Configuring a TDM clock source
E1 interfaces must use a common TDM clock source during timeslot interchange to prevent frame slips and bit errors.
When both E1 and T1 cards are present on a device, all the E1 or T1 SIC cards are a subsystem, and each E1 or T1 HMIM card is a subsystem. Each subsystem determines the clock source according to the following rules:
If the line keyword is specified for all interfaces, the clock on the interface with the lowest number is used. If the interface goes down, the clock on the interface with the second lowest number is used.
If the line and primary keywords are specified for one interface and the line or internal keyword is specified for all other interfaces, the clock on that one interface is used.
If the line keyword is specified for one interface and the internal keyword is specified for all other interfaces, the clock on that one interface is used.
The clock source of only one interface can be set to line primary.
The TDM clock sources on the local and peer devices must match. For example, if you set the clock source to line for a subsystem on the local device, you must set the clock source to internal on the peer device, and vice versa.
To configure a TDM clock source for an E1 interface:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter E1 interface view. | controller e1 number | N/A |
3. Configure a TDM clock source for the E1 interface. | tdm-clock { internal | line [ primary ] } | The default is internal. |