Chapter 20
Troubleshooting the Serial SPAs
Note
This section describes how to use the show interfaces serial command to diagnose serial line
connectivity problems in a wide-area network (WAN) environment. The following sections describe
some of the important fields of the command output:
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Serial Lines: show interfaces serial Status Line Conditions
You can identify five possible problem states in the interface status line of the show interfaces serial
display:
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The following example shows the interface statistics on the first port of a 4-Port Clear Channel T3/E3
SPA installed in subslot 0 of the SIP located in chassis slot 5:
Router# show interfaces serial
Serial5/0/0 is up, line protocol is up
Hardware is SPA-4T3E3
Internet address is 110.1.1.2/24
MTU 4470 bytes, BW 44210 Kbit, DLY 200 usec,
Encapsulation HDLC, crc 16, loopback not set
Keepalive set (10 sec)
Last input 00:00:05, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 40685000 bits/sec, 115624 packets/sec
5 minute output rate 40685000 bits/sec, 115627 packets/sec
OL-14127-08
The output of the show interfaces serial command will vary depending on the type of serial
SPA.
Serial Lines: show interfaces serial Status Line Conditions, page 20-3
Serial Lines: Increasing Output Drops on Serial Link, page 20-7
Serial Lines: Increasing Input Drops on Serial Link, page 20-8
Serial Lines: Increasing Input Errors in Excess of 1 Percent of Total Interface Traffic, page 20-9
Serial Lines: Troubleshooting Serial Line Input Errors, page 20-10
Serial Lines: Increasing Interface Resets on Serial Link, page 20-13
Serial Lines: Increasing Carrier Transitions Count on Serial Link, page 20-14
Serial x is down, line protocol is down
Serial x is up, line protocol is down
Serial x is up, line protocol is up (looped)
Serial x is up, line protocol is down (disabled)
Serial x is administratively down, line protocol is down
reliability 255/255, txload 234/255, rxload 234/255
4653081241 packets input, 204735493724 bytes, 0 no buffer
Received 4044 broadcasts (0 IP multicast)
0 runts, 0 giants, 0 throttles
0 parity
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
4652915555 packets output, 204728203520 bytes, 0 underruns
0 output errors, 0 applique, 4 interface resets
Cisco ASR 1000 Series Aggregation Services Routers SIP and SPA Software Configuration Guide
Performing Basic Interface Troubleshooting
20-3