T1-F Interface Overview; T1-F Interface Features Supported By The Ar1200 - Huawei AR1200 series Configuration Manual

Huawei AR1200 Series Enterprise Routers
Configuration Guide - Interface Management

9.1 T1-F Interface Overview

This section describes the concepts of T1-F interfaces.
Introduction to T1-F Interfaces
A T1-F interface is a T1 interface working in fractional channelized mode. It is a simplified
version of a CT1/PRI interface. If T1 access does not need multiple channel sets or the ISDN
PRI function, using CT1/PRI interfaces wastes resources. To reduce costs, T1-F interfaces can
be used in this T1 access scenario.
A T1-F interface works only in framed mode. In this mode, a T1-F interface is divided into 24
timeslots, which are numbered 1 to 24. All the 24 timeslots can be bundled into a channel. The
rate of a T1-F interface is n x 64 kbit/s or n x 56 kbit/s, in which n is the number of timeslots
bundled into a channel. A T1-F interface is similar to a synchronous serial interface and supports
link layer protocols such as the Point-to-Point Protocol (PPP), High-Level Data Link Control
(HDLC), and Frame Relay (FR) and network protocols such as IP.

9.2 T1-F Interface Features Supported by the AR1200

This section describes T1-F interface physical attributes supported by the AR1200.
Clock Mode
To exchange data correctly, communicating parties must have their clocks synchronized.
A T1-F interface works in either of the following clock modes:
l
l
Generally, the interface at one end of a link works in master clock mode, and the interface at the
other end works in slave clock mode.
Frame Format
A T1-F interface supports the following frame formats:
l
l
Line Idle Code
The line idle code is the code sent over a timeslot that is not bundled to form a channel.
The AR1200 supports two line idle codes: 0x7e and 0xff.
Issue 01 (2012-04-20)
In master clock mode, the T1-F interface uses the local clock generated by the chip as the
reference clock.
In slave clock mode, the T1-F interface uses the line clock as the reference clock.
Extended super frame (ESF): consists of 24 frames that share the same frame alignment
information and signaling information. Frames 6, 12, 18, and 24 are signaling frames.
Super frame (SF): consists of 12 frames that share the same frame alignment information
and signaling information. Frame 6 and frame 12 are signaling frames.
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