R2511-HP MSR Router Series Interface Command Reference(V5)

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loopback (CE1/PRI interface)
Use loopback to enable loopback and set the loopback mode.
Use undo loopback to restore the default.
Syntax
loopback { local | payload | remote }
undo loopback
Default
Loopback is disabled.
Views
CE1/PRI interface view
Default command level
2: System level
Parameters
local: Sets the interface in local loopback mode.
remote: Sets the interface in external loopback mode.
payload: Sets the interface in external payload loopback mode.
Usage guidelines
Loopback is mainly used to check the condition of interfaces or cables. Disable loopback in other cases.
You can bundle timeslots on the CE1/PRI interface to form a serial interface and encapsulate it with PPP.
After you enable loopback on this serial interface, it is normal that the state of the link layer protocol is
reported as down.
Examples
# Set interface E1 2/0 in internal loopback mode.
<Sysname> system-view
[Sysname] controller e1 2/0
[Sysname-E1 2/0] loopback local
looptest (CE1/PRI interface)
Use looptest to perform a loop test on a synchronous serial interface created for E1 or E1-F.
Syntax
looptest [ -c count | -p { pattern | special { ascending | descending | random } } | -s packetsize | -t
timeout ] * interface type number
Views
Any view
Parameters
-c count: Sets the number of test packets, in the range of 1 to 1 to 4294967295. The default number is
5.