Help! alternate routing within big distributed system

[rejackson]

I called it a big distributed system because Avaya called it that it some doc I was reading. It is an 8700 with media gateways scattered around the country and LSPs (8300s) in each remote MG. The links between the locations are VoIP but they are not trunks. Now our "business partner" reseller tells us that this system cannot provide alternate routing if the VoIP link is down. The LSP will run the remote MG for in/out calls to the PSTN and to other phones attached to the MG. But there is no routing capability to make it use the PSTN if someone dials an extension at another office.

Right now if you are on an MG that is connected to the 8700 and dial an extension that is on an MG that has lost its connection it goes straight to voice mail. If you are on the isoloated MG dialing an extension on another MG it gets a busy.

Can anyone confirm this limitation or maybe suggest some ways around it?

 

[irisngen]

in the 8700, you have to add the trunks groups of the gateways pstn lines, this way when operating in lsp mode, those trunks will be in service & calls will route out over them.

 

[Dunstan]

Can you use IGAR ? That should provide what your looking for.

What release are you on?

Here is a short excerpt explaining how it is used....I have a large distributed system also with gateways all over the country. This works well.

Inter-Gateway Alternate Routing
Inter-Gateway Alternate Routing (IGAR) is designed for single-server systems that use the
IP-WAN to connect bearer traffic between port networks or media gateways. IGAR provides a
means of alternately using the public switched telephone network (PSTN) when the IP-WAN is
incapable of carrying the bearer connection.
IGAR may request that bearer connections be provided by the PSTN under the following
conditions:

The number of calls allocated or bandwidth allocated via Call Admission
Control-Bandwidth Limits (CAC-BL) has been reached

VoIP RTP resource exhaustion in a MG/PN is encountered

A codec set is not specified between a network region pair

Forced redirection between a pair of network regions is configured
IGAR takes advantage of existing public and private network facilities provisioned in a network
region. Most trunks in use today can be used for IGAR. Examples of the better trunk facilities for
use by IGAR are:

Public or Private ISDN PRI/BRI

R2MFC
IGAR provides enhanced Quality of Service (QoS) to large distributed single-server
configurations.
For more information, see Administration for Network Connectivity for Avaya Communication
Manager, 555-233-504

 

[irisngen]

IGAR works nicely also.

 

[rejackson]

Our Business Partner mentioned IGAR but said that it doesn't support the VoIP line down problem...

"In the latest release of ACM, R3.1, if a limit is set for CAC and a call exceeds that limit a newer feature, IGAR, would route a call over the PSTN. If the link was down and the remote location was in LSP mode, even in R3.1, IGAR would not be applicable and the calls would follow the administered coverage path."

Is he wrong????

 

[Dunstan]

Look at the description...it speaks to exhausted (read also unavailable) resources..

I would have another talk with your vendor. I am not sure about the interactions with LSP's as we have only ESS out in the field.