QinQ vlans on PE

[carl_townshend]

Hi Guys

Our ISP uses QinQ on there customer facing interface on the PE, we use vlan 4000 on our CE router.

My question is, what happens at the PE when they receive the tagged packets with us, I can see they have an outer vlan of 2993 and inner of 4000.

Would the last mile provider i.e transmission network have do understand these vlans on the mux etc?

What vlan does the IP address apply to?

Would the PE basically use the outer vlan 2993 to switch it through there network or something else?

config on PE below

Internet address is 10.20.1.125/30
MTU 9058 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation QinQ Virtual LAN, outer ID 2993, inner ID 4000

[MHM Cisco World]

Lessons Learned: Cisco Catalyst Q-in-Q – David Vassallo's Blog

check this link.

[carl_townshend]

Hi

Thanks for the link, its not what I am looking for though, we use q in q "tunneling" on our switches already, my question was more how its being used on the router in the config shown above, I also want to know which vlan the ip address would apply to on the interface, would it be the outer or inner etc?

[MHM Cisco World]

encapsulation dot1q <OUTER> second-dot1q <INNER>

if you talk about the command and how it work please see above  

[rais]

VLAN 4000 tag is part of payload for the ISP. They only need be concerned with the outer label to route the payload properly.

[carl_townshend]

Hi, so when the packet arrives at the PE, which vlan tag will correspond to the IP address of the interface?

From my perspective, on our CE the other end of the IP is the PE on a /30 and we use vlan 4000, so does the IP of the PE's vlan interface use the ip on vlan 4000 (inner vlan)

[MHM Cisco World]

Sorry you are CE side or PE side 

If you  PE command above 

If you are CE side then no need any QinQ' QinQ is config only in PE.

In CE config subinterface with vlan 4000.

[carl_townshend]

Hi, yes I am CE, still I am looking for response on which vlan the ip address on the PE interface will map to?

[MHM Cisco World]

Config CE with vlan 4000.

[carl_townshend]

hi

can you tell me what happens at PE when it sees the CE traffic tagged with vlan 4000?

what does it do with the outer label ?

does that mean there is equipment between the PE and CE using the outer tag ?

Also, the ip address on the PE interface facing the CE, what vlan does it map to ? The outer or inter vlan ?

[MHM Cisco World]

 I can see they have an outer vlan of 2993 and inner of 4000. <<- I mention before you must use 4000 in CE , as you write in first post this inner not outer.
am I right ?

CE-Inner VLAN-PE-outer VLAN-PE-Inner VLAN- CE 

the outer VLAN is use to connect between PE's
inner VLAN connect CE to PE 

[rais]

QinQ is usually switched [not routed] across an ISP network using S-VLAN [outer/service provider vlan]. Once the packet exits the network S-VLAN can be removed and C-VLAN [customer vlan] exposed to the customer.