Using an ASR9000 with Calix E7 gear

I worked recently to add a Calix E7 to a network to do GPON Fiber for Ethernet customers. The customers would need to get a dhcp address for a dhcp server, and I needed to add DHCP Option 82 logging for record keeping purposes. I needed the E7 to terminate an 802.1q trunk into the ASR to allow the management and customers to live in different networks. Setting up the Port to terminate two different BVI’s was fairly straightforward. I would up with something like the following configuration.

!
interface GigabitEthernet0/1/0/1
description Calix E7
!
interface GigabitEthernet0/1/0/1.100 l2transport
encapsulation dot1q 100
rewrite ingress tag pop 1 symmetric
!
interface GigabitEthernet0/1/0/1.200 l2transport
encapsulation dot1q 200
rewrite ingress tag pop 1 symmetric
!
!
interface BVI100
description New Equipment Network
ipv4 address 192.0.2.65 255.255.255.192
!
interface BVI200
description Calix
ipv4 address 192.0.2.193 255.255.255.192
!
l2vpn
bridge group Calix
bridge-domain Calix Customers
interface GigabitEthernet0/1/0/1.100
!
routed interface BVI100
!
!
bridge group Equipment
bridge-domain Equipment Network
interface GigabitEthernet0/1/0/0.200
!
interface GigabitEthernet0/1/0/1.200
!
routed interface BVI200
!
!
!


Next I tried to set up a dhcp relay for the Calix BVI


interface BVI200
description Calix
ipv4 helper-address vrf default 192.0.2.5
ipv4 address 192.0.2.193 255.255.255.192
!


However this configuration was not relaying DHCP request to the server. After reading some of the IOS-XR documentation, I found out that I needed to set up a DHCP profile to relay DHCP. I added the following lines.

!
dhcp ipv4
profile Calix relay
giaddr policy replace
helper-address vrf default 216.172.112.5
relay information policy keep
!
interface BVI200 relay profile Calix
!


While I was getting DHCP to relay, I could only do it when I had Option82 disabled on the Calix. After further research I found I needed to add relay information option allow-untrusted to the profile to get dhcp to forward a broadcast that has an option82 tag added to the dhcp request. My final configuration was the following.

!! IOS XR Configuration 4.2.0
dhcp ipv4
profile Calix relay
giaddr policy replace
helper-address vrf default 216.172.112.5
relay information policy keep
relay information option allow-untrusted
!
interface BVI200 relay profile Calix
!
interface GigabitEthernet0/1/0/1
description Calix E7
!
interface GigabitEthernet0/1/0/1.100 l2transport
encapsulation dot1q 100
rewrite ingress tag pop 1 symmetric
!
interface GigabitEthernet0/1/0/1.200 l2transport
encapsulation dot1q 200
rewrite ingress tag pop 1 symmetric
!
interface BVI100
description New Equipment Network
ipv4 address 192.0.2.65 255.255.255.192
!
interface BVI200
description Calix
ipv4 address 192.0.2.193 255.255.255.192
!
l2vpn
bridge group Calix
bridge-domain Calix-Customers
interface GigabitEthernet0/1/0/1.100
!
routed interface BVI100
!
!
bridge group Equipment
bridge-domain Equipment-Network
interface GigabitEthernet0/1/0/0.200
!
interface GigabitEthernet0/1/0/1.200
!
routed interface BVI200
!
!
!
end