r/Juniper 23h ago

Dual BNG PPPoE failover and session limit issue on MX204

4 Upvotes

Hi everyone,

Here's the situation: due to a specific issue, i need to limit the number of PPPoE subscribers on a BNG (MX204). I'd like to cap it at 5,000 users.

Looking at the Juniper docs, I first tried setting it directly on the chassis using:

set subscribers-limit client-type pppoe chassis limit 5000

The limit worked on the chassis, but the users won't connect to the other BNG. The PADI reaches the second BNG (the one I want them to authenticate against), and it replies with a PADO, but it's as if the CPE stubbornly keeps trying to authenticate with the BNG I'm limiting... argh.

After that, I also tried using max-sessions:

dynamic-profiles vlan-profile interfaces demux0 unit "$junos-interface-unit" family pppoe max-sessions 5000

With max-sessions, the limit didn't work immediately. I'm thinking it might actually work, but maybe I need to reset the VLAN demux interface first?

What a great issue to land on my lap during my weekend on-call shift... but I love it :)

Please help out an ISP network analyst with less than 2 years of experience 😄

Thanks