Avaya MG and LSP Mode

[FXLL]

Hi Comunity,

I have a question about the Avaya MGs and the LSPs.

Do you know what is the time that an Avaya MG waits before to go to LSP mode without a Recovery Rule set on it?

I mean, we have several G450 in different locations, and we are having issues with the network side (ISP).
they have network flaps from less than 3 mins, all of my G450 have the Recovery Rule set in 3 mins.

The Customer is requesting to remove the Recovery Rule to have the MG goes to LSP and we will manually register into the CM once the Network is stable.

Now I being asked of what is the time that the MG is going to wait until it goes to LSP without a Recovery Rule.

display system-parameters mg-recovery-rule 1
SYSTEM PARAMETERS MEDIA GATEWAY AUTOMATIC RECOVERY RULE
Recovery Rule Number: 1
Rule Name:
Migrate H.248 MG to primary: immediately
Minimum time of network stability: 3


Thanks in Advance--

 

[kyle555]

Recovery rules only affect failback to core, not failover to LSP.
Recovery rule with 3 mins means the gateway will only come back from the LSP to the core after 3 minutes of network stability and you can't set it lower than that in case your WAN is flapping.

Without a recovery rule, the gateway in LSP mode will never migrate back.

The recovery rules can be immediate after X minutes, or with 0 calls, or time of day based, or either after hours or with 0 calls.


As far as how long it waits to go to LSP mode, do a "show rec" in the gateway.
005(super)# show rec

RECOVERY TIMES
--------------------------------
Primary Search : 3
Total Search : 10
Transition Point: 1

So, if you show mgc list, and you have entries 1.1.1.1,2.2.2.2,3.3.3.3, then the gateway will try 1.1.1.1 for 3 minutes, then the 2nd entry is past the transition point of 1 (to say, only the 1st of 3 entries is considered 'primary'), at which point it will try entry 2,3,1,2,3,1,2 for 1 minute each for a total of 10 mins before it reboots itself and starts over. I think that's how it works. I can't remember if it will try the 1st entry ever again after 3 minutes after it passed it's transition point until it reboots, but I think that's how it works.

If you want to control how long the gateway waits before trying LSP mode, then have a primary search of that length and ensure the LSP's entry in the mgc list is after the transition point.

 

[kyle555]

*you also have your link loss delay timer in the core CM. see pg 27 -

https://downloads.avaya.com/css/P8/documents/100011997

It's the time that the core CM keeps the calls up on the failed gateway in the event it re-registers.

In theory, if you have a gateway with stations and trunks, and a call comes in from one of those trunks to a station and they are connected, and the WAN flaps - despite not affecting the media path between the station and trunk, if the gateway recovers within the time of the link loss delay timer, then call features can be re-established. That could be a valid concern for your environment as well if the WAN is unreliable.

 

[FXLL]

Thank You Kyle.

That helped me to understand what is the issue here,
they have the Recovery Rule Set to Migrate H.248 MG to primary: immediately

So they are dropping calls each time that there is a Flapp and then the Network is stable for more than 3 mins.

Thanks Again.

 

[kyle555]

so then you don't want to migrate back as soon as the network has been stable for 3 minutes. I'd say maybe a recovery rule of 0 active calls is better.

 

[montyzummer]

You could opt for turning off the automatic recovery and then you are in control , when you are confident the WAN is stable you issue the "enable mg-return" command , this will gracefully return the gateways to core , this command stays active for 60 min , in a PN this is similar to the "get forced-takeover ipserver-inerface" , its really down to personal preference but I genraly opt for the manual recovery or a recovery rule that specifies a minimum time of WAN stability and 0 active calls to ensure minimal impact , the only time this is a problem is on a 24hr operation.

ACSS (UC/SBCE/SM/SME)

Not that they mean a thing anymore , get a brain dump pass the test crash the system.

 

[FXLL]

Thank You Both,

That clarify all my concerns about this topic.

Kind Regards-