Cisco 7401ASR Installation And Configuration Manual page 105

Chapter 5 Troubleshooting
Note CPU usage becomes more efficient as packet load increases. For example, if you are running at 60% CPU
with only 33% of customer load on the system, this does not mean that you need 180% CPU for 100%
of customers. Part of the original 60% CPU usage is overhead usage, which does not increase as packet
load increases.
Ignored Packets
Packet ignores on an interface may result from high CPU usage. Enter the show interfaces command to
display any input ignores:
Router# show interfaces ethernet 0/0
Packets are ignored if there is no available CPU to accept the new packet. This can happen if the router
is overloaded with traffic, but can also happen if the interface is faulty. If ignores are present on all
interfaces, then the router is probably overloaded with traffic, or does not have sufficient free buffers in
the pool that match the maximum transmission unit (MTU) on interfaces. In the latter case, an increment
of the ignored counter is followed by an increment of the no buffer counter:
Router# show interfaces serial 0/0
OL-5419-01 B0
Packets ignored:
shadow ring full:
in ring full:
PXF inactive:
tx credits:
holdq enqueues:
interrupts:
interrupt packets:
pending read bytes:
Interface Pkts In
Fa0/0
Et1/0
Et1/1
Et1/2
Et1/3
Se2/0
Se2/1
Se2/2
Se2/3
Fa3/0
PO4/0 30000000 1440000000
AT5/0
Vi1
Vt1
Vi2
Vt2
Ethernet0/0 is up, line protocol is up
...
21 input errors, 0 CRC, 0 frame, 0 overrun, 21 ignored
...
1567 packets input, 0 bytes, 22 no buffer
22 input errors, 0 CRC, 0 frame, 0 overrun, 22 ignored, 0 abort
0 | ring space:
0 | shadow ring:
0 | inring:
0
16230330 | delayed credits:
0 | requeue drops:
40538 | interrupt misses:
53326
0
Chars In Pkts Out
0 0 30000000 1740000000
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
Cisco 7401ASR Installation and Configuration Guide
PXF Troubleshooting Information
16384
968
1947
Chars Out Punted
970
0 21309
0 0
0 0
0 0
0 963
0 0
0 0
0 0
0 963
0 963
0 23192
0 0
0 0
0 0
0 0
0
0
Dropped
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5-9