I'm trying to figure out how to create a Layer 3 q-in-q interface in Exos on a summit X440 switch.
I've opened a ticket with support but I'm not getting anywhere so if anyone in the community can help I'd appreciate it.
If I need special licensing, a newer firmware version, or even a different model switch I'm open ...but I'm looking to solve the problem with an EXOS solution. I do not want to buy more Cisco stuff. (I'm trying to get rid of the cisco stuff lol) It doesn't make me look good as a sales partner with Extreme to run a bunch of multi-vendor Cisco stuff to achieve our networking goals.
I need to create a logical interface on the switch within the CVID of a VMAN for inter-vlan routing of CVID's, in other words, double-tagged logical interfaces with L3 forwarding enabled.
From Extreme, there is just the S-Series able to provide layer 3 forwarding in a VXLAN, but even those switches do not provide layer 3 VXLAN interfaces, just VLAN interfaces.
Q-in-Q provides much better hardware support and less overhead (4 bytes instead of 50) than VXLAN. Software implementations (e.g. Cisco routers or a GNU/Linux host) provide practically unlimited scalability for layer 3 interfaces using stacked VLANs (interfaces matching on both S-Tag and C-Tag).
as far as I know the IOS stacked VLAN routing example you gave works with Cisco routers only, not with switches. Switches usually support Q-in-Q only as a layer 2 mechanism (I have checked this for EXOS, (Extreme) EOS, Cisco IOS, and Arista EOS recently).
You might be able to use two EXOS devices, one to de-encapsulate Q-in-Q and another to implement routing, using VRs to separate layer 3 networks. But that does not scale, as you would need one cable (untagged port) per routing interface in general (i.e. with overlapping customer VLAN IDs).
Port specific VLAN IDs might help to get around the 1 port per layer 3 interface problem, but those cannot be combined with a layer 3 interface in the translated VLAN on the same switch, thus you still need at least two devices (I did not check the possibility of combining Q-in-Q and VLAN translation).