reachability issue with 3ffe:80a::/32 (PAIX IX segment)

[Francis Dupont]

 In your previous mail you wrote:

   	(*) currently our rule is as follows:
   	- prefixes that match 3ffe:0000::/17 and prefixlen = 24
   	- prefixes that match 3ffe:8000::/17 and prefixlen = 28
   	- prefixes that match 2001::/16 and prefixlen = 29 to 35

=> you should accept prefixes with shorter prefixlen (because someone
can aggregate some prefixes in these three blocks. I don't believe
this happens but this shall happen).

   	i can think of couple of solutions:
   	- an IX (say PAIX) gets an sTLA/pTLA.  the IX announces it to the world
   	  based on normal prefix length (like /28 for pTLA).  the IX will
   	  ensure connectivity between IX segments (so there will be no
   	  reachability issue).

=> this seems the good solution (IXes are good TLA candidates!)

   	- do not use global address on the IX segment.  I know some routers
   	  cannot establish BGP4+ peers using linklocal address.

=> if the peer address is used in order to detect loops (ie config errors)
then it is very reasonnable to mandate global addresses. Same for iBGP
or multi-hop eBGP...

Thanks

Francis.Dupont@enst-bretagne.fr