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Lab 2-1: Key Features of Cisco Unified Communications Solutions

Q&A

1. The audio streams between two IP Phones must go through the Call Agent (CUCME or CUCM Cluster)

    • False. In a typical Cisco IP telephony deployment, the Call Agent (CUCME or CUCM) handles call signaling (setup, teardown, features, etc.), but once the call is established the RTP audio streams flow directly between the two IP phones (peer‑to‑peer). The Call Agent only stays in the signaling path; it does not carry the media—unless you specifically deploy a media resource (transcoder, conference bridge, SRST, etc.) that forces the media through a server.

2. After registering, an IP Phone can make and receive calls, even if the Call Agent (CUCME or CUCM Cluster) is down

    • False. Once an IP Phone registers with CUCM or CUCME, that Call Agent still controls all call‑signaling (dial plan, call setup/teardown, feature invocation, etc.). If the Call Agent goes offline and you have not deployed Survivable Remote Site Telephony (SRST) on a router, the phones lose their signaling path and cannot place or receive new calls. Only when SRST is configured will phones fail over to a local router and continue to make/receive calls during a CUCM/CUCME outage.

3. Explain why, in a larger environment, IP Phones do not typically receive call processing from the CUCM Publisher

    • In smaller environments (500 IP Phones or less), it's perfectly fine to use the Publisher for call processing and database management. However, once you exceed that number, it's generally a best practice to pull the Publisher out of call processing and leave that work to the Subscribers. Likewise, once you exceed 1250 users, Cisco recommends moving the TFTP server role to a dedicated server.
Key features of Cisco Unified Communications Manager (CUCM)

1. Full support for audio and video telephony: The core feature provided by CUCM. In the same way CUCME acts as the director of a small organization, CUCM supports audio and video calls for midsize to enterprise class corporations.

2. Appliance-based operation: Modern CUCM versions run as an appliance, which means the underlying operating system is hardened (secured) and inaccessible.

3. Redundant server cluster: CUCM supports redundant servers configured in a cluster relationship. The clustering capabilities replicate both database information (containing static data such as directory numbers and route plans) and real-time information (containing dynamic data, such as active calls). CUCM clusters can scale up to 30.000 IP phones (SCCP or SIP in unsecure mode) or 27.000 IP phones (SCCP or SIP in secure mode).

4. Intercluster and voice gateway control and communication: Even though a CUCM cluster has a limit of 30.000 IP phones, you can create as many clusters as you like (with up to 30.000 IP phones each) and connect them together using intercluster trunk connections. In addition to using Intercluster trunk links to call outside your own cluster, CUCM can also connect to voice gateways (such as a Cisco router), which can connect to various other voice networks (such as the PSTN or legacy PBX systems).

5. Built-in Disaster Recovery System (DRS): As a built-in feature, the CUCM DRS service allows you to back up the CUCM database (and any additional files you'd prefer) to a network device or over Secure FTP (SFTP).

6. VMware Virtualization Support: CUCM 8.0 is supported in a VMware ESXi environment. This bring all the high availability and scalability benefits of virtualization to your CUCM deployment.

7. Directory service support or integration: VoIP networks can use network user accounts for a variety of purposes (phone control, attendant console control, and so on). CUCM has the capability to be its own directory server to hold user accounts or it can integrate into an existing corporate directory structure (such as Microsoft Active Directory) and pull user account information from there.

Key features of Cisco Unity Connection

1. Proven appliance-based platform: Cisco Unity Connection is built on top of the same stable, hardened, appliance-based operating system as CUCM. (These two software products even use the same installation DVD).

2. Up to 20.000 mailboxes per server: It scales to a massive size per server. Even though Unity Connection supports a single-server configuration, most organizations will opt for a high availability pair of servers.

3. Access voicemails from anywhere: Allows voicemail retrieval from phone, email, web browser, mobile devices, and instant-messenger platforms.

4. LDAP directory server integration: Similar to CUCM, Cisco Unity Connection can integrate with an existing corporate directory (such as AD) to avoid creating a duplicate user database.

5. Microsoft Exchange support: Cisco Unity Connection can integrate with an existing Microsoft Exchange deployment to enable features such as different call treatment based on you Exchange calendar, email text-to-speech (hear your emails read to you from a phone), manage Exchange calendar RSVPs from a phone, and so on.

6. Voice Profile for Internet Mail (VPIM) support: VPIM is a standard allowing voicemail servers to integrate together to exchanging voicemails (and other messaging).

7. Active/Active high availability: Cisco Unity Connection used a Publisher/Subscriber IBM Informix database scheme just like CUCM between a pair of servers. The pair of servers can support up to 20.000 mailboxes in a redundant fashion. Both servers can accept client requests (giving it the active/active redundancy). Typically, the largest Cisco Unity Connection server can support up to 250 voicemail ports (essentially allowing 250 people to check their voicemail at a time). By creating a high availability pair, you can now support 500 voicemail ports.

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