Solving output drops and input errors

[jtillman11]

Below is output from the LAN interface on our Cisco 1941 router. This interface connects directly to a port on an HP Procurve switch. Note the output errors, CRC error, and input errors in bold. I have read several posts and articles describing what these are but I am at a loss at how to correct them. I can post additional information as needed.

GigabitEthernet0/0 is up, line protocol is up
Hardware is CN Gigabit Ethernet, address is a493.4c42.d4e0 (bia a493.4c42.d4e0)
Description: G0/0 LAN Interface
Internet address is 10.0.3.1/24
MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
reliability 255/255, txload 2/255, rxload 4/255
Encapsulation 802.1Q Virtual LAN, Vlan ID 1., loopback not set
Keepalive set (10 sec)
Full Duplex, 100Mbps, media type is RJ45
output flow-control is unsupported, input flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/2 (size/max/drops/flushes); Total output drops: 2698225
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 1866000 bits/sec, 276 packets/sec
5 minute output rate 785000 bits/sec, 224 packets/sec
3810276624 packets input, 1578361743 bytes, 2697505 no buffer
Received 57105739 broadcasts (35039136 IP multicasts)
0 runts, 0 giants, 0 throttles
2 input errors, 1 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 44759351 multicast, 0 pause input
2365867680 packets output, 921099490 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
9 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

[jtillman11]

I was able to enable "buffers tune automatic" so we will see how that does, thank you.

According to the whitepaper, the maximum throughput of the 1941 is 569Mbps. We are not doing VPN, QoS, or PAT on this router. I don't see a limit of 25Mbps in that whitepaper, am I overlooking something?

[Joseph W. Doherty · Accepted solution]

"According to the whitepaper, the maximum throughput of the 1941 is 569Mbps."

Actually the whitepaper has the 1941's maximum throughput as 2,932 Mpps (see table one). Your 569 Mbps value is from table four, correct?

This gen of ISRs performance depends very much on traffic mix and configuration. It's very, very variable.

"I don't see a limit of 25Mbps in that whitepaper, am I overlooking something?"

No, it's not a limit, just a Cisco recommendation, see figure one (end of document).

Those Cisco recommendations are very conservative, to help insure a certain level of performance might always be obtained, regardless of traffic or configuration. But, indeed, when not doing VPN, QoS or PAT (etc.), yes likely you can obtain more than 25 Mbps (duplex). That said, I would consider a 1941 a bit light for full 100 Mbps (if that's what you're working with). If your CPU isn't peaking at 100%, you should be good for now.