[BNG] IPadd in unnumbered loopback has to match the giaddr proxy conf

[Carlos A. Silva]

Hi,

When testing BNG IPv4 IPoE session I noticed that if the IPv4 address of the loopback you configure in the unnumbered setup for BNG does not match the giaddr configured in the dhcp ipv4 proxy statements, the IPoE session won't complete.

I tried these scenarios (won't share the actual public IPs):

Loopback: 10.0.0.1/32 +  giaddr: 10.0.0.1 , dhcp pool: 10.0.0.0/27 ---> works, IP session completes

Loopback: 10.0.0.2/32 +  giaddr: 10.0.0.2 , dhcp pool: 10.0.0.0/27 ---> works, IP session completes

Loopback: 10.0.0.1/32 +  giaddr: 10.0.0.2 , dhcp pool: 10.0.0.0/27 ---> doesn't work , IP session does not complete

Loopback: 10.0.0.2/32 +  giaddr: 10.0.0.1, dhcp pool: 10.0.0.0/27 ---> doesn't work , IP session does not complete

Can somebody explain why, please? Does this have anything to do with internal processing of the IP sessions in Cisco XR?

Thanks in advance!

c.

[Giuseppe Larosa]

Hello @Carlos A. Silva ,

yes  what you see is expected  the  loopback address  is used   for virtual  template with    ip unnumbered loopback X .

the virtual template is used to create virtual access child nterfaces that are  the  sessions.

This  framework  has  been created for PPPoA,PPPoEoA,PPPoE   scenarios where  PPP  and Radius  are involved.

For IP over ethernet sessions  only   DHCP  is  involved  so  it makes  sense  what you see.

Hope to help

Giuseppe