What is interface St1 ?

[kaustav.gupta]

Hi,

I was checking show spanning-tree

in a Catalyst 4506 switch and found an interface type St1 .

Interface Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Gi1/0/1 Root FWD 4 128.1 P2p

St1 Desg FWD 19 128.1000 P2p

What is this interface St1 and what is it used for ?

Thanks in adv

Kas

[Collin Clark]

Can you post a 'show ip interface brief'?

[kaustav.gupta]

Hi,

Show Ip Interface brief does not list that interface.

Regs

kas

[prakashrj]

I have seen that kind of interface on 3750 stack switches.

do you have anything stacked?

[kaustav.gupta]

Hi,

I did not understand your query. Can u explain ?

Regs

Kas

[ankbhasi]

Hi Kaustav,

When you have switches in stack then you see an interface as stack1 in your spanning tree status. Like 3750 can be connected with another 3750 in stack so the interafce will be referred as stack.

But AFAIK there is no stack kind of stuff on 4500 so do you have switches like 3750 in stack connected to 4500 switch?

Regards,

Ankur

[kaustav.gupta]

3750 stacks are connected to the network but no directly with the 4506 switch

[kaustav.gupta]

3750 stacks are connected to the network but no directly with the 4506 switch

[kaustav.gupta]

Hi,

Let me correct myself the interface is appearing in the Catalyst 3750 switch stack. What is this interface used for ?

Regs

Kas

[ankbhasi · Accepted solution]

Hi Kaustav,

Thats right now. The interface is a stacked interface and on 3750 in STP switch stack appears as a single spanning-tree node to the rest of the network, and all stack members use the same bridge ID for a given spanning tree. The bridge ID is derived from the MAC address of the stack master.

HTH

Ankur

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