Verifying The Configuration; Troubleshooting Cpos Interfaces; Interface Physical Status Is Up, Link Protocol Status Is Down, And Loopback Is Detected - HP MSR Router Series Configuration Manual

[RouterB-E1 2/4/2] quit
# Create MP-group 1 and assign an IP address to it.
[RouterB] interface mp-group 1
[RouterB-Mp-group1] ip address 10.1.1.2 24
[RouterB-Mp-group1] quit
# Assign Serial 2/4/1:0 to MP-group 1.
[RouterB] interface serial2/4/1:0
[RouterB-Serial2/4/1:0] ppp mp mp-group 1
[RouterB-Serial2/4/1:0] quit
# Assign Serial 2/4/2:0 to MP-group 1.
[RouterB] interface serial2/4/2:0
[RouterB-Serial2/4/2:0] ppp mp mp-group 1
[RouterB-Serial2/4/2:0] quit

Verifying the configuration

# Verify the serial interface configuration and state, for example, on Router B.
<RouterB> display interface serial 2/4/1:0
# Verify the MP interface, and MP bundle configuration and state, for example, on Router B.
<RouterB> display interface mp-group 1
<RouterB> display interface display ppp mp
# Verify that the routers can ping one another. (Details not shown.)

Troubleshooting CPOS interfaces

Interface physical status is up, link protocol status is down, and
loopback is detected
Symptom
The HP router is connected to another vendor's router through E1 channels on CPOS interfaces across an
SDH network. PPP is used on the serial interface created for the E1 channel set.
The output from the display interface serial command shows the following errors:
The physical state of the serial interface is up, but the link protocol is down.
•
• The serial interface is in a looped condition, even though loopback detection is not configured on
the interface.
Solution
The symptom might occur when the router and its directly connected SDH device have different multiplex
paths for the E1 channels. Multiplex path inconsistency can cause PPP negotiation failure because the
SDH device transmits signals from the router in incorrect timeslots to the remote end. If the SDH device
incorrectly maps a signal to an idle timeslot in a looped condition, the router can detect a loop on the
serial interface.
To resolve the problem:
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