IPv6 was thought of to provide solution to the problems faced in MIP. PMIPv6 provides solution with the following approach,

• PMIP is completely transparent to mobile nodes as PMIP network nodes MAG and LMA will take care of signaling procedures.

• PMIP is meant to be used in localized networks with limited topology where handoff signaling delays are minimal.

• Ease of deployment of PMIP solution as network nodes will take care of signaling on behalf of MN.

• Efficient handoff procedures were provided by PMIP domain as there is no need of communicating to Home Agent as in MIP to reach the cloud.

3. Connection Establishment and Handoff Procedures

Connection establishment procedure in the PMIP localized mobility domain is shown in Fig 1. When mobile node connects to an LMD it sends a standard router solicitation. The access router in PMIP domain MAG will perform all mobility related signaling on behalf of MN. The MAG sends to the LMA a Proxy Binding Update (PBU) associating its own address with the identity of the Mobile Node (Media Access Control [MAC] address of UE may be used of identifier). On receiving PBU LMA allocates a prefix/ip address to the Mobile Node. Then the LMA sends to the MAG a Proxy Binding Acknowledgment (PBA) including the prefix allocated to the Mobile Node [3]. It also creates a Binding Cache entry and establishes a bidirectional tunnel to the MAG.

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, IJRIT 251

Handoff procedures are briefed in Fig 2 when mobile node moves from one MAG to other MAG within the same LMD. The new MAG has to use, when communicating to the MN, the same IPv6 link-local and link layer address of the previous MAG to avoid the MN detecting a change of access router [5, 6].

MN MAG LMA

MN Attached Event from MN/Network (Acquire MN-Id and Profile)

Rtr sol

PBU

Accept PBU (Allocate IP(s), Setup BCE and Tunnel)

PBA

Accept PBA (Set Up tunnel and Routing) MN Attached

Rtr Adv

IP Address Configuration

Bi-Dir Tunnel

Fig. 1 Connection Establishment Procedure

MN MAG1 LMA MAG2

MN Detached

Bi Directional Tunnel

MN Detached Event

DeReq PBU

Accept PBU (Start min delay Before BCE

Delete Timer)

PBA

MN Attached

MN Attached event received from MN or from network (Acquire MN-Id and Profile)

Rtr Sol

Bi Directional Tunnel

Rtr Adv MN retains HOA/HNP(s)

Fig. 2 Handoff Procedures

Manasa M S

, IJRIT 252 4. System Design

Module representation of PMIP nodes (MAG or LMA) is shown in Fig 3. PMIP codec is a code capable of encoding or decoding of a digital data. PMIP codec is developed as a dynamic library under Linux, which could be used by application developer for encoding and decoding of Proxy Mobile IP messages. Standard port 5436 is used for communicating signaling messages between LMA and MAG.

Fig. 3 PMIP Module representation

4.1 Design considerations for PMIP codec

Following considerations are done for the development of PMIP codec,

• Codec should be developed, compiled and kept as dynamic library, so that any PMIP application should link to the library and use it for encoding and decoding of PMIP messages.

• Encoding and decoding of following PMIP messages shall be supported, a. Proxy Binding Update (PBU)

b. Proxy Binding Acknowledgement (PBA) c. Binding Revocation Indication (BRI)

d. Binding Revocation Acknowledgement (BRA) e. Heart Beat Request and Heart Beat Response

• Codec should be developed considering rules defined in rfc3775, rfc5213, rfc5844, rfc 5846 and their related rfc’s.

• Application Programming Interface (API) should be exposed to the user for encoding and decoding.

4.2 LMA Module procedure design

Following are features which are part of LMA network node implementation,

• Threads to handle different operations of LMA module.

• Maintaining IP pool, allocating and de-allocating based on messages from MAG. Also maintaining binding state per MNID for the session established in the context.

• Initialization with default configuration.

• Support for commands at LMA at Client Console to modify parameters and to send binding revocations.

• Statistics support to see the behavior of LMA during higher loads and traffic analysis.

• Timer handling during session establishment and tear down.

Manasa M S

, IJRIT 253 4.3 Flowchart Representation of LMA procedures

This section describes LMA procedures using flowchart. Fig 4 to Fig 8 has different procedures ranging from MAG verification; different message handling and heart beat mechanism.

Fig. 4 Flowchart representing MAG verification and decode procedure

Fig. 5 Flowchart representing PBU handling representing

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, IJRIT 254

If the BR type of the message with MH type 16, then message is considered to be Binding Revocation which can be BRI or BRA based on revocation type. Fig 6 and Fig 7 represents flowchart for BRI and BRA message handling.

Fig. 6 Flowchart representing BRI handling

Fig. 7 Flowchart representing BRA handling

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, IJRIT 255

If the MH type received is 13, then heart message is considered to be received, which is represented in as flowchart in Fig 8.

