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Ignored packets on trunk interface

Int GI0/1
0 input errors, 0 CRC, 0 frame, 0 overrun, 21068 ignored

In a local PC lab, the Cisco sw (2950 48 port) is showing alot of ignored packtes, but no input errors. I have found alot of articles that describe if you input errors and ignored packets, but I only have ignored packets. Uplink is a simple trunk config.  I am speculating that the upstream sw is throwing too much data for the 2950 to handle.

1) What is the reason for ignored packets?

2) Why below do I have misses for the buffers?

3) The very bottom output is showing recv'd errors, is this a physical issue or too much data being sent to the 2950?

SW-01#sh buffers
Buffer elements:
499 in free list (500 max allowed)
686139171 hits, 0 misses, 0 created

Public buffer pools:
Small buffers, 104 bytes (total 60, permanent 25, peak 87 @ 7w0d):
60 in free list (20 min, 60 max allowed)
682857392 hits, 2243 misses, 2658 trims, 2693 created
0 failures (0 no memory)
Middle buffers, 600 bytes (total 21, permanent 15, peak 79 @ 7w0d):
17 in free list (10 min, 30 max allowed)
30943364 hits, 189882 misses, 105605 trims, 105611 created
82307 failures (0 no memory)
Big buffers, 1524 bytes (total 6, permanent 5, peak 34 @ 7w0d):
6 in free list (5 min, 10 max allowed)
2227513 hits, 64542 misses, 31682 trims, 31683 created
44163 failures (0 no memory)
VeryBig buffers, 4520 bytes (total 10, permanent 0, peak 14 @ 7w0d):
10 in free list (0 min, 10 max allowed)
221266 hits, 22990 misses, 1631 trims, 1641 created
22987 failures (0 no memory)
Large buffers, 5024 bytes (total 1, permanent 0, peak 8 @ 7w0d):
1 in free list (0 min, 5 max allowed)
5586 hits, 17401 misses, 3476 trims, 3477 created
17401 failures (0 no memory)
Huge buffers, 18024 bytes (total 1, permanent 0, peak 4 @ 7w0d):
1 in free list (0 min, 2 max allowed)
2169 hits, 15232 misses, 3345 trims, 3346 created
15232 failures (0 no memory)

Interface buffer pools:
Calhoun Packet Receive Pool buffers, 1560 bytes (total 512, permanent 512):
447 in free list (0 min, 512 max allowed)
376306583 hits, 0 misses
SW-01#sh interfaces counters err

Port Align-Err FCS-Err Xmit-Err Rcv-Err UnderSize
Gi0/1 0 0 0 21068 0

SW-01#sh int gi0/1 sum

*: interface is up
IHQ: pkts in input hold queue IQD: pkts dropped from input queue
OHQ: pkts in output hold queue OQD: pkts dropped from output queue
RXBS: rx rate (bits/sec) RXPS: rx rate (pkts/sec)
TXBS: tx rate (bits/sec) TXPS: tx rate (pkts/sec)
TRTL: throttle count

* GigabitEthernet0/1 0 3792 0 0 35000 47 2000 3 0
NOTE:No separate counters are maintained for subinterfaces
Hence Details of subinterface are not shown

SW-01#sh int gi0/1 counters err

Port        Align-Err    FCS-Err   Xmit-Err    Rcv-Err UnderSize
Gi0/1               0          0          0        21068 0

Thank you

Everyone's tags (4)

Ignored packets on trunk interface

I forgot to add that I cleared counters, and the ignore number still increments.


Ignored packets on trunk interface

That interface seems to be overlaoded, packets can not find free buffers to match their MTU size, thats why they are ignored. if performance is bad, contact Cisco TAC, they will guide you in the right directions.


Posted by WebUser Neeraj Jagga from Cisco Support Community App

New Member

Ignored packets on trunk interface

Can you provide the output from:

show int gi0/1

show run int gi0/1

And what is it connected to? If it's another cisco device, also do a

show cdp neigh g0/1 det



Ignored packets on trunk interface

Thanks Andy, I rebooted both switches last night, and all computers in the labs in question did the updates fine.    The ignored counter was constantly incrementing on both switches (no other meaning counter minus traffic passing was incrementing).  I rebooted the switches, and the ignored counter stopped (and still stopped this morning last check about .023 seconds ago :).  The output below is after the reboot:

SW-01#sh int gi0/1
GigabitEthernet0/1 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 000a.8ae9.b9f1 (bia 000a.8ae9.b9f1)
  MTU 1500 bytes, BW 1000000 Kbit, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s
  input flow-control is off, output flow-control is off
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:01, output 00:00:01, 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 52000 bits/sec, 59 packets/sec
  5 minute output rate 1000 bits/sec, 2 packets/sec
     1820505 packets input, 153050994 bytes, 0 no buffer
     Received 1795296 broadcasts (0 multicast)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 1291386 multicast, 0 pause input
     0 input packets with dribble condition detected
     20062 packets output, 2123687 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out
SW-01#sh cdp nei
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
                 Gig 0/1            161         R S I     WS-C6509  Gig 5/6
SW-01#sh run int gi0/1
Building configuration...

Current configuration : 79 bytes
interface GigabitEthernet0/1
switchport mode trunk
mls qos trust dscp

Sh ver on 2950:

System image file is "flash:c2950-i6q4l2-mz.121-20.EA1a.bin"

From upstream sw:

0277-RTR-01#sh run int gi5/6
Building configuration...

Current configuration : 129 bytes
interface GigabitEthernet5/6
mls qos trust dscp
switchport trunk encapsulation dot1q
switchport mode trunk

A senior guy sent me an article:

Understanding Buffer Misses and Failures

Document ID: 14620

Which I shall read.

Thank you