>From my point of view, it would be nice to have shorter massages, because I am >using protocol on very limited bandwidth link, also is better to have shorter >messages anyway. But that is only my opinion.
Robert -----Original Message----- From: [EMAIL PROTECTED] on behalf of Juliusz Chroboczek Sent: Mon 7/7/2008 9:12 PM To: [email protected] Subject: [Babel-users] Loose ends with Babel There are a few things that keep nagging me about the current protocol spec and implementation, and that I may decide to fix at some point. This is more of a note to self then a public discussion, but don't hesitate to chime in if you have any comments. 1. The IHU definition is broken Babel identifies routers with router ids, and interfaces with link-local addresses. Link quality is a property of a pair of interfaces, not a pair of routers. The IHU message should be carrying an interface id (a link-local address) rather than a router-id. This is the fundamental reason for the previous issue reported by Robert (the one with multiple link-local addresses). (I'm not so sure about HELLO messages; keeping the router id in them might be a good idea, in order to simplify debugging.) Fixing that will require an incompatible protocol revision. It's definitely a good idea. 2. The handling of idle interfaces is idiosyncratic Idle interfaces (see -i in the manual page) are handled in an idiosyncratic manner, by a bunch of ifs sprinkled throughout the code. It'd be nice to clean up this mess. 3. The handling of down interfaces is idiosyncratic The handling of down interfaces (interfaces that are currently down, or, if -l was specified, that report no link sense) are handled idiosyncratically, by a bunch of ifs throughout the code. I'm not sure this can be fixed, cross-layer indications are notoriously tricky to do in a modular way. 4. The protocol is bloated The protocol currently uses fixed-length 24-byte messages, large enough to contain an IPv6 address. This means its sweet and simple, but makes some messages somewhat larger than they could be. Switching to variable-length messages (smaller for IPv4 than for IPv6) will reduce the size of update messages by 2/3 for pure IPv4 networks, and by 1/3 on mixed-stack networks. I've done a pretty good job of reducing unnecessary update traffic, so I'm not sure that it's really worth the trouble. This, again, will require an incompatible change, and I'm not sure it's a good idea. Juliusz _______________________________________________ Babel-users mailing list [email protected] http://lists.alioth.debian.org/mailman/listinfo/babel-users
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