[j-nsp] Running OSPF to manage loopbacks, only have trunks
juniperdude at gmail.com
Wed Aug 31 03:12:19 EDT 2011
> Could you elaborate on:
> Just need to be careful to bridge the VLAN across the trunk link as necessary. (i.e. only bridge what you need - switch to switch - don't use 'vlan members all').
> What would be the problem if I did all? I might have say tag 2001 going to a switch that doesn't play on that vlan, but I wouldn't have problems necessarily would I?
You're right. It wouldn't necessarily be an issue.
What I'm trying to avoid is bridging VLAN 2001 everywhere (and we're back to the original '1 giant LAN' problem).
Switch 1 <> Switch 2 uses VLAN 2001
Switch 2 <> Switch 3 uses VLAN 2002
Switch 3 <> Switch 1 uses VLAN 2003
All inter-switch links declared 'family ethernet switching port-mode trunk members vlan all'.
Agreed, if switch 3 doesn't have tag 2001 declared, it'll just ignore it / not pass it back to switch 1.
However, if you're using a base RSTP topology (VLAN unaware), then one of those inter-switch links is going to block.
You will not have routing/IP connectivity on one of the inter-switch links. However, this is not necessarily a problem.... If RSTP blocks between a pair of switches, OSPF will just lose the inter-switch adjacency - but not reachability of each switch in the OSPF database (The Type 1's are all still there). The traceroute simply follows the current RSTP forwarding topology.
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