The TID format determines how various user terminal IDs on the MG interface are generated.

Prerequisites
NOTICE:
The configuration of the TID format is relatively complicated. The information such as the syntax rules with which the terminal prefix must comply and the requirements for the character string of the TID template is defined in the protocol, and is not described here. This topic describes only some basic information. It is recommended that you refer to the TID description in ITU-T H248.1 (applicable to H.248) or RFC 3435 (applicable to MGCP) before configuring the TID format.

Context
The TID format consists of the terminal prefix and the TID template. The TID template defines the generation mode of the TID excluding the terminal prefix. A TID consists of a terminal prefix and a character string generated by a TID template.

The TID templates that are bound to various types of users on the MG interface determine whether the users support terminal layering.
If the parameter list of the TID template includes only keyword "G", the TID template is used by the non-layering users. Users bound with this template do not support terminal layering.
If the parameter list of the TID template includes only keywords "F", "S", "P", "B" ("B" is not available to PSTN users), the TID template is used by the layering users. Users bound with this template support terminal layering.
NOTE:
The meaning of each keyword is as follows:
F indicates the subrack ID.
S indicates the slot ID.
P indicates the port ID.
B indicates the B channel ID (only for ISDN BRA and ISDN PRA terminals).
G indicates the general permanent termination index.
R indicates the RTP ephemeral termination index (only for the RTP ephemeral termination, which exists only when the system protocol is H.248. This termination is not involved unless special remarks are provided.)
When adding a user that supports terminal layering, you cannot and do not have to specify the parameter terminalid because the system automatically allocates a terminal ID. When adding a user that does not support terminal layering, you must specify the parameter terminalid.

You can run the display tid-format(h248) command or display tid-format(mgcp) command to query the TID formats of various types of users on the current MG interface. In the query result, template-index indicates the index of the TID template that is bound to the type of users. Then, run the display tid-template command to check whether the TID template supports the layering configuration. Hence, you can check whether the user supports terminal layering.

Precaution
There are 19 default TID templates (templates 0-18) in the system. The default TID templates can be referenced, but cannot be added, modified, or deleted.
The configuration of terminal layering on the MG must be the same as that on the MGC.
If certain type of terminals exists on an interface and the interface is not disabled, the terminal prefix of this type of terminals cannot be modified.
If a certain type of terminals exists on an interface, the TID format (including the terminal prefix and the index of the TID template) of this type of terminals cannot be changed.
The terminal prefix must comply with the following syntax rules: The prefix must not exceed 64 characters. Only letters, digits, "_", and "/" are the characters allowed for input. The first character must be a letter, and the last character must not be a digit.
The length of the TID, which is generated by combining the TID template and the terminal prefix that you configured, must not exceed 64 characters.
Procedure
If the system protocol is H.248, to configure the TID format on the current MG interface, do as follows:
Run the display tid-template command to query the information about the default TID template of the system.
If the default TID template cannot meet the service requirements, run the tid-template add command to add a TID template that meets the service requirements. If the default TID template meets the service requirements, proceed to 3.
Run the interface h248 command to enter the H.248 mode.
Configure the TID templates and the terminal prefix of various types of users on the current MG (VAG).

NOTICE:
The terminal prefix of PSTN, BRA and PRA must be all identical or unique.
In the H.248 mode, run the tid-format rtp command to configure the TID template and the terminal prefix of the RTP ephemeral termination.
In the H.248 mode, run the tid-format pstn command to configure the TID template and the terminal prefix of the PSTN user.
In the H.248 mode, run the tid-format bra command to configure the TID template and the terminal prefix of the ISDN BRA user.
In the H.248 mode, run the tid-format pra command to configure the TID template and the terminal prefix of the ISDN PRA user.

Run the display tid-format(h248) command to check whether the TID templates and the terminal prefixes of various types of users on the current MG interface are the same as those in the data plan.
If the system protocol is MGCP, to configure the TID format on the current MG interface, do as follows:
Run the display tid-template command to query the information about the default TID template of the system.
If the default TID template cannot meet the service requirements, run the tid-template add command to add a TID template that meets the service requirements. If the default TID template meets the service requirements, proceed to 3.
Run the interface mgcp command to enter the MGCP , GPBD, GPFD mode.
Configure the TID templates and the terminal prefix of various types of users on the current MG (VAG).

In the MGCP mode, run the tid-format pstn command to configure the TID template and the terminal prefix of the PSTN user.
In the MGCP mode, run the tid-format bra command to configure the TID template and the terminal prefix of the ISDN BRA user.
In the MGCP mode, run the tid-format pra command to configure the TID template and the terminal prefix of the ISDN PRA user.

Run the display tid-format(mgcp) command to check whether the TID templates and the terminal prefixes of various types of users on the current MG interface are the same as those in the data plan.