Troubleshooting Guide for Cisco CallManager, Release 3.1(1)

Table Of Contents


ITU-T companding standard used in the conversion between analog and digital signals in PCM systems. A-law is used primarily in European telephone networks and is similar to the North American µ-law standard.
Admission Confirm.
Answer Number Indication. The calling number (number of the calling party).
Admission Request.

Bearer channel. In ISDN, a full-duplex, 64-kbps channel used to send user data.

Calling Search Space
The Calling Search Space defines what directory numbers and route patterns a given device can call. It is a grouping of partitions to look through when making a call. For example, assume there are several Partitions in a Calling Search Space named Executive. If a Cisco IP Phone number is in the Executive Calling Search Space, then when initiating a call, it looks for the example NYInternationalCall, NYLongDistance, NYLocalCall, and NY911 Partitions available to search through. A Cisco IP Phone number that has a Guest Calling Search Space, for example, might only be allowed to search through NYLocalCall and NY911 Partitions, so that if the user tries to dial an international number, it will not find a match and the call cannot be routed.
Call Control API. Used by Cisco IOS to handle VoIP call processing.
Cisco Connection Online ( Provides the latest information on Cisco products, technical support information, and technical documentation.
Call Detail Record. Information about call origination, destination, and duration, used to create billing records.
Cisco IOS
Cisco system software that provides common functionality, scalability, and security for all products under the CiscoFusion architecture. Cisco IOS allows centralized, integrated, and automated installation and management of internetworks, while ensuring support for a wide variety of protocols, media, services, and platforms.
Cisco CallManager cluster. A logical grouping of several Cisco CallManager servers.
Call Management Records, also known as Diagnostic CDRs. Records that contain the count of bytes sent, packets sent, jitter, latency, dropped packets, and so on.
Coder-Decoder. A DSP software algorithm used to compress/decompress speech or audio signals.
Configuration file used by devices.

Data channel. Full-duplex, 16-kbps (BRI) or 64-kbps (PRI) ISDN channel. Used for signaling and control.
Disengage Confirm.
Dynamic Host Configuration Protocol. Provides a mechanism for allocating IP addresses dynamically so that addresses can be reused when hosts no longer need them.
Directory Number. This is the phone number of an end device. It can be a number assigned to a Cisco IP Phone, a Cisco IP SoftPhone, fax machine, or analog phone attached to a gateway. Examples include 1000 and 24231.
Dialed Number Identification Service.
Domain Name System. System used in the Internet for translating names of network nodes into addresses.
Disengage Request.
Dual tone multifrequency. Use of two simultaneous voice-band tones for dialing (such as touch tone).

Stream of data traveling between two endpoints across a network (for example, from one LAN station to another). Multiple flows can be transmitted on a single circuit.
Full duplex
Capability for simultaneous data transmission from both a sending station and a receiving station.

Describes the 64-kbps PCM voice coding technique. In G.711, encoded voice is already in the correct format for digital voice delivery in the PSTN or through PBXs. Described in the ITU-T standard in its G-series recommendations.
Describes CELP compression where voice is coded into 8-kbps streams. There are two variations of this standard (G.729 and G.729 Annex A) that differ mainly in computational complexity; both provide speech quality similar to 32-kbps ADPCM. Described in the ITU-T standard in its G-series recommendations.
A gateway allows H.323 terminals to communicate with non-H.323 terminals by converting protocols. A gateway is the point at which a circuit-switched call is encoded and repackaged into IP packets.

An ITU standard that governs H.225 session establishment and packetization. H.225 actually describes several different protocols: RAS, use of Q.931, and use of RTP.
An ITU standard that governs H.245 endpoint control.
Extension of ITU-T standard H.320 that enables videoconferencing over LANs and other packet-switched networks, as well as video over the Internet.
Half Duplex
Capability for data transmission in only one direction at a time between a sending station and a receiving station. BSC is an example of a half-duplex protocol.
Short on-hook period usually generated by a telephone-like device during a call to indicate that the telephone is attempting to perform a dial-tone recall from a PBX. Hookflash is often used to perform call transfer.

Intra-Cluster Control Protocol.
Integrated Services Digital Network. Communication protocol, offered by telephone companies, that permits telephone networks to carry data, voice, and other source traffic.

The variation in the arrival times of voice packets.

Kilobits per second.
Keepalive Message
A notice sent by one network device to another that the virtual circuit (VC) between the two is still active.

Line Side
A circuit from a subscriber's telephone to an end office (EO) or central office (CO).
Logical Connection
A call that makes a physical connection to a network, establishes communication with another device on the network, and remains connected until the user initiates a disconnect request.
Loop Back
A method of performing transmission tests on a circuit that does not require the assistance of personnel at the far end.

MAC Address
Media Access Control. A standardized data link layer address that is required for every port or device that connects to a LAN. Other devices in the netowkr use thes addresses to locate specific ports in the network and to create and update routing tables and data structures. Also called a physical address.
Media Gateway Control Protocol. A protocol for Cisco CallManager to control VoIP gateways (MGCP endpoints).
Media Termination Point. A virtual device that allows transfer, forward, conference, and hold features on any G.711µ-law call between an IP phone and any H.323 gateway, gatekeeper, or client. A call using MTP will automatically convert A-law to µ-law (and vice versa), if required.

