Scenario#11 – Getting ‘unknown number’ when making outbound calls

I came across this issue last week.

When making outbound calls, Instead of their DDI, the called party was getting ‘unknown number’.

The system was on CME 7.0. I jumped on the gateway and started dissecting the bits and pieces. It was quite a long running config so I just took out what was important. The config below is useful to understand how translation rules, dialpeers and Trunk group work.

This rule to prefix incoming calling party number with 9, 90, 900 depending upon the type.

voice translation-rule 1

rule 1 /^\(.*\)/ /9\1/ type subscriber subscriber
rule 2 /^\(.*\)/ /90\1/ type national national
rule 3 /^\(.*\)/ /900\1/ type international international

!

This rule is changing the incoming DDI (164470) to Voicemail Pilot.

voice translation-rule 2
rule 1 /^164470/ /4000/

!
voice translation-rule 3
!
voice translation-rule 4
!

!

voice translation-profile BT-ISDN2e-IN
translate calling 1
translate called 2

!

voice translation-profile BT-ISDN2e-OUT
translate calling 3
translate called 4

!

I found two rules which had nothing in them. This was the reason their DDI was not going across.
As you can see that in translation-profile BT-ISDN2e-OUT those rules are referenced to change the ANI
of calling-party.They were just sending 4-digit extension which for PSTN was unknown and hence the issue.
After having a look at their ephone-dn's and the debug isdn q931 for inbound call, I created the following
rule to go under voice translation-rule 3. There was no need for translation-rule 4 so I deleted it.
They had following DDI range.

[1559 - XXXXX788559]
[1550 - XXXXX788550]

Where XXXXX is the City code.

Voice translation-rule 3
rule 1 /^1\(...$\)/ /788\1/ type any sub plan any isdn

-- Check ephone-dn at the end

Further I found customer was using Trunk groups. Trung groups eliminate the need of redundant POTS dialpeers with preference command for different E1 or BRI circuit. You can make just one trunk group

They have 4x BRI while only 2x used for incoming and outgoing calls.

voice-port 0/1/1
translation-profile incoming BT-ISDN2e-IN
translation-profile outgoing BT-ISDN2e-OUT
compand-type a-law
cptone GB

!
voice-port 0/2/1
translation-profile incoming BT-ISDN2e-IN
translation-profile outgoing BT-ISDN2e-OUT
compand-type a-law
cptone GB

!
FXS ports#

voice-port 0/3/0
cptone GB
!
voice-port 0/3/1
cptone GB

A trunk group was created for BRI 0/1/1 and BRI 0/2/1 – these two will be referenced in all POTS dialpeers further below.

!
trunk group BRI
!

interface BRI0/1/1
no ip address
isdn switch-type basic-net3
isdn point-to-point-setup
isdn incoming-voice voice
isdn static-tei 0
trunk-group BRI 3
!

interface BRI0/2/1
no ip address
isdn switch-type basic-net3
isdn point-to-point-setup
isdn incoming-voice voice
isdn static-tei 0
trunk-group BRI 3

Dialpeers needed in UK for external calls. See how trunk group has been mentioned in all POTS dialpeers. This will make calls to go through either of BRI, which ever is available.

dial-peer voice 1 pots
trunkgroup BRI 3
description ** Emergency **
destination-pattern 999
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
forward-digits all
!

dial-peer voice 2 pots
trunkgroup BRI 3
description ** Emergency **
destination-pattern 9999
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
forward-digits 3

!

dial-peer voice 3 pots
trunkgroup BRI 3
description ** Emergency **
destination-pattern 112
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
forward-digits all

!

dial-peer voice 4 pots
trunkgroup BRI 3
description ** Emergency **
destination-pattern 9112
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
forward-digits 3

!

dial-peer voice 5 pots
trunkgroup BRI 3
corlist outgoing call-local
description ** Local Numbers **
destination-pattern 9[1-9]…….
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
forward-digits 8

!

dial-peer voice 6 pots
trunkgroup BRI 3
corlist outgoing call-standard
description ** UK numbers **
destination-pattern 90[1-8]T
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
prefix 0

!

dial-peer voice 7 pots
trunkgroup BRI 3
corlist outgoing call-international
description ** International **
destination-pattern 900T
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
prefix 00

!

dial-peer voice 8 pots
trunkgroup BRI 3
corlist outgoing call-unrestricted
description ** Unrestricted **
destination-pattern 9T
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
!

dial-peer voice 9 pots
trunkgroup BRI 3
corlist outgoing call-directory
description ** 118 services **
destination-pattern 9118…
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
prefix 118

!

dial-peer voice 15 pots
trunkgroup BRI 3
incoming called-number .
direct-inward-dial
!

VOICEMAIL:

dial-peer voice 1000 voip
description ** cue voicemail pilot number **
destination-pattern 4000
session protocol sipv2
session target ipv4:10.10.100.2
incoming called-number 400T
dtmf-relay sip-notify
codec g711ulaw
no vad
!

dial-peer voice 1010 voip
description ** cue Prompt Management pilot number **
destination-pattern 4010
session protocol sipv2
session target ipv4:10.10.100.2
dtmf-relay sip-notify
codec g711ulaw
no vad

!

dial-peer voice 1020 voip
description ** cue AutoAttendant pilot number **
destination-pattern 4020
session protocol sipv2
session target ipv4:10.10.100.2
dtmf-relay sip-notify
codec g711ulaw
no vad

!
Some ephone-dn:

They were using Primary as internal extension and Secondary as 6-digit number from DDI Range. BT will send call to gateway as ‘788551’ which can then ring this phone as the number is configured as secondary. This is also necessary if you want to ring different for Internal and external calls. They could have used a Translation rule as well to convert incoming calls to 4-digit Internal extensions.

ephone-dn  1  dual-line
ring internal primary
number 1551 secondary 788551
pickup-group 500
label Joe Bloggs (1551)
description XXXXX788551
name Joe Bloggs
call-forward busy 4000
call-forward noan 4000 timeout 15
corlist incoming User-unrestricted
huntstop channel

!

!

ephone-dn  2  dual-line
ring internal primary
number 1552 secondary 788552
pickup-group 500
label Azfar Siddiqui (1552)
description XXXXX788552
name Azfar Siddiqui
call-forward busy 4000
call-forward noan 4000 timeout 15
corlist incoming User-unrestricted
huntstop channel
!