E-SRST Shared Line Limitations

[C4813Evans]

Most of our sites make use of Shared lines for incoming calls from the public which works great when all the phones are registered to our CUCM but when we loose our WAN and drop into E-SRST not all the phones configured with the Shared Lines will ring or be able to answer an incoming call on that line.  In our test lab I am able to simulate this problem and have narrowed it down to what appears to be a  limitation, only the first 16 phones that register in E-SRST get the shared line.   All other phones that register after that still show the line on the phone and work with the exception that the shared line does not ring and they can't answer incoming calls on that line.  Does anyone know if this is a hard limitation or any work a round in E-SRST Config??

Routers: 4331's and 2911's

Phones: 7841's and 8851's running SIP firmware

Sample Config below with IP's and DN's removed

voice register global
 mode esrst
 no allow-hash-in-dn
 system message "Phone Running in Failover Mode"
 max-dn 30
 max-pool 22
!
voice register dn  1
 number xxxxxxxx
 shared-line max-calls 4
!
voice register dn  2
 number xxxxxxxx
 shared-line max-calls 4
!
voice register pool 5
 id network xxx.xxx.xxx.xxx mask xxx.xxx.xxx.xxx
 preference 2
 no digit collect kpml
 voice-class codec 1
 busy-trigger-per-button 4
!

[R0g22]

I believe each shared dn can support a maximum of 16 calls, so what you see if the way it has been designed.
If you do a "shared-line max-calls ?", what do you see as the upper threshold ?

[C4813Evans]

Thanks

It does show <2-16> as the acceptable range
would be nice if there was away around this
such as specify in the config MAC's or Device Names of priority phones to we could guarantee the most important phones will get the shared line and be able to answer incoming calls instead of it being random 16 phones that register first.

[R0g22 · Accepted solution]

AFAIK there is no way to prioritize this. That is a limitation. You can get a PER going through your AM to either increase the threshold or have a way to put in preference.

While writing that, I had a thought though.