WAN Failover to T1 PRI - What's missing? Picture attached.

RalphSmithIII · ‎02-28-2013

Hi everyone, I'm troubleshooting a small issue and I can't seem to wrap my head around how this specific scenrio is supposed to be configured.

I'm tryign to figure out how to get one Cisco 2811 ISR with multiple 2MFT-T1 cards in it to pass calls between the different voice ports.

For example, if you look at the diagram, I am just setting up failover. WAN comes down and calls should reroute over the PRI via the PSTN to the Remote site. My question is, how does the simulated PSTN need to be configured to allow calls coming in from the HQ site on one physical/logical voice port and pass the call out to another physical/logical voice port to reach a phone on the Branch router?

I have all my dial-peers in place and are translating the 4 digit extensions from the local sites to 10 digit numbers when hitting the PSTN. On the PSTN I'm translating the 10 digits back down to 7 digit local numbers for each site and on each site taking the numbers down to 4 digits to ring the phones on their internal extensions.

What I'm not clear on is how does the PSTN router route the calls between the two PRI's? I'm seriously having a brain fart, again. Calls from the PSTN can be placed to each site just not between the PSTN from each site.

acampbell · ‎02-28-2013

Ralph,

Something like this will do the trick :-

!

hostname PSTN

!

dial-peer voice 2000 pots

desc *** TO BRANCH ***

destination-pattern 818831...

incoming called-number .

port 0/1/0:23

forward-digits all

!

dial-peer voice 8000 pots

desc *** TO HQ ***

destination-pattern 2125472......

incoming called-number .

port 0/0/0:23

forward-digits all

!

Regards,
Alex.
Please rate useful posts.

Regards, Alex. Please rate useful posts.

RalphSmithIII · ‎02-28-2013

I think there were a couple of small errors in your reply Alex but correct me if I'm wrong.

Here is what I have configured on the PSTN Router:

dial-peer voice 101 pots

destination-pattern 831....

port 0/0/0:23

prefix 831

!

dial-peer voice 322 pots

destination-pattern 547....

port 0/1/0:23

prefix 547

!

dial-peer voice 3002 pots

destination-pattern 2125472...

incoming called-number .

port 0/1/0:23

forward-digits all

!

dial-peer voice 3001 pots

destination-pattern 8138311...

incoming called-number .

port 0/0/0:23

forward-digits all

!

dial-peer voice 1 pots

incoming called-number .

direct-inward-dial

3002 is used to route calls via the PRI to the Branch location

3001 to the HQ location based on the topology

When I debug q931 from each router:

HQ OUTBOUND to PSTN

Mar 1 03:47:41.587: ISDN Se0/0/0:23 Q931: Applying typeplan for sw-type 0xD is 0x2 0x1, Calling num 8138311001

Mar 1 03:47:41.587: ISDN Se0/0/0:23 Q931: Sending SETUP callref = 0x0083 callID = 0x8004 switch = primary-ni interface = User

Mar 1 03:47:41.587: ISDN Se0/0/0:23 Q931: TX -> SETUP pd = 8 callref = 0x0083

Bearer Capability i = 0x8090A2

Standard = CCITT

Transfer Capability = Speech

Transfer Mode = Circuit

Transfer Rate = 64 kbit/s

Channel ID i = 0xA98384

Exclusive, Channel 4

Progress Ind i = 0x8183 - Origination address is non-ISDN

Calling Party Number i = 0x2180, '8138311001'

Plan:ISDN, Type:National

Called Party Number i = 0xA1, '2125472001'

Plan:ISDN, Type:National

Mar 1 03:47:41.607: ISDN Se0/0/0:23 Q931: RX <- RELEASE_COMP pd = 8 callref = 0x8083

Cause i = 0x8081 - Unallocated/unassigned number

PSTN INBOUND from HQ

Mar 1 03:53:39.022: ISDN Se0/0/0:23 Q931: RX <- SETUP pd = 8 callref = 0x0083

Bearer Capability i = 0x8090A2

Standard = CCITT

Transfer Capability = Speech

Transfer Mode = Circuit

Transfer Rate = 64 kbit/s

Channel ID i = 0xA98384

Exclusive, Channel 4

Progress Ind i = 0x8183 - Origination address is non-ISDN

Calling Party Number i = 0x2180, '8138311001'

Plan:ISDN, Type:National

Called Party Number i = 0xA1, '2125472001'

Plan:ISDN, Type:National

Mar 1 03:53:39.030: ISDN Se0/0/0:23 Q931: TX -> RELEASE_COMP pd = 8 callref = 0x8083

Cause i = 0x8081 - Unallocated/unassigned number

Basically same output from the branch location to the PSTN.

As you can see, I'm translating the calling party number from the HQ location from the 4 digit 1001 to the 10 digit 8138311001. I also wrote a translation for the Called Party Number.

On the PSTN however, I don't have any translations because I'm send the 10 digits to the Branch location. At the Branch location and HQ location I'm stripping off the first 7 digits using a translation rule.

Example:

voice translation-rule 1

rule 1 /^$1...$$/ /813831\1/

!

voice translation-rule 2

rule 1 /^831/ //

!

voice translation-rule 3

rule 1 /^$2...$$/ /212547\1/

!

voice translation-profile CALLID_OUT

translate calling 1

!

voice translation-profile PSTN_ALT_OUT

translate called 3

!

voice translation-profile PSTN_IN

translate called 2

Applied to the alternate PRI dial-peer on the HQ router:

dial-peer voice 302 pots

translation-profile outgoing PSTN_ALT_OUT

preference 2

destination-pattern 2...

no digit-strip

port 0/0/0:23

forward-digits all

I feel this should work but haven't found a solution yet as to why it does. I may need to translate at the PSTN and send down 7 digits instead of 10 to the branch location but it doesn't appear the PSTN router is sending anything to the branch location when I place a call from the HQ router using a 4 digit number of the branch location.