We’re setting up CRS switches in one of the DCs where we peer with multiple other networks, to increase the number of Ethernet and Fibre interfaces available on our CCR1072 routers.
I’m having a problem with vlan’s, trunking and Q-in-Q and hope there’s someone that can assist with our configuration.
Scenario A:
[RouterBoard CCR1072 - ether1/vlan100(c-tag)] ↔ [ether1/vlan100(c-tag) - CRS - ether2/untagged] ↔ [untagged - peering network]
This works fine with the configuration I got from http://wiki.mikrotik.com/wiki/Manual:CRS_examples#Port_Based_VLAN
Scenario B:
[RouterBoard CCR1072 - ether1/vlan100(c-tag)/vlan5(c-tag)] ↔ [ether1/vlan100(c-tag) - CRS - ether2/vlan5(c-tag)] ↔ [vlan5(c-tag) - peering network]
This does not work using the same Port Based VLAN config from the Wiki because the vlan5(c-tag) get ignored by the CRS as the ports on the CRS have not been configured to be a member of VLAN ID 5.
I do not want to specify the VLAN ID that will be transported through the CRS as any traffic coming from the peering provider should simply get an additional c-tag when passing through the CRS to our CCR1072 and visa versa. Any peering network should be able to pass any VLAN ID through the CRS they want to, without the CRS switching the traffic between similar VLAN IDs, if used by more than one provider.
Should I rather be looking at Q-in-Q VLAN tunnelling and s-tags as described in http://wiki.mikrotik.com/wiki/Manual:CRS_examples#VLAN_Tunneling_.28Q-in-Q.29 or am I missing something small?