Introduction
Starting IOS version 15.1(2)T, we can match inbound dial-peers via IP Address or hostname. This enables CUBE/TDM-SIP to connect to two or more different ITSPs allowing specific call routing, codec selection, digit manipulation, CAC, QoS, or security policies for each ITSP.
Feature Overview
Dial-peer selection is based on immediate SIP neighbor's address information and applicable only to incoming SIP calls. The address information is retrieved from the VIA header of the incoming message, which is then used to lookup the dial-peer that has the best match for the criteria selected. The lookup will first attempt to match a dial-peer with the address information in the following order:
- Via header
- Request URI
- To URI
- From URI
- Called Number
If none of the parameters match, then the default inbound dial-peer is matched.
This feature also allows for Generic DNS Caching framework for faster FQDN to IP Address lookup. For a configured FQDN, the DNS Caching framework resolves the FQDN and stores the corresponding set of IP addresses for it. The framework also takes care of the regular DNS refreshes for the FQDN. For a dial-peer match to be done, if the incoming Via header has an IP address and the configuration has an FQDN, then the corresponding resolved addressed of this FQDN is queried from the DNS Caching Framework.
Call Flow
ITSP1 ---> SIP --> Call from source address 172.16.1.10 ----->
| ----> CUBE - SIP - CUCM - IP Phones
ITSP2 ---> SIP --> Call from source address 172.31.10.10 --->
Sample Config
!To handle incoming calls from ITSP1
voice class uri 1001 sip
host ipv4:172.16.1.10
dial-peer voice 1 voip
description Calls from ITSP1
session protocol sipv2
incoming uri via 1001
max-connection 10
codec g711ulaw
acc-qos controlled-load
req-qos controlled-load
!To handle incoming calls from ITSP2
voice class uri 1002 sip
host ipv4:172.31.10.10
dial-peer voice 1 voip
description Calls from ITSP1
incoming uri via 1002
session protocol sipv2
max-connection 30
codec g729r8
