FXS, Dial Peer questions

Unanswered Question
Dec 11th, 2008

I have a site that has a PRI and some associated DID numbers.

This site is using FXS ports for

A FAX Machine

A Modem

A second device that only dials out

I am trying to sort out exactly what is going on with the config.

Some of it is obvious, but a couple of things are not.

For example, I see the FAX and Modem in the config and it makes sense that these things are configured on voice-port 0/1/0 and 0/1/1. I can see the calls when these devices are being used.

What I do not see are the port labeled "Overhead Paging" (dial-peer 42, 0/1/2)and the other port that has no label (dial-peer 43, port 0/1/3)

The building is using a device that calls out only and when the call is made, it shows up as the main number for the site which is associated to the PRI.

My questions are:

Could a device be attached to voice-port 0/1/3 and make a successfuil outbound call with what is shown here?

Are the dial peers 99901x doing anything?

What is the "POTS" designation doing on the dial-peers?

voice-port 0/0/0:23

!

voice-port 0/1/0

description Modem 904-321-1234 (site DID)

!

voice-port 0/1/1

description Fax 904-321-3456 (site DID)

!

voice-port 0/1/2

!

voice-port 0/1/3

description Paging port

!

voice-port 1/0/0

!

voice-port 1/0/1

!

voice-port 1/0/2

!

voice-port 1/0/3

!

voice-port 1/0/4

!

voice-port 1/0/5

!

voice-port 1/0/6

!

voice-port 1/0/7

!

voice-port 1/0/14

!

voice-port 1/0/15

!

voice-port 1/0/16

!

voice-port 1/0/17

dial-peer voice 40 pots

description Order line

service mgcpapp

destination-pattern 3211234

port 0/1/0

!

dial-peer voice 41 pots

description FAX machine

service mgcpapp

destination-pattern 3213456

port 0/1/1

!

dial-peer voice 42 pots

description Overhead Paging

service mgcpapp

destination-pattern 3300

port 0/1/2

!

dial-peer voice 43 pots

service mgcpapp

port 0/1/3

!

!

dial-peer voice 999010 pots

port 0/1/0

!

dial-peer voice 999011 pots

service mgcpapp

port 0/1/1

!

dial-peer voice 999012 pots

port 0/1/2

!

I have this problem too.
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allan.thomas Thu, 12/11/2008 - 13:49

Hi Richard,

There appears to be some duplication with the regards to the POTs dial-peers here in the configuration.

The dial-peers begining 999 are usually automatically configured and associated with MGCP controlled ports when configured through CallManager:-

dial-peer voice 999010 pots

port 0/1/0

!

dial-peer voice 999011 pots

service mgcpapp

port 0/1/1

!

dial-peer voice 999012 pots

port 0/1/2

The strange thing about these is that the service mgcpapp has been removed. However these voice-ports are still associated with mgcpapp on the following dial-peers instead, with the exception of port 0/1/3:-

dial-peer voice 40 pots

description Order line

service mgcpapp

destination-pattern 3211234

port 0/1/0

!

dial-peer voice 41 pots

description FAX machine

service mgcpapp

destination-pattern 3213456

port 0/1/1

!

dial-peer voice 42 pots

description Overhead Paging

service mgcpapp

destination-pattern 3300

port 0/1/2

If a device is connected to port 0/1/3, then it possible for this device to receive inbound calls, make outbound calls or both.

You should find that these voice-ports are configured on the appropriate gateway within CallManager, and will also have an attendant DN configured. The port should also indicate whether the port is for inbound, outbound or both.

The destination-pattern would be configured on a pots dial-peer specifically for SRST fallback if configured. Otherwise there is no use for the command as the port is controlled by mgcp, and the DN or destination-pattern is in CallManager.

Hope this helps.

Allan.

wilson_1234_2 Thu, 12/11/2008 - 17:25

Thanks allan,

Can you tell me how I would get to the place withing call manager you are talking about?

I am thinking since the existing router will be moving to the new site and the IP Addressing insternally will be the same, nothing needs to be done other than just move the router to the new PRI and port the numbers over and everything should be fine (as long as the devices go to the correct FXS ports).

Also, if you didn't notice, this is from the same branch that will be moving soon.

Your assistance was very helpful on the earlier post.

I used your sample config and it worked like a charm.

Many thanks.

allan.thomas Fri, 12/12/2008 - 00:52

Hi Richard, your welcome.

Thanks for the appreciation, glad to hear that you were able to test the PRI successfully with the sample config I provided.

Apologies, this is from memory, within the Device menu in CallManager admin, select Gateways and when the page displays click find. A list of configure gateways should be returned.

I suspect that there will be more that one, so click on the gateway which has the correct IP address or HostName.

When the page is displayed with the gateway, on the righthand side you should see all the FXS endpoints. Simply click on one of these ports, and from here the DN will be evident.

If the LAN IP addressing is remaining static, and the WAN interfaces, then yes you need to change anything. However if the WAN is IP addressing is changing, you will probably have to change your default-route.

Hope this helps.

Allan.

wilson_1234_2 Fri, 12/12/2008 - 08:20

Thanks Allan,

I found the gateway and the endpoints.

I see in the upper left corner the FXS card and each port is associated to a number.

The two devices that accept inbound calls are associated to a DID number for that branch.

The other two ports are just associated to a 4 digit extension of that branch, which makes senmse because they do not need to accept inbound calls.

What I do not see is how did the numbers get associated to the ports?

There is nothing on the page of each endpoint that would show that.

At the bottom the only thing that would come close is "Port Information" and the DN is left blank on all of them

Port Information

Prefix DN (left blank)

Num Digits 0

Expected Digits 0

SMDI Port # 0

Also, did you say that since this was configured in Call Manager, that takes precedence over the internal router config?

Where is the router is that configured?

allan.thomas Fri, 12/12/2008 - 08:53

Hi Richard, when configure an FXS port from within CallManager from new, there is a link on the page to add a new line. No different from when you add a line appearance to Phone.

This DN number would only normally appear in CallManager and is not configured in the router. When Callmanager receives an incoming for this DN is recognises which port is associated with the DN.

As I have said before, disregard the fact that there is a destination-pattern on the POTs dial-peers.

This is not configured by CallManager when the configuration is dowloaded to the gateway. This must have been added additionally, and the only reason for this is for fallback to H.323(SRST). In this scenario the signalling is not backhaul to CallManager and instead the gateway matches the outgoing dial-peer using the destination-pattern when the CM is down.

Hope this helps.

Allan.

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