Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Catalyst 2950 interface problem

Hi, Sirs.

My Catalyst 2950-24 (IOS Ver 12.1.22EA7)stops communicate with an other switch port of a Catalyst 3512XL-EN after catalyst 2950 powered on 1 or 2 days.

th show interface shows that 2476498 ignored.

FastEthernet0/1 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 000d.28c0.cf41 (bia 000d.28c0.cf41)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s, media type is 100BaseTX

input flow-control is unsupported output flow-control is unsupported

ARP type: ARPA, ARP Timeout 04:00:00

Last input 3d19h, output 00:00:00, 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 28000 bits/sec, 44 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

10033048 packets input, 806430104 bytes, 2476489 no buffer

Received 10031591 broadcasts (0 multicast)

0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 2476498 ignored

0 watchdog, 2217265 multicast, 0 pause input

0 input packets with dribble condition detected

357799 packets output, 25835259 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

what does is mean?


Re: Catalyst 2950 interface problem


Ignored counter is all about number of frames dropped on input due to resource exhaustion in the switch fabric..

More info will be required on the config part of the port like whether the port is configured as access port or trunk port..

Also if you check the no buffer counter 2476489 its very much evident that your switch was out of resources to recieve it..

The workaround is to reduce the traffic load on the particular interface.

for more info and troubleshooting purpose u can make use of this link..

If possible try to patch up the GBIC ports available on both 2950 and 3512 which may make some difference in the performance or replace the 3512 with the another 2950 itself which is the possible replacement pointed out by cisco.



Re: Catalyst 2950 interface problem


Note that the value "2476489 no buffer" is related to the "2476498 ignored" frames.

"no buffers"

Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernet networks and bursts of noise on serial lines are often responsible for no input buffer events.

Please post the configuration for Fa0/1 for further assistance.



* Please rate useful posts.


Re: Catalyst 2950 interface problem


what other switches do you have in your network ? If you have just the 2950 and the 3500, make sure that the 2950 is the root switch for all your VLANs, by configuring the global command:

spanning-tree vlan x priority 0

Also, check the log on the 2950 for the following message:


If you see those, chances are that you have a faulty unit. Here is the relevant bug info:

CSCdv83336 Bug Details

Under certain level of traffic load, the (2950) switch will start logging the following messages on the console:


and after a few seconds, the switch will stop passing any traffic. In some cases, the switch seemed still forwarding broadcast and multicast traffic, which will cause STP problem if the switch has redundant link and is not supposed to be the root for the VLAN, as both port will go forwarding.

The same error message has been identified in CSCdu87836.

An assessment of the impact

Unit stops passing any traffic.


Several units were returned by CISCO. The units were re-screened to the latest test program, and failed the SDRAM memory test.

Customer should RMA unit back to Cisco



CreatePlease login to create content