[cisco-voip] Route Group Distribution Algorithm and SIP

[Wes Sisk]

There are a few factors that affect hunting through route groups and route lists.  I believe the most prescient to your situation are:

* Advanced CM service parameters for "Clusterwide Parameters (Route Plan)".  These include:
** Stop Routing on Out of Bandwidth Flag
** Stop Routing on Unallocated Number Flag
** Stop Routing on User Busy Flag
** Stop Routing on Q.931 Disconnect Cause Code

These may allow or inhibit routing based on cause code.

The signaling to GSM gateway is not clear to me.  There is a limitation in CUCM that it will stop hunting once media is locked on an endpoint:
CSCsb22055    CCM should reroute to next route list member after media established

It is not possible to affect this behavior currently.  It is however possible to affect media lock to avoid this situation.  For example see:
CSCse70721    Need ability to delay media until alerting, progress, connect, or PI

There are also service parameters and gateway configuration options that affect when media cut through is attempted. See "Retain Media on Disconnect with PI for Active Call" and similar.


So, why does hunting stop in your scenario? If for cause codes use #1 above.  If for media, see #2 above.  If for some other reason then we will need some more information.

Regards,
Wes

On Oct 19, 2011, at 4:32 AM, Nathan Reeves wrote:

Scenario as follows:
 - 2 GSM Gateways located in different offices. (2N Voiceblue Enterprise)
 - 2 SIM Cards in each gateway.
 - GSM Gateways are connected via SIP trunks.
 
What I want to do is setup route patterns for specific (company plan) mobiles so that when calls are made to these numbers they head out the GSM gateways.  I'm having issues getting a failover scenario to work with this though.  If two calls are in progress on GSM Gateway 1, calls should be attempted on GSM Gateway 2.  If both channels are in use on Gateway 2 then we should push the calls out PSTN.
 
I've attempted to place the two Gateways in one Route group, but with two calls on Gateway 1, calls don't proceed to Gateway 2.  From logs I'm seeing on Gateway 1 that it's passing the following back to CUCM:
 
10/19/2011 20:06:08.38 <SIP> Rejecting incomming call. Reason 11
10/19/2011 20:06:08.39 <SIP> To: 10.10.10.1 SIP/2.0 480 Temporarily Unavailable
 
I've looked into using Locations and AAR but I'm not sure I'm going to get what I want with that setup.
 
Anybody have any ideas if something like this failover is possible? How does the the Distribution algorithm work in the situation of SIP Trunks and detection of failure / when we should proceed to the second gateway in the RG?
 
Thanks
 
Nathan
_______________________________________________
cisco-voip mailing list
cisco-voip at puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-voip

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20111019/d7681c2e/attachment.html>