06-22-2019 01:03 PM - edited 06-22-2019 01:12 PM
Hello all! I have a Cisco 3800 series MLS, on this switch I have a transient VLAN(Vlan 400) that connects to a unrelated customer network.
Attached to the 3800 on my side of the network I have multiple switches using VLANs 100, 200 and 300.
The traffic from VLANs 100, 200 and 300 are routed over the transient VLAN(400) where they are processed and returned via the same route.
My question is, do I need to specify VLAN 400, the transient VLAN on all my switches and trunks that are behind the customer network for the traffic to successfully go from VLAN 100, 200 and 300 across the transient VLAN(400) and then return to VLANs 100,200,300?
If so, why?
Solved! Go to Solution.
06-22-2019 03:34 PM
No, vlan 400 most likely is configured as untagged (access port). Is just like a layer-3 point-to-point link with IP an each side. In this case it is vlan with SVI and IP configured on each side of the connection.
HTH
06-22-2019 01:30 PM - edited 06-22-2019 01:31 PM
Hi,
No, the transit vlan 400 is just a layer-3 boundary between your switch and the customer (2 devices) and does not need to be define anywhere else.
HTH
06-22-2019 01:48 PM
So, help me understand why. Is the VLAN 400 traffic not tagged from the customer side?
06-22-2019 03:34 PM
No, vlan 400 most likely is configured as untagged (access port). Is just like a layer-3 point-to-point link with IP an each side. In this case it is vlan with SVI and IP configured on each side of the connection.
HTH
06-22-2019 04:00 PM - edited 06-22-2019 04:02 PM
So, do I even need the VLAN 400 for the transient ports? I guess I'm not understanding why these ports would need to be configured this way. Why not just create layer 3 ports with an IP address?
Thanks for the explanation.
06-23-2019 09:36 AM
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