Loopback (T1/E1) - Cisco ASR 9000 Series Command Reference Manual

T3, E3, T1, E1 Controller Commands on the Cisco ASR 9000 Series Router

loopback (T1/E1)

To loop individual T1 or E1 channels on the channelized T3 controller, use the loopback command in T1 or
E1 configuration mode. To remove the loop, use the no form of this command.
loopback {local| network {line| payload}| remote {line {fdl {ansi| bellcore}| inband}| payload fdl ansi}}
no loopback {local| network {line| payload}| remote {line {fdl {ansi| bellcore}| inband}| payload fdl
ansi}}
Syntax Description
local
network {line |
payload}
remote line fdl
remote line inband
remote payload fdl
ansi
bellcore
Command Default
No loops are configured.
Command Modes
T1 configuration
Loops the router output data back toward the router at the T1 framer and sends an
alarm indication signal (AIS) signal out toward the network.
T1 loopback with encapsulation HDLC:
Loops the data back toward the network before the T1 framer and automatically sets
a local loopback at the High-Level Data Link Control (HDLC) controllers (line), or
loops the payload data back toward the network at the T1 framer and automatically
sets a local loopback at the HDLC controllers (payload).
T1 loopback with encapsulation PPP:
Loops the data back toward the network before the T1 framer and automatically sets
a local loopback at the PPP serial interface (line), or loops the payload data back
toward the network at the T1 framer and automatically sets a local loopback at the
PPP serial interface (payload).
(T1 only) Sends a repeating, 16-bit Extended Superframe (ESF) data link code word
(00001110 11111111 for FDL ANSI and 00010010 11111111 for FDL Bellcore) to
the remote end, requesting that it enter into a network line loopback.
(T1 only) Sends a repeating, 5-bit inband pattern (00001) to the remote end requesting
that it enter into a network line loopback.
(T1 only) Sends a repeating, 16-bit ESF data link code word (00010100 11111111)
to the remote end, requesting that it enter into a network payload loopback. Enables
the remote payload FDL ANSI bit loopback on the T1 channel.
(T1 only) Enables the remote line Facility Data Link (FDL) ANSI bit loopback on
the T1 channel, based on the ANSI T1.403 specification.
(T1 only) Enables the remote SmartJack loopback on the T1 channel, based on the
TR-TSY-000312 specification.
Cisco ASR 9000 Series Aggregation Services Router Interface and Hardware Component Command Reference,
loopback (T1/E1)
Release 5.3.x
1023