01-29-2009 11:57 PM - edited 03-04-2019 01:02 AM
Hi Folks,
Have a question that I hope you can help with.
Have two 6500 switches that are directly connected via a GigE Link.
Running OSPF between the switches. At layer 3 the switches
are connected via a point-to-point connection.
I am considering two configuration options
1. Connect the switches using a L2 trunk and use virtual
interfaces for the point-to-point L3 connection.
2. Make the physical interfaces on the switches L3
(NOT Switch ports).
My question is which option is fastest to detect a fault (and recover) at L3
when the circuit goes down?
What is the difference in the times for the options?
Hope you can help.
Best regards,
Phil
01-30-2009 04:55 AM
Hello Phil,
I wouldn't expect very big difference in times but one aspect to be considered is the
msfc autostate feature
interface vlan X is seen as up/up until there is at least one L2 port that is in spanning tree forwarding state for L2 Vlan X.
So interface SVI VLAN X may be kept up by the fact that L2 Vlan X is carried on some other L2 trunk.
A routed point-to-point interface goes down when the link is down for sure.
On the other side the L3 adjacency can be rebuild after STP convergence if there is an alternate L2 path.
Hope to help
Giuseppe
01-30-2009 07:10 AM
Hi Guiseppe,
Thanks for the reply. That was extremely helpful.
Much appreciated.
Phil
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