Overview of the Cisco Unified IP Conference Station 7936
The Cisco Unified IP Conference Station 7936 is an IP-based, hands-free conference station that uses Voice over IP (VoIP) technology. The Cisco Unified IP Conference Station replaces a traditional analog conferencing unit by providing business conferencing features, such as Call Hold, Call Resume, Call Transfer, Call Release, Call Pickup, Group Pickup, Redial, Mute, and Conference, over an IP network. Support for G.711 and G.729a audio compression is included.
The IP Conference Station works with several other key Cisco IP Telephony components, including Cisco Unified CallManager. The versions of Cisco Unified CallManager supported with the Cisco Unified IP Conference Station 7936 are 5.0, 4.2(1), 4.1(3), 4.0(1) and 3.3(5).
The following topics in this chapter provide information about the IP Conference Station and its interaction with other key components of the VoIP network.
The IP Conference Station supports several industry-standard and Cisco networking protocols required for voice communication. Table 1-1 lists the supported networking protocols and a brief overview of each.
Table 1-1 Supported Networking Protocols
Cisco Discovery Protocol (CDP)
CDP is a device-discovery protocol that runs on all Cisco-manufactured equipment.
Using CDP, a device can advertise its existence to other devices and receive information about other devices in the network.
The IP Conference Station uses CDP to communicate configuration information to the Cisco Catalyst switch. With CDP, each device sends periodic messages to a multicast address and in turn listens to the periodic messages sent by other devices. This allows devices on the network to discover one another and learn information such as protocols used, protocol addresses, and so on.
Dynamic Host Configuration Protocol (DHCP)
DHCP dynamically allocates and assigns an IP address to network devices.
DHCP enables you to connect the IP phone into the network and become operational without manually assigning an IP address and configuring additional required network parameters.
DHCP is enabled by default. If disabled, you must manually configure the IP address, subnet mask, gateway, and TFTP server on each station.
Internet Protocol (IP)
IP is a messaging protocol that addresses and sends packets across the network.
To communicate using IP, network devices must have an assigned IP address, subnet, and gateway.
IP addresses, subnets, and gateways identifications are automatically assigned if you are using the IP Conference Station with DHCP. If you are not using DHCP, you must manually assign these properties to each station locally.
Real-Time Transport (RTP)
RTP is a standard for transporting real-time data, such as interactive voice and video over data networks.
The IP Conference Station can collect and process RTP traffic from routers, hubs, and switches.
Skinny Client Control Protocol (SCCP)
Skinny Client Control Protocol. A Cisco protocol using low- bandwidth messages that allows communication between IP devices and the Cisco Unified CallManager.
The IP Conference Station uses SCCP to communicate with the Cisco Unified CallManager.
Transmission Control Protocol (TCP)
TCP is a a connection-oriented transport protocol.
The IP Conference Station uses TCP to connect to Cisco Unified CallManager.
Trivial File Transfer Protocol (TFTP)
TFTP allows you to transfer files over the network.
On the IP Conference Station, TFTP enables you to obtain a configuration file specific to the IP Conference Station type.
TFTP requires a TFTP server in your network, which can be automatically identified from the DHCP server. If more than one TFTP server is running in your network, you must manually assign a TFTP server to each station locally.
User Datagram Protocol (UDP)
UDP is a connectionless messaging protocol for delivery of data packets.
The IP Conference Station receives and processes UDP messages.
Voice over IP (VoIP)
VoIP enables you to transfer voice communications over a data network using the Internet Protocol.
The IP Conference Station connects to the PSTN through a VoIP gateway.
The Cisco Unified IP Conference Station functions much like the traditional analog conferencing unit allowing you to set up and place conference calls and receive calls. The Cisco Unified IP Conference Station also supports features such as call hold, redial, mute, call resume, call transfer and call release.
In addition to these traditional telephony features, the Cisco Unified IP Conference Station also includes features enabling you to administer and monitor it as an IP networking device. On the Cisco Unified IP Conference Station, you can locally configure features such as DHCP, TFTP, and IP settings.You can also integrate the Cisco Unified IP Conference Station with the corporate Lightweight Directory Access Protocol 3 (LDAP3) standard directory to enable users to search for co-workers’ contact information directly from the Cisco Unified IP Conference Station. From Cisco Unified CallManager, you can modify additional settings, which are viewable from the Cisco Unified IP Conference Station’s network configuration settings. Use this guide for information about configuring these settings.
The Cisco Unified IP Conference Station includes the following connections for accessing the data network and providing power to the station:
Power Interface Module (PIM) for connection between the Cisco Unified IP Conference Station and the network.
A single RJ-45 connector for accessing the data network and connecting to the PIM, which provides power to the Cisco Unified IP Conference Station.
