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reachability issue with 3ffe:80a::/32 (PAIX IX segment)
- Subject: reachability issue with 3ffe:80a::/32 (PAIX IX segment)
- From: [email protected] (Jun-ichiro itojun Hagino)
- Date: Wed, 17 Jan 2001 21:13:59 +0900
# not sure why it did not get through.
at PAIX, we use 3ffe:80a::/32 (acutally 3ffe:80a::/64) for the
peering segment between ISPs. 3ffe:800::/24 is assigned to ISI,
and as ISI and PAIX are not directly connected, 3ffe:800::/24 has
two (or more) disconnected networks.
we did not expect to receive/propagate prefixes longer than
sTLA/pTLA prefixes (*), our EBGP routers filter out logner prefixes
(as suggested in 6bone operation RFC) and internal routers do not have
the route for 3ffe:80a::/32. packets to 3ffe:80a::/32 get routed to
ISI (instead of PAIX) and get dropped.
(*) 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
- prefixes that match 2000::/3 and prefixlen = 16
- prefixes specifically agreed with other peers
what should we do? if we need to receive/propagate 3ffe:80a::/32 or
/64, we may just need to do that and then the particular problem will
be solved. however, i have some worry here... if we add more and more
practice like this, we eventually get more external routes.
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
- define an address range for IX segments (like 3ffe:fff0::/28).
assign /48 out of it to IX (who assigns it is another question).
ask everyone to accept /48 (not just /28) for the prefix.
- do not use global address on the IX segment. I know some routers
cannot establish BGP4+ peers using linklocal address.
- get 1 sTLA/pTLA prefix for each of the IX segment. it is infeasible.
what do people think?