IPv6 addresses for EP or why are exhanges so special ?
Randy Bush randy at psg.com
Thu May 17 02:19:09 CEST 2001
>> * why are exchange points so special? > My take on this is that "they are not". i suggest that they are. they want just a subnet or site of address space but have no upstream provider(s) from which to get it. hence they want to go to the rir. > For the exchange point medium itself, if the medium is a "multiple- > access broadcast network" it *is* actually a benefit to use the > "natural" way to number such networks, i.e. use a single IP subnet, > as in that case you can use BGP in the "standard configuration". bgp is not needed at all, as the exchange point has no asn, and the prefix is internal to the attached providers. > If your exchange point is implemented using a "multiple-access > non-broadcast network" of some sort, the multiple point-to- point > links, each with their own subnet out of a connected peer's address > block makes sense. yup. you should be able number it as multiple private peerings. but it might be a bit of an adminsitrative pain to an exchange with an mpla as opposed to bi-lats. uncommon case. > Some have said that the IP network used to number the exchange > itself does not have to be announced on the global level. However, > it would appear that practices vary quite widely on this point for > IPv4, and many are announced globally. but they need not be and a bunch of folk asked/agreed not to. and it goes against the 1930 in that the same prefix is originating from more than one asn. this is not deadly, but not pretty, and ill-advised, when there is no need. > You mention the possible use of link-local addresses as you hint, not nice to traceroute through the exchange. > As for the "service network", it will of course need global > connectivity, and thus has to get transit service from one or more > ISPs. What I don't understand is why this service network needs to > be so special up and above other normal customers when it comes to IP > address assignment? i agree that it does not. randy
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