MGCP Common Messages

by | Mar 4, 2010 | CUCM, IOS, MGCP, Non classé, Written Theory | 0 comments

Here are some MGCP messages that you can see in the interaction between the Call Agent and the endpoint:

  • EndpointConfiguration (EPCF) : A Call Agent sends this message to a gateway to specify signal encoding that will be received by an endpoint . A good example of these message will be the audio encoding using ulaw or alaw.

  • CreateConnection (CRCX) : This command creates a connection between 2 endpoints. the connection is created based on parameters included with the commad such as codec , allowable bandwidth, use of echo cancellation, silence suppression , gain control, and so on.

  • ModifyConnection (MDCX) : This is used to modify the parameters associated with a connection that was previously created.

  • DeleteConnection (DLCX) : The Call Agent can send this command to inform a gateway that it should terminate a connection, and a gateway can send this command to indicate that a connection can no longer be sutained. In response to a DeleteConnection, an endpoint sends statistics associated with the connection.

  • NotificationRequest (RQNT) : This is sent by the Call Agent to instruct a gateway to informit when specific events occur in an endpoint. Example : be on-hook/off-hook, tones,..

  • Notify (NTFY) : An endpoint uses this command to inform a Call Agent when requested events occur

  • AuditEndpoint (AUEP) : The Call Agent sends the AuditEndpoint command to the gateway to audit the status of an endpoint. The Call Agent can, for example, find out signal status, bearer information, …

  • AuditConnection (AUCX) : The Call Agent sends this command to the  gateway to find out the status of  a connection. Connection status information that can be retrieved using this command includes Call ID, Connection Mode, and connection parameters

  • RestartInProgress (RSIP) : The gateway sends this command to the Call Agent to inform the Call Agent that it is taking an endpoint or group of endpoints out of service or is returning an endpoint or group of endpoints to service.

Cisco Discovery Protocol – CDP : Quick Definition

by | Mar 3, 2010 | CUCM, Non classé, Written Theory | 0 comments

CDP is a Cisco proprietary protocol that was designed for neighbor discovery. It is a Layer 2 protocol that sends multicast advertisements using SNAP encapsulation. The advertisements are sent by default every 60 seconds, and there is a default hold time of 180 seconds.

CDP advertisements can contain information such as DeviceID, Address, PortID, Capabilities, Version, Platform and native VLAN with much information in ASCII format.

CTI Control Devices

by | Mar 3, 2010 | CUCM, Non classé, Written Theory | 0 comments

There are 3 different types of CTI Control devices:

  • CTI Ports : Virtual device with virtual lines
  • CTI Route Points : These can receive many calls simultaneously for application-controlled redirection
  • Cisco IP Phones : These are phones that a CTI application can control

CTI,TAPI and JTAPI

by | Mar 3, 2010 | CUCM, Non classé, Written Theory | 0 comments

Computer Telephony Interface/Integration (CTI) provides a connection between telephone systems and computers and allows them to take advantage of computer processing when managing phone calls.

Telephony Application Programming Interface (TAPI) which was developped originally by Microsoft, and Java Telephony Application Programming Interface (JTAPI) can interact with Call Manager using CTI Communication via the CTI Manager.

Cisco Unity Express (CUE) also communicates with Call Manager using JTAPI and with CTI Quick Buffer Encoding (CTI-QBE) protocol.

Call Manager uses port TCP/2748 and TCP/2789 for CTI/JTAPI Communications.

CTI Manager interfaces with applications and communicates with Call Manager via SDL (System Distribution Layer) so it relies on the Cisco Database Layer Monitor Service. CTI Manager operates separately from Call Manager, and it is possible to have more than one CTI Manager active across the cluster but ONLY ONE instance on any given server !

So a JTAPI or TAPI application can connect to several CTI Manager at the same time but can use only one of those connections at a time.

Attendant Console

by | Mar 3, 2010 | CUCM, Non classé, Written Theory | 0 comments

Attendant Console is an application which is interacting with the server application TCD ( Telephony Call Dispatcher) which will monitor the linestate of every devices.

Once this application installed and configured properly , the assistant is able to see the user line  and related informations.

IPMA

by | Mar 2, 2010 | CUCM, Non classé, Written Theory | 0 comments

IPMA is an application for managers and assistants which permits to assistants to handle managers’ calls. There are 2 types of IPMA operations:

  • Proxy-line support mode
  • Shared-line support mode

Proxy-line is available since Call Manager version 3.3. In this mode , calls made to managers are intercepted and redirected to an assistant or target based on the call rules. A manager in this mode can have only one associated assistant. Also the configuration of this mode is more complex as it requires the use of 2 CSS, 3 partitions, translation patterns and route points.

Shared-line is available since Call Manager version 4.0 and permits that managers and assistants share a primary line ( and DN associated). So in this mode , no special configuration is required and has also the advantage that a manager can have up to 10 assistants

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