How to configure EAPS with CFM/OAM?

[PeterK]

How can I configure CFM/OAM basicly between 2 switches and together with EAPS for faster ring recovery, when I have a thrid-party switch in ring?
I read user/concept guide, command reference guide and older ENA/ENS Guides, but this doesn't help my.
Can some post a list of commands I need to use?

[Erik_Auerswald]

On the platforms with hardware accelerated CFM (e.g. X460) you can use a much faster rate for the CCMs.

[PeterK]

Hi Henrique,

thanks for your reply. Thats the fact...

The big 2 points in a ring:
- detecting link-loss between 2 or more 3rd party devices & ring-recovery
- detecting "no traffic-forwarding" without link-loss on 1 or more 3rd party devices & ring-recovery

Of course reducing hello-paket time or cfm-pdu will create higher usage on control-vlan, but it's the same on both mechanism.

When I started this threat, I thought I definitely need cfm for fast-ring-restore with 3rd party devices.

Currently, cfm doesn't really make a sense for me, because in default it's not faster than "eaps-native" and both timers working with 1 second.

From command-reference guide it's recommended to NOT set cfm-pdu / ccm-paket smaller than 1 second.

On EAPS-hello-paket I have not such recommended restriction.

That's why I currently not see a sense for cfm, or do I forget something or didn't see something?

[Henrique]

Hi Peter,

Let's take the following diagram as an example:

----(blocked_port)---SW1---(primary_port)-----DWDM-----DWDM-----SW2

Let's say the RX path between DWDMs went down. TX is still up. What's the direction for EAPS PDUs? TX through primary_port till SW2.

That flow for control_vlan will still be OK and Master node won't converge. Since blocked port is still in place, the Master node won't have data communication (expect for control_vlan) with other switches.

CFM is bi-directional and EAPS PDUs is unidirectional.

That's one situation that CFM is recommended.

PS: Even that DWDM could take all the path down, there could be some other situations similar to that one where CFM might be necessary.

Hope it helps.

[Henrique]

Hi Peter, when using 3rd party devices you have some situations:

When a link-down happens in a Transit node, it will send a link-down message to Master and convergence process starts.

• If you have two 3rd party devices connected together and the link between them goes down, you should use CFM to speed up the convergence process since no link-down message will be sent from Transit nodes.
• If you have two or more 3rd party devices that always connect to an EAPS device, any link-down will be noticed and advertised by the transit node. Ex: EAPS device----- 3rd party -------EAPS device ----- 3rd party

Regarding the ring-restore, it's based on the EAPS hello time (1s) through the control vlan.

To speedy up this you can change the hello time from 1 second (default) to milliseconds as follows:
configure eaps name hellotime milliseconds

However this will result in additional process usage and more EAPS ring traffic.