Babel Distance-vector routing protocol for IPv6 and IPv4 with fast convergence properties
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protocol compute route rounting protocol compute route metric inject external route

Babel Description

Distance-vector routing protocol for IPv6 and IPv4 with fast convergence properties Babel is a distance vector protocol that is designed to be robust both on classical wired networks and on wireless mesh networks. Babel operation is similar to that of familiar distance-vector routing protocols, such as RIP and RIPng.It is based on the ideas in DSDV, AODV and Cisco's EIGRP, but uses a variant of ETX link cost estimation rather than a simple hop-count metric. Babel was designed to be robust and efficient on both wireless mesh networks and classical wired networks.In its default operation, Babel uses a link quality measurement that is designed for networks using the IEEE 802.11 MAC. In other words, the paths chosen should be reasonable on any sort of network, but are particularly suitable for 802.11 networks.Babel uses a number of techniques to avoid route flapping, the situation in which routers repeatedly switch between two routes of similar quality. This, again, is unlike OLSR, which, being a link-state protocol, cannot reliably implement history-dependent route selection.Babel will also work efficiently on wired networks. When operating over a wired network, it will use a larger interval between hellos, perform split-horizon processing and disable link quality estimation. Here are some key features of "Babel": · It is a distance-vector protocol; · It is a proactive protocol, but with adaptative (reactive) features; · It senses link quality for computing route metrics using a variant of the ETX algorithm; · It uses a feasibility condition that guarantees the absence of loops (the feasibility condition is taken from EIGRP and is somewhat less strict than the one in AODV); · It uses sequence numbers to make old routes feasible again (like DSDV and AODV, but unlike EIGRP); · It allows redistributed external routes to be injected into the routing domain at multiple points (like EIGRP, but unlike DSDV and AODV). What's New in This Release: · Fixed a bug that broke link-quality estimation, and could cause severe instability when we had both good and marginal neighbours. · We now send retractions after a redistributed route is retracted. · Fixed a bug that could cause reliable messages (retractions and router-id switches) to only be sent twice. · We no longer obey a silent time at startup, instead sending a bunch of retractions. The silent time is inconvenient, but seldom useful. · Updates for routes to self are now sent together with other updates (they used to be sent more frequently). · Fixes the configuration parser to interpret hello-interval as a number of seconds, as specified in the documentation (it used to be interpreted as a number of milliseconds). · INCOMPATIBLE CHANGE: the update interval is now a per-interface value, may be configured manually in the configuraton file, and defaults to 4 times the hello interval. The -u flag is gone.

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