Integrating Cisco Unified Communications Manager and Video Communications Server

William Bell
Vice President, Solutions and Products


There are several methods that may be employed to integrate a CUCM cluster and a VCS cluster. These methods include H.323 trunks, SIP trunks, and configuring the CUCM to register to the VCS. This latter method is reserved for older versions of CUCM. In this article, we are going to assume VCS X6 or later and CUCM 6x/7x/8x.

The following diagram provides an overview of our example design:

In our example, we have a CUCM cluster that hosts voice gateways, VoWLAN phones, and standard desk phones. The voice gateways may be leveraged to provide media path for PSTN parties that are audio-only participants in a video call or conference. Desk phones may be standard voice phones or video enabled phones such as the 9951 or 9971 IP phone.

The CUCM cluster has at least one SIP trunk to the VCS call control cluster. The VCS itself hosts SIP and H.323 registrations from video endpoints and video infrastructure devices such as Multipoint Control Units (MCUs) and ISDN gateways.

Configuration Overview

For our example,

  • Assume we have a multi-node CUCM cluster with three (3) call processing nodes.
  • Assume we have a multi-node VCS cluster with two (2) VCS Control systems.
  • A 5-digit dial plan is used and (conveniently) we can add video to the dial plan without introducing overlap
  • There are two approaches that will be discussed:
    • Using static SIP trunks
    • Using DNS SRV for dynamic load balancing and failover

CUCM Configurations

There are several CUCM system level configurations that warrant some attention when preparing to integrate a CUCM and VCS solution. These are discussed in order of configurations.

Device Pools

While not required, it is a good idea to define a device pool specifically for the SIP trunks that are added for the VCS cluster. This gives administrative control over media resource group lists and region. Though, MRGLs can be added at a trunk level, I don’t typically adopt that practice.

SIP Trunk Security Profile

If you plan on leverage TLS and SRTP, then you need to have a security profile that enforces this configuration when applied to the VCS SIP trunk. In addition, you will also need to deal with security certificates, which are discussed later.

SIP Profile


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Nick Kelly

Cybersecurity Engineer, Cisco

Nick has over 20 years of experience in Security Operations and Security Sales. He is an avid student of cybersecurity and regularly engages with the Infosec community at events like BSides, RVASec, Derbycon and more. The son of an FBI forensics director, Nick holds a B.S. in Criminal Justice and is one of Cisco’s Fire Jumper Elite members. When he’s not working, he writes cyberpunk and punches aliens on his Playstation.


Virgilio “BONG” dela Cruz Jr.

CCDP, CCNA V, CCNP, Cisco IPS Express Security for AM/EE
Field Solutions Architect, Tech Data

Virgilio “Bong” has sixteen years of professional experience in IT industry from academe, technical and customer support, pre-sales, post sales, project management, training and enablement. He has worked in Cisco Technical Assistance Center (TAC) as a member of the WAN and LAN Switching team. Bong now works for Tech Data as the Field Solutions Architect with a focus on Cisco Security and holds a few Cisco certifications including Fire Jumper Elite.


John Cavanaugh

CCIE #1066, CCDE #20070002, CCAr
Chief Technology Officer, Practice Lead Security Services, NetCraftsmen

John is our CTO and the practice lead for a talented team of consultants focused on designing and delivering scalable and secure infrastructure solutions to customers across multiple industry verticals and technologies. Previously he has held several positions including Executive Director/Chief Architect for Global Network Services at JPMorgan Chase. In that capacity, he led a team managing network architecture and services.  Prior to his role at JPMorgan Chase, John was a Distinguished Engineer at Cisco working across a number of verticals including Higher Education, Finance, Retail, Government, and Health Care.

He is an expert in working with groups to identify business needs, and align technology strategies to enable business strategies, building in agility and scalability to allow for future changes. John is experienced in the architecture and design of highly available, secure, network infrastructure and data centers, and has worked on projects worldwide. He has worked in both the business and regulatory environments for the design and deployment of complex IT infrastructures.