4-6 Cisco BPX 8600 Series Reference
Broadband Network Interface Cards (BNI-T3 and BNI-E3)
Loopbacks and Diagnostics
There are two types of self-tests that may be performed. A non-disruptive self test is automatically
performed on a routine basis. A more complete, disruptive test may be initiated manually when a
card failure is suspected. If the card self-test detects a failure, the card status LEDs displays an
indication of the failure type.
Several loopback paths are provided. A digital card loopback path, used by the node for self-test,
loops the data at the serial DS3 or E3 interface back towards the node. A digital line loopback loops
the data at the electrical transmitter/receiver at the card output. Internally, the PLPP circuit in the
BNI-T3 has several loopbacks for use by diagnostic routines.
There are several loopback paths within the BNI for testing. A digital loopback at the DS3 or E3
transmitter/receiver to check both the transmit and receive signal paths in the near-end BNI card.
These loopbacks loop the signal in both directions, towards the StrataBus as well as towards the
output. Therefore, they can be used to support both near end and far end maintenance loopback
testing. On the BNI-3T3, there is a digital loopback capability to the PLPP processor used for the
internal self test to basically check the operation of the signal processor.
Once a trunk has been assigned to a BNI card but before it is made active (upped), it is put in a
loopback mode and a diagnostic test is continuously performed. This loopback is disruptive so it
cannot be performed on a card that has an active trunk. This diagnostic test checks the data path
through the BNI out to the BCC, through the switch matrix, and back to the BNI. Active trunks are
constantly checked by the Communications Fail test routine which is part of system software.
Front Panel Indicators
The lower section of the BNI front panel (see Figure 4-3) has a three-section, multicolored LED to
indicate the card status. The card status LED is color-coded as indicated in Table 4-1. At the upper
portion of the front panel, there is a three-section multicolored LED to indicate the status of the three
ports on the BNI. Types of failures are indicated by various combinations of the card status indicators
as indicated in Table 4-2.
Table 4-1 BNI Front Panel Status Indicators
Status LED color Status Description
Port off Trunk is inactive and not carrying data.
green Trunk is actively carrying data.
yellow Trunk is in remote alarm.
red Trunk is in local alarm.
Card green (act) Card is on-line and one or more trunks on the card have been upped. If off,
card may be operational but is not carrying traffic.
yellow (stby) Card is off-line and in standby mode (for redundant card pairs). May not
have any upped trunks. If blinking, indicates card firmware or
configuration data is being updated.
red (fail) Card failure; card has failed self-test and/or is in a reset mode.
