Brian E Carpenter wrote:
By changes of mode, presumably you mean multi-homed -> single-homed -> multi-homed?Another point is that a normal scenario for a dual homed site wishing to change one of its ISPs would be to triple-home for a while (i.e. add ISP C while retaining ISPs A and B) and then drop A or B once things are stable with C. So changing from 2 to 3 and then back to 2 should be a simple operation, not two changes of mode.
I don't think that would be strictly necessary. Each EID prefix is constructed based on a pair of upstreams.However, there could be multiple EID prefixes, announced with different preferences on them.
They would be ABab, ACac, and BCbc. Sort them however you want, change them as C gets ironed out.
And eventually disconnect A or B, and magically the EIDs with A or B in them go away.
Obviously, in this scheme, removing an uplink could break existing connections, but I doubt that's a show-stopper.
Brian Dickson -- to unsubscribe send a message to rrg-request@psg.com with the word 'unsubscribe' in a single line as the message text body. archive: <http://psg.com/lists/rrg/> & ftp://psg.com/pub/lists/rrg