January 2017 · Estimated reading time: 10 minutes
The Evolution of Unified Communications
By 2017, enterprises were rapidly adopting Unified Communications (UC) as a means of improving internal collaboration, enhancing remote work capabilities, and consolidating disparate communication systems into a unified experience. UC systems combine voice, video, messaging, conferencing, and mobility into a single framework that supports modern business needs. Cisco, as a market leader, offered an enterprise-grade solution with its Unified Communications Manager (CUCM), Jabber, and TelePresence platforms.
The challenge for most enterprises was not whether to adopt UC, but how to deploy it without disrupting operations or creating new complexities. Unlike traditional voice systems, UC integrates tightly with IT infrastructure, including routing, switching, identity services, and endpoint security.
Why Cisco UC?
Cisco's ecosystem offered deep integration across voice, video, presence, instant messaging, and mobility. CUCM became a de facto standard in large environments. It supported advanced features like SIP trunking, inter-cluster lookup services (ILS), extension mobility, and native call queuing. The ability to pair with Cisco Expressway, ISR routers with CUBE, and a vast array of certified endpoints made Cisco UC a future-proof investment for many enterprises.
Pre-Rollout Considerations
UC planning requires more than simply installing CUCM. It starts with a network readiness assessment. Key factors include:
- QoS Configuration: Proper classification, marking, queuing, and policing for voice and video traffic.
- WAN Capacity: Ensuring sufficient bandwidth for branch offices using G.711, G.729, or video codecs.
- Switch Readiness: PoE capabilities, LLDP-MED support, and VLAN segmentation.
- IP Addressing: Static or DHCP-based schemes with clear management scopes.
- Clock and Sync: Reliable NTP sources and redundant clocking for voice gateways.
Neglecting these areas typically leads to poor user experiences — dropped calls, jitter, registration issues, or failed call routing.
Designing the UC Architecture
A properly designed Cisco UC rollout typically includes the following elements:
- CUCM Cluster: Publisher, TFTP, and multiple subscribers (with redundancy).
- Unity Connection: Voicemail integration and speech-enabled directory services.
- IM & Presence (IMP): Integration with Cisco Jabber for chat and presence.
- Expressway Core and Edge: Secure mobile and remote access (MRA).
- Gateways: Voice gateways for PSTN and SIP trunk interconnects (ISR or CUBE).
- Certificates: CA-signed certs for secure signaling and HTTPS services.
High availability and geographic redundancy are common in multi-site deployments. Centralized call processing reduces operational complexity but requires a resilient WAN and SRST fallback.
Endpoint Selection and Configuration
Enterprises must also standardize endpoints. Cisco IP phones (8800 series, 7800 series), video endpoints (DX80, Room Kit), and softphones like Jabber need consistent provisioning. DHCP options 150 and 66, XML configuration files, and auto-registration processes help reduce the workload.
For mobile users, Jabber offers desktop, iOS, and Android clients. When integrated with Expressway, Jabber supports full VoIP and video functionality over the internet without a VPN — a key capability for remote workforces and BYOD policies.
Directory and Identity Integration
CUCM supports LDAP integration for directory lookup and synchronization. Active Directory is the most common source. Attributes like telephoneNumber, mail, and department are synchronized. User authentication can be done against AD or locally. Single sign-on (SSO) via SAML has become standard practice in large enterprises.
Directory integration is also critical for Jabber clients, which rely on presence and contact resolution across the organization. Consistent directory hygiene becomes a foundational UC success factor.
Security and Policy Management
Security is often overlooked during UC deployments. Key areas to address:
- SIP and SRTP: Encrypting signaling and media streams.
- Firewall Pinholes: Ensuring secure traversal for MRA (via Expressway).
- Device Authentication: Using certificates and secure provisioning.
- Access Control: Role-based access within CUCM and Unity.
Cisco’s Security by Default (SbD) features help mitigate threats, but ongoing monitoring and change control are essential. Deploying UC in a PCI or HIPAA environment requires even more stringent controls and call logging.
Migration Strategies
Most enterprises transition to Cisco UC from legacy PBXs or hybrid environments. The migration strategy depends on coexistence needs:
- Phased Migration: Departments are migrated over time using inter-PBX trunks.
- Greenfield: A fresh deployment with full cutover and number porting.
- Hybrid: Integration with existing systems for voicemail or fax.
Testing, pilot groups, and detailed porting timelines must be defined. Help desk teams require updated call flows, hunt group behavior, and escalation paths.
Lessons Learned
Real-world rollouts often uncover gaps. Common pain points include:
- Overlooking endpoint firmware updates.
- Failing to validate QoS end-to-end (switch to WAN).
- Inadequate Expressway licensing or certificate issues.
- Misconfigured dial plans and overlapping extensions.
Successful UC projects depend not only on solid infrastructure but also on strong project management, cross-team collaboration, and end-user training. Documentation and knowledge transfer ensure operational success post-implementation.