MGCP as a gateway protocol with Cisco Unified Communications Manager

Media Gateway Control Protocol configuration was configured manually in much older versions of IOS. The manual configuration required extensive configuration that has been automated with IOS 12.2(2). Use the Cisco IOS Feature Navigator at www.cisco.com/go/fn to determine the exact version of IOS and feature set required to support the automatic ccm-manager config download feature. The automatic MGCP provisioning feature will automate the global MGCP configuration with the use of the following two commands: ccm-manager config ccm-manager config server 10.1.1.100 The ccm-manager config server command should point to the Cisco Unified Communications Manager (CUCM) server running the Cisco TFTP service. The TFTP server has an XML configuration file that the gateway router can request from Call Manager. The configuration file is then downloaded to the gateway router where a dynamic IOS configuration is loaded based on the Cisco Call Manager configuration. This assumes that the fully qualified domain name (FQDN) provisioned in Call Manager matches the hostname.domain-name configured on the router. A hostname of R1_2811 with a domain-name of globalknowledge.com would require a Call Manager MGCP gateway configuration of R1_2811.globalknowledge.com. Although different versions of Call Manager and IOS will generate slightly different configurations, the following global options are generated by the automatic download if a PRI is configured for voice-port 0/0/0 on CUCM. hostname R1_2811 ip domain-name globalknowledge.com isdn switch-type primary-ni voice-card 1 dspfarm dsp services dspfarm controller T1 0/0/0 framing esf linecode b8zs pri-group timeslots 1-23,24 service mgcp interface Serial0/0/0:23 no ip address isdn switch-type primary-ni isdn incoming-voice voice isdn bind-l3 ccm-manager no cdp enable ccm-manager fallback-mgcp ccm-manager mgcp ccm-manager music-on-hold ccm-manager config server 10.1.1.100 ccm-manager config ! mgcp call-agent 10.1.1.100 2427 service-type mgcp version 0.1 mgcp dtmf-relay voip codec all mode out-of-band mgcp rtp unreachable timeout 1000 action notify mgcp modem passthrough voip mode nse mgcp package-capability rtp-package mgcp package-capability sst-package no mgcp package-capability fxr-package mgcp package-capability pre-package no mgcp timer receive-rtcp mgcp sdp simple mgcp fax t38 inhibit mgcp rtp payload-type g726r16 static ! mgcp profile default The primary difference between H.323, SIP, and MGCP is ownership of the dial plan and IOS configuration complexity. SIP and H.323 require a high IOS competency level, while MGCP does not. Once the MGCP gateway is communicating with CUCM, all device configurations are done from CUCM. If a show voice port summary display output verified there was an FXO analog interface in voice-port 0/1/0, endpoint 0/1/0 could be configured in CUCM. The configuration would result in the following addition to the routers running IOS configuration: Dial-peer voice 200001 pots Service mgcpapp Port 0/1/0 This dial-peer instructs the router to pass the call to the MGCP call agent (CUCM). Call agent is language that’s very specific to the Internet Engineering Task Force (IETF) MGCP standard. The MGCP endpoint is not very intelligent. The MGCP protocol has a master/slave model where the call agent is the master and the gateway interface (MGCP endpoint) is the slave. Cisco’s proprietary Skinny Client Control Protocol (SCCP) follows this model in many ways. The next blog post will cover SCCP as a gateway protocol. More coverage of gateway protocols can be found in the Cisco Press book, Implementing Cisco Unified Communications, Part 1 (CIPT1).

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