How to Route outgoing calls through specific ISDN channels in E1/T1?

[Muthurani Lavanya Paneerselvam]

• Introduction
• Problem Description
• Solution
• Related Information

Introduction

This document covers the configuration procedures on how to route outgoing calls to PSTN Operator through ISDN using Specific Channels/timeslots in E1/T1.

Problem Description

Sometimes the Public Switched Telephone Network (PSTN) Telco wants the outgoing calls from VOIP network to be routed only through Specific ISDN Channels/timeslots in E1/T1.

Requirement/ Issue: When Extension 1002 makes outbound call, Call should go out through First 1-10 channels and when Extension 1003 makes call, channels 11-14 should be used. 1002 should not be able to use channels 11-14.

Sample Outgoing Call flow from VOIP Network to PSTN Network

Solution

Here is the solution with the configuration commands to route the outbound calls from VOIP Network to PSTN Operator through Specific ISDN Channels in E1/T1.

Sample Configuration

Restriction of outbound calls through Specific ISDN channels in E1/T1 is implemented using Dial-Peer Class of Restriction (COR) command in Cisco IOS gateway.

Following command needs to be issued on the Gateway:

controller E1 0/1/0

trunk-group first timeslots 1-10
trunk-group sec timeslots 11-14

!

dial-peer cor custom
name 1002
name 1003

! --- Configure dial-peer cor custom and assign a meaningful name that specifies the way CORs (Class Of Restriction) apply to dial-peers

!
dial-peer cor list 1002
member 1002

! --- Create the actual lists of the restrictions that apply to the dial-peer

!
dial-peer cor list 1003
member 1003

!
dial-peer voice 2000 pots
trunkgroup sec
corlist outgoing 1002
destination-pattern 2...
forward-digits all

! --- Create POTS dial-peer and specify the COR list to be used for outbound call

!
dial-peer voice 1002 voip
corlist incoming 1002
answer-address 1002

! --- Create VOIP dial-peer and specify the COR list to be used

!
dial-peer voice 1003 voip
corlist incoming 1003
answer-address 1003

! --- Create VOIP dial-peer and specify the COR list to be used

!
dial-peer voice 2222 pots
trunkgroup first
corlist outgoing 1003
destination-pattern 2...
forward-digits all

! --- Create POTS dial-peer and specify the COR list to be used for outbound call

!

Related Information

• Configuring Class Of Restrictions (COR)
• Blog:PRI Trunkgroup Hunting Behaviour
• Troubleshooting and Debugging VOIP Call basics

[dolphine55]

Thanks for sharing it's a very good idea !

[Muthurani Lavanya Paneerselvam]

Thank you Tina.

[juankcs85]

Hi

it's necessary somethis additional? i have a 2900 series router and this commands does not exist

[maheshgunaratne]

Hi,

I'm using E1 on 2921 router for external calls from CUCM.

I need to route external calls from one internal ext.(3488) via only specific channel.(channel-18)

Reason to do that is telco will assign the caller ID for external call base on Line circuit as in their config.

Thanks.

[Yuen]

thanks a lot very helpful help me resolve a big problem. ^_^