Subject: [nemo] Multi-homing using NEMO

From: Ken Nagami <[email-masked]>
Date: Thu, 26 Feb 2004 13:10:36 +0900

Hi all,

We are interested in multi-homed network using NEMO.
Currently, we implemented the following architecture and evaluate in a
experimental network.

Attached document is our motivation and idea for multi-homing using NEMO.
Since I did not submit by deadline as I-D, I send this draft to NEMO ML.

I think some of them is merged into scenario or problem statement draft
for multi-homing.

If you have any comment or questions, please let us know.

Regards,

Ken Nagami

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   Multi-homing for small scale fixed network Using Mobile IP and NEMO

                                            Kenichi Nagami(INTEC Netcore)
                                                      Satoshi Uda (JAIST)
                                                   Nobuo Ogashiwa (JAIST)
                                               Ryuji Wakikawa(Keio Univ.)
                                               Hiroshi Esaki(Univ. Tokyo)
                                                    Hiroyuki Ohnishi(NTT)

Abstract

    Multi-homing technology improves the availability of host and network
    connectivity. Since the node and network behavior of mobile
    networking and fixed networking are different, the different
    architecture has been discussed and proposed. This document proposes
    the common architecture both for mobile and fixed networking
    environment, using the mobile IP and NEMO. The proposed architecture
    only requires a modification of the mobile IP and NEMO so that
    multiple-CoA can be used. In addition, multiple HAs which are located
    in different place, are required for redundancy.

1. Motivation

    Users of small scale network need to improve the network availability
    and to get load balance of several links by easy method. Multi-homing
    technology is one of solutions to improve the
    availability. Conventional major multi-homing network uses BGP. But
    it has some issues as followings. Therefore, we propose a
    multi-homing architecture using the mobile IP and NEMO for
    small-scale fixed network.

    (1) Increasing route entries in the Internet

       In the multi-homing environments, each user's network needs to
       advertise its address block to all ISPs connected to them. If
       multi-homed user connects only one ISP, the ISP can advertise
       routing information to aggregate them. But some multi-homed user
       needs to connect with different ISPs in preparation for failure of
       ISP. In this case, ISPs need to advertise routing information for
       multi-homed user without aggregation. Therefore, the number of
       routing entries in the Internet is increasing one by one.

    (2) Difficulty to efficiently use multiple links

       It is not easy to control in-coming traffics in the case of the
       conventional multi-homing architecture using BGP. Therefore, load
       balancing of connected links are difficult.

2. Multi-homing for small scale fixed network Using Mobile IP and NEMO
2.1 Mobile network includes fixed network

    NEMO and Mobile IP must work with multi-homing by its nature. This is
    because mobile nodes need to use multiple links for improving the
    availability of network connectivity since the wireless link is not
    always stable. Therefore, we propose that multihoming for fixed nodes
    (routers and hosts) use the framework of NEMO and Mobile IP.

2.2 Overview multi-homing network architecture using Mobile IP

    Figure 1 shows basic multi-homing network architecture. In this
    architecture, a mobile router (MR), which is boarder router of
    multi-homed network, sets up several tunnels between the MR and the
    HA by multiple-CoA registration to provide redundancy and load
    balancing. A HA or a router which the HA belongs advertise user's
    network prefix to ISPs via routing protocol. If HA has several
    multi-homed network, they can advertise an aggregated network prefix
    to ISPs. Therefore, the Internet routing entries do not increase one
    by one when multi-homed user is increased.

    Packets to multi-homed users go to HA and the HA sends packets to MR
    using CoA1 and CoA2. The HA select a route which CoA is used. The
    route selection algorithm is out of scope of this document. This can
    improve availability of user network and control an in-coming traffic
    between ISP and MR. In the basic architecture, HA1 is single point of
    failure. In order to improve availability of user network, multiple
    HA is needed. This is described in later section.

           HA1
            |
           ISP A--ISP B
               |   |
           CoA1|   |CoA2
            Mobile Router (MR)
                 |
             Multi-homed
             user network

      Fig.1 Basic Architecture

3. Requirements for Mobile IP and NEMO
3.1 Multiple Care-of-Addresses (CoA)

    Multiple Care-of-Addresses needs to improve the availability and to
    control in coming and out going traffic.

3.2 Multiple Home Agents

    Multiple Home Agents should be geographically distributed across the
    Internet, for the improvement of service availability and for the
    load balancing of HA. When all the networks that have HA advertise
    the same network prefix to their adjacent router/network, the traffic
    is automatically routed to the nearest Home Agent from the view point
    of routing protocol topology. This operation has been already proven
    operational technology in the area of web server application, such as
    CDN (contents Delivery Network), regarding IGP and EGP.

    In order to operate multiple HAs, all HAs must have the same
    information such as binding information. This is the synchronization
    of database among the HA. This is the same architecture as I-BGP.
    The database is synchronized by full-mesh topology. In addition, in
    order to simplify operation of HA, the database is synchronized using
    star topology. This is analogy with I-BGP route reflector.

           HA1    HA1
            |      |
           ISP A--ISP B
               |   |
           CoA1|   |CoA2
            Mobile Router (MR)
                 |
             Multi-homed
             user network

      Fig.2 Architecture with HA redundancy

4. Security considerations

    This draft does not raise specific security issues beyond those of
    existing mobile IP and NEMO and routing protocols.