Specifications

Configure a Channelized T3 Interface Processor
IC-88
Cisco IOS Interface Configuration Guide
Figure 14 CT3IP Network Payload Loopback
Figure 15 shows an example of a remote inband loopback in which the network line enters a line
loopback.
Figure 15 CT3IP Remote Loopback
Loopback T3 Lines
You can put the entire T3 line into loopback mode (that is, all T1 channels are looped) by using the
following types of loopbacks:
Local—Loops the router output data back toward the router at the T1 framer and sends an AIS
signal out toward the network.
Network—Loops the data back toward the network (before the T1 framer).
Remote —Sends a FEAC (far-end alarm control) request to the remote end requesting that it enter
into a network line loopback. FEAC requests (and therefore remote loopbacks) are only possible
when the T3 is configured for C-bit framing. The type of framing used is determined by the
equipment you are connecting to. (For more information, see the framing controller command.)
S5683
HDLC
controllers T1 channels
Channel 1
Channel 2Controller 2
CT3IP
T3 output
MUX
Channel 28Controller 28
Controller 1
S5684
Network cloud
Remote
CSU/DSU
HDLC
controllers T1 channels
Controller 1 Channel 1
Channel 2Controller 2
CT3IP
T3 output
MUX
Channel 28Controller 28