Re: multi-homing fixes

[smd () clock org (Sean M. Doran)]

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