Huawei U-SYS MRS6100 Technical Manual page 29

Technical Manual
U-SYS MRS6100 Media Resource Server
Figure 5-3 Relations among endpoints, connections, calls, and gateways
When the two gateways are managed by the same CA, the connection can be set up
through the following steps:
1) The CA asks the first gateway to create a connection on the first endpoint. The
gateway allocates resources to that connection and responds to the command
through a session description. The session description contains the information
necessary for a third party to send the packets to the connection, such as IP
address, UDP port, and packing parameters.
2) The CA then asks the second gateway to create a connection on the second
endpoint. The command carries the session description provided by the first
gateway. The gateway allocates resources to this connection and responds to
the command through a session description.
3) The CA provides the second session description to the first endpoint by using the
command for modifying connections. Once this process is complete, the two
endpoints can communicate with each other.
VI. Connection identifier
The gateway creates the connection. It assigns a unique identifier for the connection
on the local end. The connection identifier is a hexadecimal character string.
VII. Call identifier
Calls are identified by unique identifiers. The identifiers are created by the MGC. Call
identifiers can be considered as unstructured character strings. When an MGC builds
several connections for the same call, the connections must be associated with the
same call.
VIII. Naming CA and other entities
In the MGCP, the CAs are identified by domain names. To enhance the system
reliability, the MGCP can have a redundant CA. These CAs share the same domain
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5-4
Chapter 5 MGCP and SIP