Configuring a CT3 interface
Both T3 and T1 belong to the T-carrier system promoted by ANSI. T3 uses the digital signal level DS-3 and operates at 44.736 Mbps.
CT3 interfaces support the T3 (unchannelized) mode and the CT3 (channelized) mode.
In T3 mode, a CT3 interface provides 44.736 Mbps of data bandwidth. No timeslots are divided. The system automatically creates a synchronous serial interface for it. The serial interface name uses the serial number/0:0 format.
In CT3 mode, a CT3 interface can be demultiplexed into 28 channels of T1 signals. Each T1 line can be divided into 24 timeslots numbered 1 through 24. Each line on a T1 interface can operate at either 64 kbps or 56 kbps.
The following are schemes available for creating different rates of T1 lines on a CT3 interface in CT3 mode:
M × 1.536 Mbps. (M is an integer in the range of 1 to 28.)
N × 56 kbps or N x 64 kbps. (N is an integer in the range of 1 to 24.)
A T1 line can operate in T1 or CT1 mode.
If the T1 line operates in unframed (T1) mode, the system automatically creates a 1544 kbps serial interface for it. The serial interface name uses the serial number/line-number:0 format.
If the T1 line operates in framed (CT1) mode, you can bundle timeslots on it. The system automatically creates a synchronous serial interface for it. The serial interface name uses the serial number/line-number:set-number format. This interface operates at n × 64 kbps or n × 56 kbps, where n is the number of bundled timeslots.
The synchronous serial interface created in T3 or CT3 mode has the same logical features as a standard synchronous serial interface and supports the following protocols:
Data link layer protocols, such as PPP and HDLC.
Network layer protocols, such as IP.
You can configure this interface in the same way you configure a standard synchronous serial interface.