[rbridge] IS-IS pseudonodes, nicknames, and rooted trees
Radia.Perlman at sun.com
Sun Jan 7 17:01:19 PST 2007
In IS-IS, a shared link is treated as a "pseudonode" -- as if it were
another router. The purpose of
this is because the routing algorithm scales as the number of links, so
a link with n router neighbors
becomes n+1 nodes with n links rather than fully connected, order of n^2
The Designated Router gives the pseudonode a name (in IS-IS, a 7-byte ID
a 6-byte EUI owned by the DR, plus an extra byte to differentiate among
links that that router
is DR for), and generates an LSP on behalf of the pseudonode.
Anyway, the question is -- should we allow/require pseudonodes to be
assigned RBridge nicknames?
There are two reasons for obtaining an RBridge nickname
1) to be specified as the egress RBridge of a data packet -- I don't
think this will ever be relevant
2) to be specified as the root of a tree
My inclination is to say pseudonodes cannot be egress RBridges, or
specified as tree roots, and
therefore pseudonodes will not be given nicknames.
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