Fig. 8 Flowchart representing Heart Beat Message handling

4.4 Hardware and Software Requirements

Following are hardware and software requirements for development of Proxy Mobile IP codec and Local mobility Anchor procedures.

Hardware requirement includes Intel dual core processor. Since module will be developed with multithreaded processing system will perform well under multi-core environment.

Software Requirements are as follows,

• Linux Operating System, preferably Ubuntu/Cento OS flavor.

• Language requirement of C and C++

• Compiler version of gcc and g++ with 3.26 version onwards

• Building tools such as Makefile

• Scripting language – shell scripting

• Packet Analyzer – Wireshark

5. Testing and Results

Snapshot shown in Fig 9 below shows the home window when Codec Test application is ran. This has options to encode and decode different messages as shown in the snapshot. User can type different sequence numbers to test supported messages of codec. Snapshot shown in Fig 10 shows the home screen when LMA module is ran. Simulator is run by executing a “Run” scripts available. This file is a shell script used to start the LMA module, which internally executes LMA executable. Snapshot shown in Fig 11 has information on flat file configuration items for LMA module.

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, IJRIT 256

Fig. 9 Snapshot of Home page of Codec Test App

Fig. 10 Snapshot of Home page of LMA Module

Fig. 11 Snapshot of Initial Configuration settings

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, IJRIT 257

Snapshot in Fig 12 shows MAG simulator options to send simulated message to LMA. One can send different messages to LMA. Snapshot in Fig 13 shows hex dump of decoded PBU message at LMA module. This is to check whether the messages sent by MAG are received and message is decoded properly.

Fig. 12 Snapshot of Home page of MAG Simulator Home screen

Fig. 13 Snapshot of hex dump of decoded PBU message

Fig 14, Fig 15 and Fig 16 shows wireshark capture of PBU, PBA exchange; BRI, BRA exchange and Heart Beat Message exchange

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, IJRIT 258

Fig. 14 Snapshot of wireshark showing PBU and PBA message exchange

Fig. 15 Snapshot of wireshark showing BRI and BRA message exchange

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, IJRIT 259

Fig. 16 Snapshot of wireshark showing HB Request and Response message exchange

6. Application of PMIP protocols

Following are the target scenarios where PMIP protocol is used,

• Wireless LAN accessed Large Campus Networks where user with IP standard devices will move within the campus.

• Shared corporate networks where there is agreement between companies and registered user moves from one corporate network to other corporate network.

• Large Stadiums with WLAN deployment.

• Shopping malls with WLAN deployment.

• Advanced beyond third generation networks with cellular operators being important promoters of PMIP based Network Based Local Mobility Management solution. UMTS and GPRS networks use proprietary NetLMM mechanism to provide mobility support for user data traffic.

7. Conclusion

Telecommunication operators are pushing for the standardization of network-based localized IP mobility support solutions. These solutions allow them to offer mobility support in their IP networks without depending on functionality or mobility related configuration in user terminals.

PMIP is the base protocol standardized by the IETF to provide network-based localized mobility support in IP networks. Both the research community and different standardization bodies – mainly the IETF – are

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, IJRIT 260

working on additional features to enhance the possibilities of using PMIPv6, including flow mobility, multicast support and network mobility support.

PMIP and its potential extensions are being positioned as the solution of choice to provide mobility support in IP networks. The inherent benefits of using PMIP and, the interest and value of the additional proposed features allow us to envision a significant impact of these technologies in future operator networks.

References

[1] S. Gundavelli, K. Leung, V. Devarapalli, K. Chowdhury, and B. Patil, “RFC 5213 - Network Working Group Request for Comments - Proxy mobile IPv6”, August 2008

[2] D. Johnson, C. Perkins, and J. Arkko, “Mobility Support in IPv6,” IETF RFC 3775, June 2004.

[3] Carlos J. Bernardos, Marco Gramaglia, Luis M. Contreras, Network-based Localized IP mobility Management: Proxy Mobile IPv6 and Current Trends in Standardization 2010.

[4] J. Kempf. Goals for Network-Based Localized Mobility Management (NETLMM). RFC 4831, April 2007

[5] Yuh-Shyan Chen, Springer, Editorial Special Issue on “Advances in Mobile IPv6 and Network-Based Localized Mobility Management Science+Business Media, LLC. 2011

[6] J. Laganier and S. Narayanan, “Network-Based Localized Mobility Management Interface Between Mobile Node and Mobility Access Gateway,” IETF Internet draft, draft-ietfnetlmm-mn-ar-if-02, May 2007

[7] W. Stallings. Mobile IP. The Internet Protocol Journal, 4(2):2–14, June 2001