01-30-2007 08:01 AM - edited 03-05-2019 02:03 PM
I have a vlan interface on a 6513 that has shown a high level of input queue flushes. I am trying to understand the nature of what is causing this. I have included a few details below, and yes I have cleared the counters a week ago. I check this several times a day and these increment in bursts.
Vlan14 is up, line protocol is up
Hardware is EtherSVI, address is 000d.662d.fa80 (bia 000d.662d.fa80)
Description: 4th Floor Closet A
Internet address is 10.198.88.1/21
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:07, output hang never
Last clearing of "show interface" counters 6d23h
Input queue: 0/75/698/698 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 335000 bits/sec, 150 packets/sec
5 minute output rate 1189000 bits/sec, 194 packets/sec
L2 Switched: ucast: 17718 pkt, 4341606 bytes - mcast: 3471771 pkt, 855732428 bytes
L3 in Switched: ucast: 82294512 pkt, 27173808949 bytes - mcast: 0 pkt, 0 bytes mcast
L3 out Switched: ucast: 90072695 pkt, 70849844338 bytes mcast: 0 pkt, 0 bytes
85788885 packets input, 28030551254 bytes, 0 no buffer
Received 3471660 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
90238780 packets output, 70507594890 bytes, 0 underruns
0 output errors, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
The physical interfaces are clean, just the vlan interface is showing the flushes. What do you think?
01-30-2007 07:09 PM
Drops/flushes on a VLAN interface indicate some level of traffic hitting the MSFC CPU meaning that some of your traffic is being software-switched. While this is normal for some traffic types (ARP, routing protocol packets, etc.) there was a point in time where there was not enough queue space to accommodate these packets. You can increase the input queue size to try and rectify this:
example: Switch(config-if)#hold-queue 2000 in
and/or do RP inband sniffer traces to see what traffic is being punted to the CPU.
http://cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a00804916e0.shtml#utilities
Hope that helps.
09-16-2016 10:45 PM
Hello All,
I am having interface flushes packet count as 5. Is it will cause any issue?.. And please some one help to resolve this flushes.
CHN003P2#sh int gi4/0/0 | in drops|errors
Input queue: 1/1024/0/5 (size/max/drops/flushes); Total output drops: 0
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
Thanks,
Raja
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