loopback (ADSL, DS0, E1/E3, SONET/SDH, SHDSL, and T1/T3)
Syntax
Hierarchy Level
Release Information
Statement introduced before Junos OS Release 7.4.
Description
Configure a loopback connection. To turn off the loopback capability, remove the loopback statement from the configuration.
When configuring CE1 or CT1 interfaces on 10-port Channelized E1/T1 IQE PICs, the loopback statement must be included with the local or remote option at the [edit interfaces ce1-fpc/pic/port] or [edit interfaces ct1-fpc/pic/port] hierarchy level as appropriate.
When configuring T1 interfaces on 10-port Channelized E1/T1 IQE PICs, the loopback statement must be included with the payload option at the [edit interfaces t1-fpc/pic/port] hierarchy level.
When configuring CE1 or CT1 interfaces on the 16-port Channelized E1/T1 MIC (MIC-3D-16CHE1-T1-CE), you must include the loopback statement at the [edit interfaces ce1-fpc/pic/port] hierarchy level, or [edit interfaces ct1-fpc/pic/port]
To configure loopback on channelized IQ and IQE PICs, SONET/SDH level, use the sonet-options loopback statement local and remote options at the controller interface (coc48, cstm16, coc12, cstm4, coc3, cstm1). It is ignored for path-level interfaces so-fpc/pic/port or so-fpc/pic/port:channel.
Options
local—Loop packets, including both data and timing information, back on the local router’s PIC. NxDS0 IQ interfaces do not support local loopback.
payload—For channelized T3, T1, and NxDS0 IQ interfaces only, loop back data only (without clocking information) on the remote router’s PIC. With payload loopback, overhead is recalculated. Neither ATM-over-asymmetrical digital subscriber line (ADSL) interfaces nor ATM-over-SHDSL interfaces support payload loopback.
remote—Loop packets, including both data and timing information, back on the remote router’s interface card. NxDS0 IQ interfaces do not support remote loopback.
Required Privilege Level
interface—To view this statement in the configuration.
interface-control—To add this statement to the configuration.