STP Problem 2

[iaglindro]

Good Day!

i am now trying to configure 2 more switches having this topology:

2 - 6509 (1 and 2)

2 - 3548 (3 and 4)

2 - 2950-24 (5 and 6)

1-->2-->3-->4-->5-->6-->3 and 1-->4

1-->2 trunk

2-->3 trunk

3-->4 gigastack (trunk)

4-->5 vlan 4

5-->6 FE trunk

3-->6 vlan 4

1-->4 trunk

native VLAN: 1

Problem: cannot ping interface vlan from laptop connected to 6.

Comments highly appreciated.

thanks.

cheers,

-ian

[9mmurphy]

Hello Ian,

It looks as though on switches 4, 5 and 6 only vlan 4 traffic would have access to the rest of your network. With the trunk between switch 5 and 6, I assume you have other vlans on both switches? Those vlans would not have access to the rest of your network, due to the link between 4 and 5 and the link between 3 and 6 only carry vlan 4.

HTH

[konigl]

Ian,

What Murph said.

6509(1)------trunk------6509(2)

|

|

[visualize vertical lines here indicating trunk connections between 6509 above, and 3548 directly below; hard to really draw vertically here]

|

|

3548(4)-----GS-trunk----3548(3)

|

|

[visualize vertical lines here indicating VLAN 4 connections between 3548 above, and 2950-24 below]

|

|

2950-24(5)---FE-trunk---2950-24(6)

|

|

[visualize vertical line here, connecting 2950-24(6) to laptop below]

|

|

laptop

Native VLAN is 1, only matters on VLAN trunk ports.

Assuming that VLAN 4 is the only VLAN on those two links between 3548s and 2950-24s, then those connections are VLAN access links, not VLAN trunk links. (Or, they could be VLAN trunks with all but VLAN 4 pruned off.) I guess you could think of them as "VLAN-4-only" trunks.

But VLAN 1 on the 2950-24s is isolated from VLAN 1 on the 6509s and 3548s. Not sure which interface VLAN you're trying to get through to, but I guess it's on or via the 6509s, they're the only devices capable of routing IP.

You either need to string a separate and parallel VLAN 1 connection next to each of those VLAN-4-only connections; or turn those VLAN 4 lines into VLAN trunks. Then it should work.

Is this the same network we were talking about in previous "STP Problem " post? Looks kinda similar in layout, but the bottom switches are different model...