NEMO Basic Support, Multi-homing and Service Discovery
The IPv6 mobility is mainly managed by two protocols defined at the IETF : Mobile IPv6 and NEMO BS (NEtwork MObility Basic Support). Mobile IPv6 enables single host mobility across different IPv6 networks whereas NEMO BS manages the mobility of an entire IPv6 network (known as mobile network). With NEMO BS, all the mobility management complexity is centralized on a dedicated node: the mobile router. By this means, every movement (when the mobile network roams from one access network to another) is completely hidden to the nodes located in the mobile network. As a result, a legacy IPv6 node (when connected to a mobile network) can benefit from pervasive IPv6 connectivity without the needs of additional software or great configuration skills. Coupled with specific extensions, NEMO BS can also take benefit from multi-interfaced devices to enable multihoming support in the mobile network.
- Bootstrapping autoconfiguration
- Mobile routers autoconfiguration at start-up
- Service discovery over the mobile network
- Load sharing and balancing
- Fault tolerance
- Auto-adaptive user softwares
- Multiple mobile routers management
To illustrate the mechanisms introduced by NEMO BS, we have set up a scenario in which an ISP provides an IPv6 mobility service through NEMO BS support. When the mobile network roams between various access networks, the NEMO BS protocol maintains the continuity of user sessions and flows. Thanks to the NEMO BS mechanisms, such movement remains imperceptible for users.
The showcase platform introduces the following entities:
- The mobility service
- The home agent
- The mobile router
- The IPv6 media servers (the service gateways)
- The users of the mobile IPv6 network (the clients)
At the boot sequence, the mobile router automatically retrieves its network and NEMO BS configurations from the ISP. Then, the users can join the mobile network and benefit from IPv6 Internet. In addition, they can automatically discover the IPv6 services provided by the operator. Finally, the mobile network moves to a new access network while users continue their ongoing communications.
The following video explains the various protocols used in such scenario, followed by a demonstration of our mobility test platform. This video can be retrieved with a better quality from this URL (Quicktime movie, 13Mo).
The above video details the following topics:
The mobile router operates the NEMO BS protocol that allows it to be always reachable through its primary IPv6 address, as well as all the nodes in the mobile network. This primary address is associated with a temporary one and both are registered on a home agent. This temporary address represents the real location of the mobile router in the Internet topology, and is updated each time the mobile router moves to a new access network.
All the flows destined to the mobile network are always passing through the home agent, which can thus ensure session continuity while the mobile network is moving.
the mobile router has multiple network interfaces to connect to various access networks at the same time. Its primary IPv6 address is then associated to multiple temporary IPv6 addresses (one per interface) thanks to the Multiple Care-of Addresses registration (MCoA) protocol. Multiple concurrent paths can thus be maintained between the mobile router and its home agent.
Flows from the Internet to the mobile network and conversely are routed respectively by the home agent or the mobile router according to their preferences or routing policies.
Multiple flows can thus be shared among the multiple concurrent paths according to the protocol or port number. The mobile router and the home agent can also easily face a breakdown or a disconnexion from an access network by redirecting the flows to another available path.
We are also working on the management of multiple mobile routers located in the same mobile network. We are particularly interested in the redundancy of the mobile routers while extending the load sharing and fault tolerance solutions in this context.
At the operator level, the mobile router is autoconfigured with the correct parameters (prefix of the mobile network, address of the home agent, etc.).
In the mobile network, the network parameters of associated clients are automatically configured through standard IPv6 mechanisms. In addition, the clients automatically discover the available services (including the parameters to access to these services) such as VoD or VoIP services. Therefore, no configuration is required from the end-user.