December 2001
Intermediate to advanced
608 pages
25h 14m
English
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Name
loopback — interface
Synopsis
loopback [options]
no loopbackConfigures
Loopback mode
Default
Disabled
Description
The loopback command sets the equipment at some
point between a router interface and the other end of the line to
reflect all data back to the router. Loopbacks are extremely useful
for troubleshooting. With no options, loopback
tests the local interface: all packets sent to the interface are
immediately reflected back to the router without being sent to the
destination. The various options and
parameters allow you to place the loopback point farther down the
line:
-
applique Sets the internal loopback for an HSSI interface.
-
dte Sets the loopback at the CSU/DSU, which tests the cable between the router (the DTE) and the CSU/DSU. The CSU/DSU must support this option.
-
line[payload] Sets the loopback at the “far end” of the CSU/DSU, which sends the packets completely through the CSU/DSU and back to the router. The CSU/DSU must support this option. On routers with built-in CSU/DSUs (2524 or 2525) you can add the
payloadkeyword, which creates the loopback at the DSU.-
remoteoption Sets the loopback at the remote CSU/DSU, which sends packets all the way to the remote end of the connection before reflecting them back to the router. This command tests the entire communications link between the router and the far end of the line. The remote CSU/DSU must be configured for remote loopback. Additional options give you more control over the behavior of remote loopback.
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.