Delay for outbound calls using FXO

[mrmarie]

Hi Guys,

We have a Cisco voice gateway with FXO, and faced an issue that after the number is dialed there is a few seconds delay before the call begins to ring about (11 to 13 Sec).

What could be causing the delay?

The Port Configuration

voice-port 0/0/0

ring number 2

no vad
caller-id enable

Thanks

[HARIS_HUSSAIN]

This is happening for incoming calls or Outgoing Calls.
If it is Incoming call from PSTN, We Need to find out if delay is from Provider or from Our Equipment.
Enable below debugs and make a test call. Note down the time between Call Dialed ---- Calls Hitting Gateway ( Generates the Debug) & Call Ringing on Phone.

Debug voip vtsp all
Debug vpm signal

[mrmarie]

Hi Haris,

I am tried to run debug commands as below and make test call "nothing happens within call". is there something i'm missing!!

Voice-Gateway#debug vpm signal
Voice Port Module signaling debugging is enabled
Voice-Gateway#debug voip vtsp all
voip vtsp all debugging is on

Thanks

[ranjithkumarpullaikodi100]

am lso facing the call dial delay 13-17 seconds.

[Arun Prakash Sharma]

Please try this with VG on global Command.

VG-HQ1#Conf t
VG-HQ1(config)#voice rtp send-recv
VG-HQ1(config)#voice-port 0/1/0
VG-HQ1(config-voiceport)#shutdown
VG-HQ1(config-voiceport)#timeouts interdigit 10
VG-HQ1(config-voiceport)#no shut
VG-HQ1(config-voiceport)#do wr
VG-HQ1(config-voiceport)#exit

It is because of overlapping on Dial-peer (check carefully). for H.323
Change T302 to 15000 to 500 in CUCM.

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Thank you,
Arun Prakash Sharma

[amjadhussam6639]

Thank you Arun it is working now.

I applied same command on my VG it is working fine. Noe delay is 3 sec only.

[ranjithkumarpullaikodi100]

Dear Haris,

I have FXO ports in 2 lines. am getting dial delay 13-17 seconds.

[Mohammed al Baqari]

Can you share the matched dialpeer.? This seems to be cause by interdigit
timeout timer which is by default 15 sec.

[mrmarie]

Hi Mohammed,

Here is the configuration:

voice-port 0/0/0
 ring number 2
 no vad
 connection plar opx 21
 caller-id enable
!
voice-port 0/0/1
 ring number 2
 connection plar opx 21
 caller-id enable
!
voice-port 0/0/2
 ring number 2
 connection plar opx 21
 caller-id enable
!
voice-port 0/0/3
 ring number 2
 connection plar opx 21
 caller-id enable
!
voice-port 0/1/0
 ring number 2
 connection plar opx 10
 caller-id enable
!
voice-port 0/1/1
 ring number 2
 connection plar opx 14
 caller-id enable
!
voice-port 0/1/2
 ring number 2
 connection plar opx 21
 caller-id enable
!
voice-port 0/1/3
 ring number 2
 connection plar opx 21
 caller-id enable
 !
 !
 !
 !
 --More--         !
mgcp behavior rsip-range tgcp-only
mgcp behavior comedia-role none
mgcp behavior comedia-check-media-src disable
mgcp behavior comedia-sdp-force disable
!
mgcp profile default
!
!
!
!
dial-peer voice 1 pots
 destination-pattern 9T
 port 0/0/0
!
dial-peer voice 1000 voip
 preference 2
 destination-pattern .
 session target ipv4:10.20.200.2
 codec g711ulaw
!
dial-peer voice 2 pots
 destination-pattern 8T
 port 0/1/0
!
dial-peer voice 3 pots
 destination-pattern 7T
 port 0/1/1
!
!
!
!
gatekeeper
 shutdown

[Maren Mahoney]

Post-dial delay is often due to variable-length calling issues. For instance, if you have a pattern such as 1234 and also a pattern 12345 in a PBX the system will wait for the interdigit timeout to expire before pathing the call. On a router, if the dial-peer that is sending the call to the FXO is configured with a "T" and the router is receiving digits on a digit-by-digit basis that can also cause post-dial delay.

How is the call being sent to the router? Is the originating device also on the router (CME or FXS), on a CUCM or on a 3rd party PBX? Also, can you show us the dial-peer that is sending the call to this port?

[mrmarie]

Hello Maren,

it's on CUCM, and here is the configuration:

voice-port 0/0/0
 ring number 2
 no vad
 connection plar opx 21
 caller-id enable
!
voice-port 0/0/1
 ring number 2
 connection plar opx 21
 caller-id enable
!
voice-port 0/0/2
 ring number 2
 connection plar opx 21
 caller-id enable
!
voice-port 0/0/3
 ring number 2
 connection plar opx 21
 caller-id enable
!
voice-port 0/1/0
 ring number 2
 connection plar opx 10
 caller-id enable
!
voice-port 0/1/1
 ring number 2
 connection plar opx 14
 caller-id enable
!
voice-port 0/1/2
 ring number 2
 connection plar opx 21
 caller-id enable
!
voice-port 0/1/3
 ring number 2
 connection plar opx 21
 caller-id enable
 !
 !
 !
 !
 --More--         !
mgcp behavior rsip-range tgcp-only
mgcp behavior comedia-role none
mgcp behavior comedia-check-media-src disable
mgcp behavior comedia-sdp-force disable
!
mgcp profile default
!
!
!
!
dial-peer voice 1 pots
 destination-pattern 9T
 port 0/0/0
!
dial-peer voice 1000 voip
 preference 2
 destination-pattern .
 session target ipv4:10.20.200.2
 codec g711ulaw
!
dial-peer voice 2 pots
 destination-pattern 8T
 port 0/1/0
!
dial-peer voice 3 pots
 destination-pattern 7T
 port 0/1/1
!
!
!
!
gatekeeper
 shutdown

Thanks

[Mohammed al Baqari · Accepted solution]

Hi,

As I thought this is caused by inter-digit timeout for matching variable length dialpeers (xT). The options you having are:

1. The ideal solution is to use destination-pattern as fix length such as (7.......$) instead of 7T (this is just example). However, this isn't always possible especially for international calls because you don't know where is the call going to.

2. The best solution is to introduce '#' for committing the calls such as 7T#. In this case, the users have to hit '#' to send the call immediately. You can have duplicate dialpeers for 7T and 7T# to give the users two options to wait for the call to go or hit '#' to send the call immediately.

3. Reduce T302 timer which is 15 sec by default. Usually I found 5 sec is quite good match between users dialing digits and users waiting for call to proceed.


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[ranjithkumarpullaikodi100]

i have also the same issue in FXo line getting delay 13-15 seconds