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Dynamic Management of Multiple Mobile Routers

Manabu Tsukada, Thierry Ernst, Ryuji Wakikawa and Koshiro Mitsuya

Graduate School of Media and Governance, Keio University

13th IEEE International Conference on Networks (ICON), Jointly held with 7th IEEE Malaysia International Conference on Communication, 2005, pp. 1108-1113.

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Outline

• Introduction• Issues and Approach• Overview of Multiple Mobile Router Management

(MMRM)• Implementation• Evaluation• Conclusion

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Introduction

• Network mobility support is necessary for a group of computers moving together and requiring access to the Internet, – such as a network of sensors or access networks deployed in

vehicles.

• The overall bandwidth can be increased and redundancy can be provided by serving the mobile network through multiple mobile routers. – However, this raises a number of issues related to multihoming.

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• Problems:– MNNs do not know that an

additional Internet connectivity, through another MR, is available

– MNNs are not allowed to switch between MRs without breaking on-going session

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Introduction (cont.)

• In this paper, we propose a Multiple Mobile Router Management (MMRM) system which – allows a mobile network to be served through multiple MRs

• allows MRs to dynamically join and leave

– transparent to the MNNs.

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the NEMO Basic Support protocol (RFC3963)

• Establish a bi-directional tunnel between the mobile router (MR) in the vehicle and a home agent (HA) in the fixed infrastructure. – The MR serves as a gateway for the nodes located inside the

vehicle (mobile network nodes or MNNs)

• All packets intended to or originated from the MNNs are encapsulated into the tunnel established between the MR and the HA.

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• The MR’s current location (the point of attachment of the vehicle) is determined by the Care-of Address (CoA) acquired on the egress interface of the MR.

• A permanent address, called the Home address (HoA) and obtained on the MR’s home link, is also acquired on the same interface and used as an identifier.

• All MNNs configure an address taken from a permanent prefix (Mobile Network Prefix or MNP) assigned to the mobile network.

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Mobile Node attached to Mobile Router on a visited link

vehicle [*] V. Devarapalli, R. Wakikawa, A. Petrescu et al., "Network Mobility (NEMO) Basic Support Protocol," IETF RFC 3963, 2005.

MR’s HoA

MR’s CoA

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Issues and Approach

• generic goals and benefits of multihoming [6]– Permanent and Ubiquitous Access– Reliability– Load Sharing and Load Balancing– Preference Settings– Aggregate Bandwidth

[6] C. Ng, T. Ernst, E. Paik et al., "Analysis of Multihoming in Network Mobility Support," IETF RFC 4980, 2007.

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Issues and Approach (cont.)

• Multiple Paths Establishment– multiple bi-directional tunnels– extend the use of the Multiple Care-of addresses Registration

(MCoA) scheme• Binding Unique Identification number (BID)

– distinguish multiple bindings registered by a single mobile node and corresponding to the same HoA

• Path Selection– The MR/HA should be able to select the path for packets

from/to the mobile network• 若交由MNN自行選擇 default router將需要修改MNN

– 由MRs coordinate

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• Session Preservation– when one tunnel fails, the path must be changed without

breaking on-going sessions and transparently to the MNNs.– establish a bi-directional tunnel between the primary MR and

non-primary MR

• Dynamic State Sharing– In order to allow MRs to join/leave the mobile network, a

dynamic state sharing scheme is needed.– MRs exchange binding information

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Overview of MultipleMobileRouterManagement

• Primary Mobile Router (PMR)– acting as a default router for MNNs– gathering policies– has the responsibility for path selection

• non-Primary Mobile Router (non-PMR)– simply forwards packets from the PMR to HA.

• Neighbor Egress interface List (NEL): – Maintained by both the PMR and non-PMRs– contains an entry for every binding that the multiple MRs have.

• NEL Advertisement– advertised on the ingress interfaces– to synchronize NELs between MRs

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• Message sequence

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• The extended MCoA scheme

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• The routing process

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Evaluation

10BASE-T

100BASE-T

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Overhead Measurement

• For the RTT measurement, MNN sends 56-Byte ICMPv6 Echo Request packets to CN 100 times.

• For the throughput measurement, MNN sends TCP packets to CN for 5 minutes.– The packet size is 1208 bytes.

This overhead must be balanced against the complexity and cost to extend all MNNs with path selection mechanisms.

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Flow distribution

• MNN establishes three TCP sessions to CN, – port numbers 5001, 5002 and 5003 for Ethernet links (A), (B) and (C)

respectively.

• time t=0~300 second, link (B) and (C) were disconnected – all the three sessions pass through the same link (A)

• t=300~600 second, all three links (A), (B) and (C) were connected– all the three sessions from MNN to CN pass through three distinct link

• The throughput was measured every 3 seconds for 600 seconds.

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• MMRM change the path without breaking on-going sessions and to distribute traffic as soon as multiple paths become available

avg.1086 Kbps

avg.2586 Kbps

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Conclusion

• the Multiple Mobile Routers Management (MMRM) system 1) multiple CoAs registration from MRs2) cooperation between MRs3) traffic separation from MNNs to CNs– allow MRs to dynamically join into and leave from a mobile

network• dynamically share the Internet connectivity, and to increase the overall

bandwidth

– increases the redundancy and the bandwidth for MNNs by separating the traffic to multiple path

– transparently change the path for applications on MNNs

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• MMRM system does not yet allow MNNs to communicate with CNs when PMR is down.– A non-PMR does not know if a PMR is down, or leaves from the

mobile network by removing a corresponding NEL entry, – but HA knows it from the binding update.

• allow the HA to select an alternative PMR.

• Security between HA and MRs will be provided by the Security Association (SA)

• For security between MRs, transport mode IPsec can be used to protect NEL advertisements.

• SEcure Neighbor Discovery (SEND) can provide security between MRs and MNNs.

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comments

• Multiple network interface

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Multihoming issues [6]• Fault Tolerance

– Failure Detection– Path Exploration– Path Selection– Re-Homing

• Ingress Filtering• HA Synchronization• MR Synchronization• Prefix Delegation• Multiple Bindings/Registrations• Source Address Selection• Loop Prevention in Nested Mobile Networks• Prefix Ownership• Preference Settings[6] C. Ng, T. Ernst, E. Paik et al., "Analysis of Multihoming in Network Mobility Support," IETF RFC 4980, 2007.