10-23-2003 11:42 AM - edited 03-13-2019 02:14 AM
Here's my setup:
CCM 3.3 at central location
T1's to remotes
2621's at remote sites with 2 FXO ports
SRST works as far as phones failing over, registering with 2621, and being able to dial 9 and get dial-tone from one of the FXO lines. Is it possible for CallManager to route calls to this site through PSTN when the WAN link fails? Central Site has 2 PRI circuits on a 6009 for outbound/inbound calls.
10-23-2003 11:45 AM
Yes, it is possible with 3.3, using the AAR feature (Automated Alternate Routing).
10-23-2003 12:07 PM
Could you elaborate a bit? I had looked into this, but Cisco's documentation on this one is a bit light. The AAR config is just an alternate prefix digit. Do I need AAR plus a set of translation patterns to get the call out to my remote PSTN line? Additionally, I can only find AAR Group settings on individual lines. Is there a way to apply this to a broader scope?
10-23-2003 03:57 PM
I just noticed you said "when the wan link fails" I was thinking when the wan is low on bw. AAR will not work for a WAN failure. There is no automatic way to fallback to the pstn in the case of a wan failure.
The way AAR works is that if the bandwidth reservation fails, AAR is invoked and looks at the source AAR group and the destination AAR group. It sees what digits needs to be prepended, and then automatically places the call again using the new number.
You usually create 1 aar group for every physical location. Then, for each AAR group, you define what digits you need to prefix in order to reach the other AAR groups over the pstn. This is usually 9+1+area code+office code (assuming 4 digit extensions).
If your IP phones have a External Phone number mask defined on the line, then this is automatically prepended, so you may just need to prepend 9+1 for all of your locations.
10-23-2003 04:24 PM
That's what I thought. This is really one of the few weaknesses I've found with SRST(Survivable Remote Site Telephony). The remote site survives internally, but any inbound calls just go to voicemail.
05-27-2004 08:05 AM
SRST works perfeclty with DID nubmers at the remote branches. In the event of wan failure they can still receive and place calls. Depending on how many people are at these locations you may want to look at adding DID for them. Just a thought.
Geoff
05-27-2004 07:26 AM
Hi,
Is this also documented somewhere that you can use AAR on WAN/LAN link failures when u use on the remote sites SRST???
I want to rollout such design ,but I wanna be sure.
Regards,
Perry
10-23-2003 04:27 PM
nope cuurenly AAR would not work with a WAN failure. The feature is under development and on the reoad map where you would be able to route call when the phones are gone down.
thx
imran
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: