07-21-2010 04:59 AM - edited 03-06-2019 12:07 PM
Hi All
I have 10 cisco Switch 3750 in LAN. All these are in connected in Ring. All those are configured with multiple VLAN's and Routing is also enable. I want to enable STP on all these switches. In case if any links drop between two switches and auto backup from other side.
I would apperciate if anyone can help.
Thanx
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07-21-2010 05:12 AM
STP is enable by defualt
you can chek it by using the command : show spanning-tree vlan 1
the defualt span mode is : PVST+ (peer vlan spanning-tree)
07-21-2010 05:12 AM
STP is enable by defualt
you can chek it by using the command : show spanning-tree vlan 1
the defualt span mode is : PVST+ (peer vlan spanning-tree)
07-21-2010 05:45 AM
Thanx for reply,
yeah this is right, By default this is enable on cisco Swiches 3750.
I want to make one switch as a Root Switch and others as client.
so does i need to configure only my Root Switch for STP or i will enable on all switches.
07-21-2010 06:05 AM
By default STP will choose one switch as root bridge.
Any switch you want elected as root bridge for all vlan do the below configuration on it
sw 1 (config) #spanning-tree vlan (vlans id e.x:1,3-5) root primary
if you if this switch go down and you don’t want STP calculate and choose any switch
you can go to second switch and use :
sw 1 (config) #spanning-tree vlan (vlans id e.x:1,3-5) root secondary
07-21-2010 06:32 AM
It mean i need just configure only root Switch and did disable STP on other switches ?
07-21-2010 06:43 AM
No ,
STP :
why using STP : to prevent L2 loop
How : by find one single path between two switches.
,,,,,,,,,,,,,,,,,,,,,
in STP domain must one switch come root bridge.
so you don’t need disable in other switches
My recommendation keep the STP as is . And read about STP protocol
07-27-2010 02:50 AM
Please note that STP is limited to 7 successives links.
So in your case (10 swoiches in ring), I am afraid the topology could
not be computed in case of failure of one link.
07-27-2010 03:41 AM
I Agree with that. It is known that STP start making issues once the ring goes beyond 6 or 7 switches.
If your Vlans are all local to one switch (ex. sw 1 has vlan 20,30. sw 2 has vlan 40,50). then i would recommend to change the connecting links to routed ports and just do proper routing between. the routing protocols will take care of loops/convergence in case of link failures.
07-27-2010 07:28 AM
All the core(3750) switch are connected on trunk and Distribution(3500/2950) switch are also connected on trunk with core switch(3750), then on Distribution switch (3500/2950) srw/Netgare are connected through VLAN
07-27-2010 03:00 PM
drawing could be nice. didnt understand the topology.
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