07-05-2009 10:15 PM - edited 03-04-2019 05:19 AM
Hi ALL:
I am have few drop on the input queue even after increasing the queue size.
The funny part is i dont see ant L2 or L3 switched packet on the interface .
When i did a etheral capture the only traffic is UDP for voice.
I have verified that CEF is working fine .
I have changed the ports and cable .
Any suggestions.
show interfaces gigabitEthernet 1/1
GigabitEthernet1/1 is up, line protocol is up
Hardware is C6k 1000Mb 802.3, address is 0005.7485.4014 (bia 0005.7485.4014)
Internet address is x.x.x.x/30
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s
ARP type: ARPA, ARP Timeout 04:00:00
Last clearing of "show interface" counters 00:51:34
Input queue: 0/1000/5596/5596 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue :0/40 (size/max)
30 second input rate 5322000 bits/sec, 715 packets/sec
30 second output rate 773000 bits/sec, 788 packets/sec
L2 Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes mcast
L3 out Switched: ucast: 0 pkt, 0 bytes
1616130 packets input, 1128926389 bytes, 0 no buffer
Received 17754 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
2021443 packets output, 277679018 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
Chao
Vishwa
07-06-2009 06:08 AM
What is the egress interface ?
07-06-2009 07:44 PM
Hi P,
The switch is connected to a 3750.
If thats what u are asking,but i dont understand why there is no L2 or L3 packet even though there is traffic.
Chao
Vishwa
07-07-2009 01:10 AM
Check what's going on on the output interface.
Display output may be irrelevant.
07-07-2009 01:33 AM
Hi P,
Interface gi1/1 is the output interface connected to 3750.
Chao
Vishwa
07-07-2009 08:30 PM
Hi P,
This is what i found:
1.From show interface status
Input queue: 0/2500/308438/308438 (size/max/drops/flushes)
2.From show interface switching for gi1/1
Throttle count 0
Drops RP 308293 SP 0
SPD Flushes Fast 308293 SSE 0
3.From debug ip traffic
Drop: 657562 encapsulation failed, 0 unresolved, 0 no adjacency
750915 no route, 0 unicast RPF, 0 forced drop
From the first 2 output we see that the Number of flushes and drops are same in input queue .
From the interface switching output the drops are also matching.
From the 3rd output we see that the total number of dropped packet for all the interface and Vlan is combination of Encapsulation and No route.
Encapsulation failed indicates that the router has no ARP request entry for a particular destination or is due to the fact that an interface is down.
No route errors occur when the router does not have a route in its routing table
So i guess i have check for virus and arp issue first then routing.
Chao
Vishwa
07-08-2009 01:17 PM
Your input queue drops are caused by spd flushes. Search for "Selective Packet Discard" - I think the command you want is
ip spd queue max
My experience has been that the 6500s have the charming property of NOT automatically changing the SPD threshold. So no matter what your input q size is it still acts like it's set to the default 75.. the only difference is you get input q flushes instead of drops.
For whatever it's worth, everything I've read indicates that packets are put on the input queue only when the MSFC has to process them - so you need to be looking for pkts punted to the MSFC, broadcasts & pkts addressed to the router. An excessive number of ARP requests could do it. Unless you're doing something horrid like pointing a static route at an ethernet interface I kind of doubt a virus would be giving your router heartburn..
HTH,
Lee
07-08-2009 02:27 PM
Lee, nice analysis here. Seems to me you take networking the right way.
07-08-2009 10:55 PM
Hi Lee,
Thanks a lot for clearing the doubt.
I knew that SPD is happening but had no idea on what you have explained ,i am going to use this command and wait for the magic.
Chao
Vishwa
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