Figure 57: Remote And Local T3 Loopback - Juniper JUNOS 10.1 - CONFIGURATION GUIDE 1-2010 Configuration Manual

or remote. With local loopback, the T3 interface can transmit packets to the CSU,
but receives its own transmission back again and ignores data from the CSU. With
remote loopback, packets sent from the CSU are received by the T3 interface,
forwarded if there is a valid route, and immediately retransmitted to the CSU.

Figure 57: Remote and Local T3 Loopback

To configure loopback capability on a T3 interface, include the
at the [edit interfaces interface-name t3-options]
[edit interfaces interface-name t3-options]
loopback (local | payload | remote);
Packets can be looped on either the local router or the remote CSU. Local and remote
loopback loop back both data and clocking information.
To exchange BERT patterns between a local router and a remote router, include the
loopback remote statement in the interface configuration at the remote end of the
link. From the local router, you issue the
For more information about configuring BERT, see "Interface Diagnostics" on page 146.
For more information about using operational mode commands to test interfaces,
see the JUNOS System Basics and Services Command Reference.
For channelized T3, T1, and NxDS0 IQ interfaces only, you can include the
statement in the configuration to loop back data only (without clocking
payload
information) on the remote router s PIC. In payload loopback, overhead is
recalculated. For T3 IQ interfaces, you can include the
at the
[edit interfaces ct3-fpc/pic/port]
hierarchy levels. For T1 interfaces, you can include the
in the configuration at the
is ignored if included at the
interfaces, payload and remote loopback are the same. If you configure one, the
other is ignored. NxDS0 IQ interfaces do not support local loopback.
To determine whether a problem is internal or external, you can loop packets on
both the local and the remote router. To do this, include the
statements at the
encapsulation cisco-hdlc
level and the loopback local
hierarchy level, as shown in the following example:
[edit interfaces]
t3-1/0/0 {
no-keepalives;
hierarchy level:
test interface
and
[edit interfaces t3-fpc/pic/port:channel]
[edit interfaces t1-fpc/pic/port:channel]
[edit interfaces ct1-fpc/pic/port]
[edit interfaces interface-name]
statement at the [edit interfaces interface-name t3-options]
Configuring T3 Loopback Capability
Chapter 32: Configuring T3 Interfaces
statement
loopback
command.
loopback
loopback payload statement
statement
loopback payload
hierarchy level; it
hierarchy level. For NxDS0
no-keepalives and
hierarchy
595