Alex Bligh <alex@alex.org.uk> writes: | The trouble with using 1 bit to represent 1 prefix is that there is | a need to move more than 1 bit of information per route between | AS's (think AS paths for loop detection, communities etc.). The bit in question when set means "a subnet which has attributes identical to the parent prefix, with the exception of the bitmap attribute colouring that parent prefix". In other words, x.x.x.x/19 [level 24, 111100001010] [other attributes] means x.x.0.0/24 [other attributes] x.x.1.0/24 [other attributes] x.x.2.0/24 [other attributes] x.x.3.x/24 [other attributes] x.x.8.x/24 [other attributes] x.x.9.x/24 [other attributes] x.x.11.x/24[other attributes] x.x.13.x/24[other attributes] plus do not install x.x.x.x/19 See what I mean by it being a compression system for more specifics? Sean. P.S.: thank you for making the iBGP and mpBGP points so clearly, too
--On Friday, August 31, 2001 8:11 AM -0700 "Sean M. Doran" <smd@clock.org> wrote:
See what I mean by it being a compression system for more specifics?
Sure, if the supernet & more specifics update atomically, you get a processing gain as well as a space / b/w gain, as you process a set of identical NLRI's in one shot (and heh, processing a route flap of ^701$ in one shot, can't be a bad thing, and a sh ip b pat or equivalent will demonstrate most routers carry tables of unique attribute sets anyway). However, I had rather assumed the point of these so-called TE more-specifics (where there are some) is that they don't all update atomically. Then you need code to split them out and put them back together again, and though you are doing better on bandwidth for the updates (which is not a problem anyway) you are doing worse on space & processor power. I may be missing something. -- Alex Bligh Personal Capacity
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