Universal power supply for connection to a standard electrical power outlet in the wall.
Understanding Interactions with Other Cisco Unified IP Telephony Products
To function in the IP telephony network, the Cisco Unified IP Conference Station must be connected to a networking device, such as a Cisco Catalyst switch, in order to obtain network connectivity. The Cisco Unified IP Conference Station must also be registered with a Cisco Unified CallManager system in order to make and receive calls.
Understanding How the Cisco Unified IP Conference Station 7936 Interacts with Cisco Unified CallManager
Cisco Unified CallManager is a scalable, distributable and highly available enterprise IP telephony call processing system. Cisco Unified CallManager software runs on a Windows 2000 server and sets up and tears down calls between phones, integrating traditional PBX functionality with the corporate IP network. Cisco Unified CallManager manages the components of the IP telephony system, the conference stations, the phones, access gateways, and the resources necessary for such features as call conferencing and route planning.
For information about configuring Cisco Unified CallManager to work with the IP devices described in this chapter, refer to the Cisco Unified CallManager Administration Guide and the Cisco Unified CallManager System Guide.
Understanding the Startup Process
When connecting to the VoIP network, the Cisco Unified IP Conference Station goes through a standard startup process. Table 1-2 describes the startup process.
Table 1-2 Cisco Unified IP Conference Station 7936 Startup Process
Startup Process Step
1. Loading the Stored Station Image
The Cisco Unified IP Conference Station has non-volatile Flash memory in which it stores firmware images and user-defined preferences. At startup, the Cisco Unified IP Conference Station runs a bootstrap loader that loads a station image stored in Flash memory. Using this image, the station initializes its software and hardware.
2. Configuring VLAN
If the Cisco Unified IP Conference Station is connected to a Cisco Catalyst switch, the switch next informs the conference station of the voice virtual local area network (VLAN) defined on the switch. The Cisco Unified IP Conference Station needs to know its VLAN membership before it can proceed with the Dynamic Host Configuration Protocol (DHCP) request for an IP address.
3. Obtaining an IP Address
If the Cisco Unified IP Conference Station is using DHCP to obtain an IP address, the station queries the DHCP server to obtain one.
4. Accessing TFTP Server
In addition to assigning an IP address, the DHCP server also points the Cisco Unified IP Conference Station to a TFTP server. You must configure option 150 on the DHCP server for the TFTP information to be passed from the server to the client.
If the Cisco Unified IP Conference Station has a statically-defined IP address, you must manually configure the IP address of an alternate TFTP server; the Cisco Unified IP Conference Station uses this alternate TFTP server to receive its information.
5. Requesting the Configuration File
Configuration files (.cnf file format) for each telephony device, which define connection parameters for Cisco Unified CallManager, are stored on the TFTP server.
If you have enabled auto-registration in Cisco Unified CallManager, the Cisco Unified IP Conference Stations access a default configuration file (XMLDefault.cnf.xml) from the TFTP server. If you have manually entered the Cisco Unified IP Conference Stations into the Cisco Unified CallManager database, each station accesses an.xml file corresponding to its device name.
6. Contacting Cisco Unified CallManager
The configuration file defines how the Cisco Unified IP Conference Station communicates with Cisco Unified CallManager. After obtaining the file from the TFTP server, the station next attempts to make a TCP connection to the highest-priority Cisco Unified CallManager on the list.
The Cisco Unified IP Conference Station supports a sampling rate of up to 60ms. However, configuring the sampling rate above 30ms may result in voice quality degradation. For details, see the Cisco IP Telephony Solution Reference Network Design (SRND) for Cisco Unified CallManager 4.0 and 4.1 at the following URL; http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_implementation_design_guide_chapter09186a0080447513.html#wp1043960
Installation and Set-up Requirements for the Cisco Unified IP Conference Station 7936
To install and configure the Cisco Unified IP Conference Station, you must configure some network settings, set up Cisco Unified CallManager, and manually configure changes on the Cisco Unified IP Conference Station.
Table 1-3 provides information about these procedures.
Table 1-3 Installation and Set-up Requirements for the Cisco Unified IP Conference Station
For More Information
1. Configure routers, gateways, and switches to handle voice communication
Sets up the IP telephony network.
See the documentation included with these devices.
2. Configure Cisco Unified CallManager
Supports call processing and handling in the network.
See the Cisco Unified CallManager documentation or online help in the Cisco Unified CallManager application.
3. Decide whether to use auto-registration for your Cisco Unified IP Conference Stations or manually add them to the Cisco Unified CallManager database
Determines how the Cisco Unified IP Conference Station is added to the Cisco Unified CallManager database and how a directory number is assigned.