Clarifying EAPS Node States during Link Failure

[Zawgyi]

Hi everyone,
Normal state is complete. Should be Master node state failed or protection mode when one of link is broken? Is it correct?

[Luis_Agner · Accepted solution]

Your understanding of the logic is correct, but we need to clarify the exact EXOS (EAPS) terminology for technical accuracy:

Normal State: Yes, when all ring links are up, the Master node blocks its secondary port to prevent Layer 2 loops. The official state is Complete.

Broken Link: Yes, if any link in the ring breaks, the Master node detects the failure, unblocks its secondary port to restore traffic, and changes its state to Failed.

"Protection Mode": While the protocol is actively protecting the network, there is no operational state called "protection mode" in EXOS for EAPS (this term is usually associated with other protocols like ERPS/G.8032). The official and only state for the Master node during a link failure is simply Failed.

[FredrikB-NN2]

Here is an example of a master node when the ring is complete:

Name: ed123a Priority: Normal
State: Complete Running: Yes
Enabled: Yes Mode: Master
Primary port: 56 Port status: Up Tag status: Tagged
Secondary port: 2 Port status: Blocked Tag status: Tagged   <--- Note the Blocked state here

Example from a transit node:

Name: ed123a Priority: Normal
State: Links-Up Running: Yes
Enabled: Yes Mode: Transit
Primary port: 61 Port status: Up Tag status: Tagged
Secondary port: 57 Port status: Up Tag status: Tagged

If the ring fails at the master node, it will say "Link down". If the ring fails in some other point in the network, between two transit nodes, I'm not sure what the master will say, but likely something like "unblocked".

[Zawgyi]

Hi FredrikB-NN2

Thank you for your sharing.
Here is my output. 

Name: ed123a Priority: Normal
State: Failed Running: Yes
Enabled: Yes Mode: Master
Primary port: 56 Port status: Up Tag status: Tagged
Secondary port: 2 Port status: Up Tag status: Tagged

Should it become from blocked (secondary port) to Up? or Should it become from blocked (secondary port) to Forwarding?

Could you please clarify?