Question

ELRP on protocol IP


Hello,
Im looking for sollution for loop protection on xos, and i found ELRP. But it doesnt work on vlan configured as protocol ip, as i have on my company.

I found two solutions, but im not sure is the first one safe?

1. Adding snap 0x00bb to protocol ip. Does any one encounter any difficulties with that?

configure protocol ip add snap 0x00bb

2. Create second vlan configured with any protocol, and add it as tagged on every access port, and turn on elrp on this vlan. Its easier to implement, but IMO its harder to management. I would like to stick with first soluttion.

Or maybe there is third solution?

Regards,
Michael


4 replies

We use a vlan "no_loop" tagged on all ports to run elrp. You just have to remember to exclude your uplink ports. It is a very simple implementation and works great.
Userlevel 6
ELRP is a multicast based loop protection protocol. Are you saying that if you loop a the same VLAN into itself that it does not detect a loop? Or are you trying to detect loops across VLANs?
Patrick, yes if vlans protocol is configured as IP, then ELRP aint working. Its noticed in EXOS_Concepts_Guide also pointed here:
https://community.extremenetworks.com/extreme/topics/protocol_based_vlans-dgjyu

David i know it would work, but then checking configuration will be harder, because command show port will show always something like that 🙂

# show ports
Port Summary Monitor Mon Jan 18 14:34:13 2016
Port Display VLAN Name Port Link Speed Duplex
# String (or # VLANs) State State Actual Actual
==================================================================
2:1 (0002) E A 1000 FULL
2:2 (0002) E A 100 FULL

Thats why im asking about configuring protocol ip
Userlevel 7
Hi Michal, were you able to get this working? It might be best to open a case with GTAC so that further investigation can be done.

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