R2511-HP MSR Router Series Interface Configuration Guide(V5)

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The local end sends out a pattern, which is to be looped over somewhere on the line and back to the
local end. The local end then checks the received pattern for the bit error rate, and by so doing helps you
determine whether the condition of the line is good. To this end, you must configure loopback to allow
the transmitted pattern to loop back from somewhere on the line, for example, from the far-end interface
by placing the interface in far-end loopback.
You may view the state and result of the BERT test with the display ft1 serial command.
To start/terminate a BERT test on a T1-F interface:
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter T1-F interface view.
interface serial interface-number N/A
3. Start a BERT test.
ft1 bert pattern { 2^20 | 2^15 }
time minutes [ unframed ]
By default, no BERT test is
performed.
Displaying and maintaining T1-F interfaces
Task Command Remarks
Display information about a
specified or all T1-F interfaces.
display ft1 [ serial interface-number ] [ |
{ begin | exclude | include }
regular-expression ]
Available in any view.
Display the status of a specified
T1-F interface.
display interface serial serial-number [ |
{ begin | exclude | include }
regular-expression ]
Available in any view.
Configuring a CE3 interface
Overview
Like E1, E3 also belongs to the digital carrier system of ITU-T. It transmits data at 34.368 Mbps and
adopts HDB3 as the line code format.
A CE3 interface can operate in either E3 or CE3 (the default) mode.
• A CE3 interface in E3 mode is an interface with 34.368 Mbps data bandwidth, on which, no
timeslots are divided. The system automatically creates a serial interface numbered serial
number/line-number/0:0 for it. This interface operates at 34.368 Mbps and is logically equivalent
to a synchronous serial interface where you can make other configurations.
• A CE3 interface in CE3 mode can demultiplex 16 channels of E1 signals in compliance with ITU-T
G.751 and G.742. Each E1 line can be divided into 32 timeslots numbered 0 to 31, of which
timeslots 1 through 31 can be randomly bundled into N × 64 kbps logical channels. (Timeslot 0 for
framing signal transmission must not participate in bundling operation.) Therefore, CE3 can be
channelized into E1 lines or CE1 lines.
When an E1 line is operating in unframed (E1) mode, the system automatically creates a serial interface
numbered serial number/line-number:0 for it. This interface operates at 2048 kbps and is logically
equivalent to a synchronous serial interface where you can make other configurations.