North American Numbering Plan.
Network Address
Network layer address referring to a logical, rather than a physical, network device. Also called a protocol address.

A Partition is a logical grouping of Directory Numbers and Route Patterns with similar reachability characteristics. For simplicity, these are usually named for their characteristic, such as NYLongDistance or NY911. When a DN or Route Pattern is placed into a certain partition, this creates a rule for who can call that device or Route List.
Private Branch Exchange. Digital or analog telephone switchboard located on the subscriber premises and used to connect private and public telephone networks.
Primary Rate Interface. Primary rate access consists of a single 64-Kbps D channel plus 23 (T1) or 30 (E1) B channels for voice or data.
Public Switched Telephone Network. General term referring to the variety of telephone networks and services in place worldwide.

An ITU standard that describes ISDN signaling. The H.225.0 standard uses a variant of Q.931 to establish and disconnect H.323 sessions.

Registration, Admission, and Status protocol. Protocol used in the H.323 protocol suite for discovering and interacting with a gatekeeper.
Route Filter
A route filter can be used not only to restrict dialing, but also to identify a subset of a wildcard pattern (when using the @ wildcard in the North American Dialing Plan). For example, it could be used to block the dialing of 900 area codes. In can also be used in conjunction with Partitions and Calling Search Spaces to set up complex rules. For example, assume you have three user groups established, Executive, Staff, and Guest. A Route Filter can allow the Executive user group to dial international numbers; while the Staff user group can only dial local numbers or long distance calls; and the Guest user group can only dial local numbers, 911, and 800 numbers.
Route Group
A Route Group is a list of one or more gateways or ports on gateways that are seen as equal access. It is analogous to a trunk group in traditional PBX terminology. For instance, you may have two PRI circuits to the same carrier that can be used arbitrarily. A gateway (or a particular port on a gateway) can only be added to one Route Group.
Route List
Formerly called Route Point, the Route List allows Cisco CallManager to hunt through a list of Route Groups in a configured order of preference. Multiple Route Lists can point to the same Route Groups.
Route Pattern
A specific number or, more commonly, a range of dialed numbers that will be used to route calls to a device (such as a Cisco Access DT-24+ Gateway or a voice-capable router) or indirectly via a Route List. For example, 1XXX signifies 1000 through 1999. The X in 1XXX signifies a single digit, a wildcard. There are other wildcards (such as @, .,!). A Route Pattern does not have to be unique within a partition as long as the Route Filter is different.
Registration Reject.
Real-Time Transport Protocol. One of the IPv6 protocols. RTP is designed to provide end-to-end network transport functions for applications transmitting real-time data, such as audio, video, or simulation data, over Multicast or Unicast network services. RTP provides services such as payload type identification, sequence numbering, time stamping, and delivery monitoring to real-time applications.

Silence Suppression (Voice Activation Detection)
Silence Suppression allows a Cisco IP Phone to detect the absence of audio and does not transmit packets over the network. The sound quality may be slightly degraded but the connection may also use less bandwidth. Silence Suppression is disabled by default.
Simple Network Management Protocol. Network management protocol used almost exclusively in TCP/IP networks. SNMP provides a means to monitor and control network devices, and to manage configurations, statistics collection, performance, and security.
Structured Query Language. International standard language for defining and accessing relational databases.

T1 is a digital WAN carrier facility, transmitting DS-1-formatted data at 1.544 Mbps through the telephone-switching network, using AMI or B8ZS coding. CAS is a Channel Associated Signaling interface.
T1 is a digital WAN carrier facility, transmitting DS-1-formatted data at 1.544 Mbps through the telephone-switching network, using AMI or B8ZS coding. PRI is Primary Rate Interface. Primary rate access consists of a single 64-Kbps D channel plus 23 (T1) or 30 (E1) B channels for voice or data.
Transmission Control Protocol. Connection-oriented transport layer protocol that provides reliable full-duplex data transmission. TCP is part of the TCP/IP protocol stack.
Trivial File Transfer Protocol. Simplified version of FTP that allows files to be transferred from one computer to another over a network.
Translation Pattern
Used to translate called (DNIS) and calling (ANI) numbers before routing the call. For example, a call may come in to a set of numbers 919 392-3XXX that need to be translated to a set of Cisco IP Phones that are in the range of 2XXX. Cisco CallManager has a Translation Pattern set up for 919 392-3XXX. This pattern translates the leading 919 392-3 simply to 2 while leaving the remaining digits intact. Then the call is routed to the appropriate Cisco IP Phone. Translation Patterns are used only for true translations and should not be used for simple digit stripping and prefixing.

Companding technique commonly used in North America. µ-law is standardized as a 64-kbps codec in ITU-T G.711
User Datagram Protocol. Connectionless transport layer protocol in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery, requiring that error processing and retransmission be handled by other protocols. UDP is defined in RFC 768.

Voice Activation Detection (Silence Suppression)
Voice Activation Detection allows a Cisco IP Phone to detect the absence of audio and does not transmit packets over the network. The sound quality may be slightly degraded but the connection may also use less bandwidth. VAD/Silence Suppression is disabled by default.
Voice over IP.
Virtual LAN. Group of devices on one or more LANs that are configured (using management software) so that they can communicate as if they were attached to the same wire, when in fact they are located on a number of different LAN segments. Because VLANs are based on logical instead of physical connections, they are extremely flexible.