Specifications

2-74
Cisco IGX 8400 Series Provisioning Guide, Release 9.3.3 and Later Releases
OL-1166-04
Chapter 2 Cisco IGX 8400 Series Cards
Frame Relay Module
Port Testing on the FRI-X.21 Back Card
To test FRI-X.21 back card ports and any associated external modems, CSUs, or NTUs, set up data
loopback points in the circuit path using one of the following loopbacks:
• An internal port loopback
• A loopback of the near end (local) modem
• A loopback of the far end (remote) modem
To set up a loopback test, use the switch software tstport command. You can only test one port in
loopback mode at a time.
Tip Any modem being used to test FRI-X.21 back card ports must be compatible with Cisco loopback
protocols. For more information on these protocols and on supported modems, see Appendix A, “System
Specifications”, in the Cisco IGX 8400 Series Installation Guide or refer to the Cisco WAN Switching
Command Reference for protocol requirements for the switch software commands addextlp, addloclp,
and addrmtlp.
The internal loopback point is established inside the FRI-X.21 back card, as shown in Figure 2-34. The
FRM front card generates a test pattern, sends the test pattern out on the transmit circuitry, and detects
the returned pattern on the receive circuitry.
Tip To avoid disruptions in service, conduct loopback tests during periods of low network traffic. The test
takes several seconds and will momentarily interrupt traffic on the port.
Figure 2-34 FR Loopback Modes
Frame Relay Interface T1 and E1 Back Cards
The FR interface T1 and E1 back cards (the FRI-T1 and FRI-E1) are one-line back cards with either a
T1 or E1 interface, for use with the channelized FRM front card (Models E or J). For a description of
the back card faceplates, see Figure 2-35. For a definition of the faceplate LEDs, see Table 2-44.
Fri
X.21
port
(DTE)
Fri
X.21
port
(DTE)
IPX
Internal
loopback
Local
loopback
Remote
loopback
User
Remote
NTU
Local
NTU
T
R
T
R
H8078
Transmission facility