AAR and SRST

[andyap]

I am currently working on a project with 2 sites, Hq and Branch. CCM resides in the HQ while IP Phone from branches connect back to HQ CCM using the IP WAN link. Branches is actually using the DID number from the HQ.

At the remote site, the IP WAN router is also the SRST router with 2fxo port as backup. This solve the problem for outgoing call from remote sites when the WAN link down.

But at the other end, which is the HQ sites, outside people call the remote branches coming in from the HQ gateway and going out the IP WAN link to connect and people from HQ only call the extension no to reach the branch.

I've configure AAR to route the extension at the remote site to the PSTN if not enough bandwidth. But what happen if the WAN link is broken? The AAR will not kick-in since the phone is not register at all.

So is there anyway that I can backup the IP WAN and to re-route all the call to PSTN when the IP WAN is down.

Thanks

[gene]

The problem is you need an IP connection to keep the SCCP connection up. You need to either re-establish the IP connection by a dial backup with BRI, VPN or something or have some DID lines terminate at the remote site. Then SRST will allow incomming calls.

[swisslifefr]

Hi,

I've actually the same problem; let me explain.

One HQ office having the CCM in it, one branch office with a 2801 router (srst with a vic2-2fxo); as previously said, everything works fine for the outgoing calls from the branch office passing by the fxo card if the wan link between the offices goes down (the phones register on the srst router...).

But, the thing that doesn't work is the following :

When the wan link goes down, the phone registers itself on the srst router; ok.

The CCM discovers it's not registered on it anymore and should use the prefix digits (branch office pstn phone number) using the AAR Group ?

Did I understand what to be has understood, or did I make a mistake since it doesn't work...

Hope you can help me with this case,

[jleon22]

The current version of CCM's AAR does not work like that. AAR will only check for bandwidth availability and is not network aware that the WAN link is down. We have a similiar scenario. There might be something in the works in CCM 4.2 that prefix digits when phones get unregistered.

[michael_davis]

Seems to me you could create a translation pattern, placed in the partition that changes the DN to dial the remote site main number.

For example, for extensions 42xx (SRST site extension range), translate them to 912125551212 or whatever the main FXO number is.

This assumes that phone DNs reside in a preferable partition (not ) so they are found first when the phone is registered.

The bigger problem is, you need DID numbers or TCL AA functionality at the SRST site so that when the call is transferred by CCM to the SRST gateway, the gateway has to figure out which IP Phone gets the call. A DID can map to an extension or AA can prompt the caller for an extension.

Since you are using FXO, you should consider using srst_CISCO.2.0.0.0.tcl which I believe is found in:

http://www.cisco.com/cgi-bin/tablebuild.pl/ip-key

srst-2.0.zip

Implementation instructions can be found within the script itself.

Let me know if this helps by rating the post.

Michael

[andyap]

I've try the above method, it's not working as the callmanager will look for translation pattern before going for internal DN. Therefore, the translation pattern will always apply.

[andyap]

sorry my mistake, I configure the translation pattern wrongly.

Now i've reconfigured the above scenario and when the phone unregistered (unplug from the switch) the translation pattern still not kicking in.

when I dial the phone extension, it give me a fast busy tone.

[michael_davis]

Seems to me you could create a translation pattern, placed in the partition that changes the DN to dial the remote site main number.

For example, for extensions 42xx (SRST site extension range), translate them to 912125551212 or whatever the main FXO number is.

This assumes that phone DNs reside in a preferable partition (not ) so they are found first when the phone is registered.

The bigger problem is, you need DID numbers or TCL AA functionality at the SRST site so that when the call is transferred by CCM to the SRST gateway, the gateway has to figure out which IP Phone gets the call. A DID can map to an extension or AA can prompt the caller for an extension.

Since you are using FXO, you should consider using srst_CISCO.2.0.0.0.tcl which I believe is found in:

http://www.cisco.com/cgi-bin/tablebuild.pl/ip-key

srst-2.0.zip

Implementation instructions can be found within the script itself.

Let me know if this helps by rating the post.

Michael

[michael_davis]

Well, the trans-pattern approach seemed like a good idea, but so far, I haven't gotten it to work. Playing with call-forward scenarios now.

That said, the TCL information is something I've done before and know that it works.

Will keep you posted.

Michael

[andyap]

haven't try the scenario will try it later. But I'm going for another solution, i.e to have an ADSL line backup to the internet. when the least line down, the adsl router will establish a vpn connection back to the hq site and the phone will route back via the vpn.

Going to implement it this month, hopes everything ok.