Specifications

7-89
Cisco MGX 8850 (PXM45) and MGX 8950 Software Configuration Guide
Release 3, Part Number 78-14788-01 Rev. C0, January 2004
Chapter 7 Switch Operating Procedures
Configuring a line loopback
In the following example, the user puts a sonet line into a local loopback state on an AXSM card.
MGX8850.1.11.AXSME.a > addlnloop -sonet 1.1 -lpb 2
Step 5 Enter the dspln -<line type> <line_num> command to verify the that the appropriate line is in the
specified loopback state.
8850_NY.10.AXSME.a > dspln -ds1 1.1
Line Number : 1.1
Admin Status : Down Alarm Status : Clear
Line Type : dsx1ESF Number of ports : 0
Line Coding : dsx1B8ZS Number of partitions: 0
Line Length(meters) : 40 Number of SPVC : 0
Loopback : Local Number of SPVP : 0
Xmt. Clock source : localTiming Number of SVC : 0
Valid Intervals : 0
Note Before you can change the loopback type for an existing loopback, you must first delete the loopback by
executing dellnloop, or you can just enter the addlnloop command with the -lpb 1 (No loopback) option.
Configuring a loopback line on Connection
A channel (or connection) loopback tests the integrity of the connection at the local UNI or across the
network. The maximum number of connection loopbacks that can exist on an AXSM is 256. Each
connection can have only one loopback at a time. Therefore, you cannot add a loopback on the receive
end and the transmit end at the same time. The loopback remains until you delete it by executing the
delchanloop command.
on a per-port basis, use the dspchanloop command.
Warning Do not run channel loopback test on a network that is not carrying live traffic. Channel loopback tests
are very intrusive.
bay.line Identifies the bay (1 or 2) and the number of the line. The line number can be
1 to the highest numbered line on the back card.
-lpb Specifies the loopback type for the line type. The entry for no loopback (1)
removes any existing loopback.
• 1 = No loopback
• 2 = Local loopback
• 3 = Remote loopback
Table 7-44 addlnloop Command Parameters
Parameter Description