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Radia Perlman Radia.Perlman@sun.com. TRILL issue: Scaling of pseudonodes. DR election per VLAN.
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Radia Perlman Radia.Perlman@sun.com TRILL issue: Scaling of pseudonodes
DR election per VLAN • Unfortunately, because of possible bridge configuration, it is possible to have a layer 2 cloud partitioned with respect to VLAN A, but not with respect to VLAN B. So you'd need two DRBs for VLAN A, and one for VLAN B • To really know if you can talk to R1 on a cloud with VLAN A, you need to tag a Hello with that
But you don't want to have 4000 pseudonodes • So...it works to have one pseudonode for each DRB/port • If R1 is DRB for VLANs {A, B, D, H}, then create a single pseudonode • In IS-IS Hellos, same name regardless of VLAN • So...possible for R1 and R2 not to be able to talk even though they're on the same VLAN
If R2 can't talk to R3 • Link state database says next hop is pseudonode, and next hop is R3 • But R2 can't talk to R3 • Already in IS-IS: in that case, send to DR • This was put in because of bizarre error cases of nontransitive connectivity • Which bridges give us the opportunity to cause