From: Mohammad Saeed (mzsaeed@gmail.com)
Date: Mon Nov 12 2007 - 16:27:20 ART
Hello,
We have three switches say SW1, SW2 and SW3 from top to bottom. SW1 on
the top has lowest priority 8192 and its the ROOT for vlan 1. Now SW2
and 3 have same priority 32769 but SW3 has lower value MAC Address, so
if SW1 goes down, SW3 shall be root, but link between SW2 and 3 goes
down when SW1 goes down and everything beyond SW3 including SW3
becomes unreachable from SW2 unless we bounce the interface on SW2
connecting to SW3 and then we can access SW3 and Switches attached to
SW3..... Can any one see/point out where problem can be?
g5/39 interface on SW2 (connecting to SW3 's g0/1) have no config
under it, so it shall be working with default auto speed and auto
duplex and when SW1 is available its designated port but when SW1 goes
down and root switch election occurs, it shall be Root Port as SW3
shall be elected as root as SW3 has lower mac address (SW2 and SW3
have same priority 32769 for vlan 1) but this port goes down....
g0/1 interface on SW3 (connecting to g5/39 on SW2) have channel-group
3 mode desirable command only under interface, although int po3 is
always down because of other config issue, so if SW1 is up and root,
this link stays up, but if SW1 goes down, we can not access SW3 as its
only access path is through SW2 and its interface connecting to SW3
stays down/down....
The only thing that I suspect may cause problem is that g0/2 on SW3,
its description shows thats its connecting to SW1 and its part of
port-channel 3 ( I think thats why int po3 is down as one cable in
port channel going to one switch and second cable to other switch) and
also sh int g0/2 shows down/down state...
Also, if we put spanning-tree vlan 1 root secondary on multiple
switches, would this command different priority on all switches having
this command or they will have same and if switch having spanning-tree
vlan 1 root primary goes down, they will again be doing re-election or
this macro will assign different values to all having spanning-tree
vlan 1 root secondary command?????
Thanks in advance for help...
Regards,
Mohammad Zahed Saeed
This archive was generated by hypermail 2.1.4 : Sat Dec 01 2007 - 06:37:29 ART