01-10-2012 05:33 PM - edited 03-07-2019 04:16 AM
Hi there,
At a college I'm trying to setup a Cisco 2960 to be used on a VLAN 248 tagged on the uplink port that uses Spanning Tree/
Here is the following from the Cisco:
show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gi0/1 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi0/1 248
Port Vlans allowed and active in management domain
Gi0/1 248
Port Vlans in spanning tree forwarding state and not pruned
Gi0/1 248
All the FastEthernet ports are the same:
interface FastEthernet0/24
switchport access vlan 248
switchport mode access
!
This is the uplink port:
interface GigabitEthernet0/1
switchport trunk allowed vlan 248
switchport mode trunk
switchport nonegotiate
!
On the Alcatel OS6850-48L the following is setup:
bridge 1x1 248 priority 3287
Vlan 248 802.1q 5/8 "cisco"
I cannot make a change on the Alcatel, I can only adminsiter the Cisco. I was able to get things working fine (as a test) using a Netgear or HP switch instead of the Cisco. However we have a Cisco switches and would not like to have to buy HPs.
Is there a compatible spanning tree protocol to use on the Cisco with the way things are configured on the Alcatel.
I need to stick to standard RSTP (802.1w) ieee standards and not something Cisco proprietary.
Thank you,
Lawrence
01-10-2012 05:52 PM
Hi,
Can you add "switchport trunk encapsulation dot1q" to interface Gi0/1 and test again?
HTH
01-10-2012 06:01 PM
Thanks for the quick reply!
That option is unavailable on the switch it seems:
switchport trunk ?
allowed Set allowed VLAN characteristics when interface is in trunking mode
native Set trunking native characteristics when interface is in trunking mode
pruning Set pruning VLAN characteristics when interface is in trunking mode
However it does show that it is doing 802.1q:
show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gi0/1 on 802.1q trunking 1
Is the what "switchport trunk encapsulation dot1q" does?
Lawrence
01-10-2012 06:18 PM
Is the what "switchport trunk encapsulation dot1q" does?
Yes, however if I would look closer, I should have seen it in your first post. So, you are already good with .1Q.
Is vlan 248 in up and up mode?
"sh ip int bri vlan 248" will show you that
HTH
01-10-2012 06:40 PM
I think the question is about Spanning-Tree, not VLAN tagging, as the two switches both appear to be using the same encapsulation mode (they must be, as neither of them supports any other).
The OP seems to be implying that he is using 802.1w on the Alcatel. He would need to check to be sure, as Alcatel would also support and could be configured for 802.1d or 802.1s.
Try "spanning-tree mode mst" on the Cisco switch. By default it will be pvst+, which the Alcatel would not like.
Alternatively, can you get LACP working between the two?
01-11-2012 02:15 PM
I spoke with Cisco today and they said to use: spanning-tree mode rapid-pvst
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