10-30-2007 07:43 AM - edited 03-03-2019 05:33 AM
I have a 100Mb leased line with a 2621 router at each end. I want to span vlan's across this line and have created subinterfaces on the fa0/0 interface on each as follows:
interface FastEthernet0/0
no ip address
speed 100
full-duplex
!
interface FastEthernet0/0.50
encapsulation dot1Q 50
ip address 10.1.50.28 255.255.255.224
!
interface FastEthernet0/0.254
encapsulation dot1Q 254 native
ip address 10.0.254.25 255.255.255.248
!
interface FastEthernet0/1
ip address 10.1.254.1 255.255.255.0
speed 100
full-duplex
!
The config is the same at both side, but with a different IP address in the same subnet range.
I can now ping between the ip addresses associated with the subinterfaces on the native vlan, but I cannot ping between those non-native vlans.
Any ideas?
Thanks in advance.
Campbell
10-30-2007 02:12 PM
Hi,
you need to ask your metro SP to carry 802.1q. They need to support what is called "Q-in-Q".
Hope this helps, please rate post if it does!
10-31-2007 03:25 AM
I got excited about that, but alas no, I spoke to the SP and it's fibre with little in the way of hardware in between.
I'm at a loss...
10-31-2007 04:58 AM
Do they only have media converters to present you the circuit over copper? Positive not even a switch in between ?
Easy check to confirm switch presence is that if you unplug one side the other stays up.
10-31-2007 05:12 AM
Yes, just media converters.
Is there anyway I can debug at packet level to make sure the reference is the same at both sides?
10-31-2007 07:02 AM
Campbell,
this is supposed to work as configured. You can attached a to PC with analyzer to confirm the router is sending the correct encap. Note you need a NIC driver with support for 802.1q to see tagged frames on the PC (not all NICs are like that).
10-31-2007 07:05 AM
Okay, managed to get it working, but I needed to change the encapsulation on the outside port on each router from dot1q to isl... Very weird...
Any thoughts on why this would work?
Campbell
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