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High received broadcasts on Etherchannel link

IHCowan
Level 1
Level 1

Hi Everyone,

We having major network connectivity problems. I'm going to open a case with TAC but thought I would post here first.

I'm seeing a VERY high received broadcast count on 2 our our Cisco 3020 switches. Just wondering if this is normal. The Etherchannel link connects to a 6513.

Have a look below and thanks for any insight u might be able to provide.

Ian.

CHDCBCBSw1#sh int Po1

Port-channel1 is up, line protocol is up (connected)

Hardware is EtherChannel, address is 001d.e60d.8016 (bia 001d.e60d.8016)

Description: Etherchannel Link Core1

MTU 1500 bytes, BW 2000000 Kbit, DLY 10 usec,

reliability 255/255, txload 1/255, rxload 0/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 1000Mb/s, link type is force-up, media type is unknown

input flow-control is off, output flow-control is unsupported

Members in this channel: Gi0/21 Gi0/22

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

Last input 00:00:00, output 00:00:18, output hang never

Last clearing of "show interface" counters 00:30:50

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 0 bits/sec, 0 packets/sec

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

8030617 packets input, 3626319105 bytes, 0 no buffer

Received 18446744073695600912 broadcasts (31302 multicasts)

0 runts, 0 giants, 0 throttles

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

0 watchdog, 31302 multicast, 0 pause input

0 input packets with dribble condition detected

3414793 packets output, 4086804005 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 PAUSE output

0 output buffer failures, 0 output buffers swapped out

CHDCBCBSw1#sh ver

Cisco IOS Software, CBS30X0 Software (CBS30X0-LANBASEK9-M), Version 12.2(40)SE1, RELEASE SOFTWARE (fc1)

Copyright (c) 1986-2007 by Cisco Systems, Inc.

Compiled Tue 28-Aug-07 18:50 by myl

Image text-base: 0x00003000, data-base: 0x00E80000

ROM: Bootstrap program is CBS30X0 boot loader

BOOTLDR: CBS30X0 Boot Loader (CBS30X0-HBOOT-M) Version 12.2(25r)SEF3, RELEASE SOFTWARE (fc1)

CHDCBCBSw1 uptime is 1 year, 12 weeks, 1 day, 21 hours, 5 minutes

System returned to ROM by power-on

System restarted at 12:51:44 EST Fri Jan 4 2008

System image file is "flash:cbs30x0-lanbasek9-mz.122-40.SE1/cbs30x0-lanbasek9-mz.122-40.SE1.bin"

cisco WS-CBS3020-HPQ (PowerPC405) processor (revision D0) with 118784K/12280K bytes of memory.

Processor board ID FOC1140T0FN

Last reset from power-on

2 Virtual Ethernet interfaces

1 FastEthernet interface

24 Gigabit Ethernet interfaces

The password-recovery mechanism is enabled.

512K bytes of flash-simulated non-volatile configuration memory.

Base ethernet MAC Address : 00:1D:E6:0D:80:00

Motherboard assembly number : 73-10340-11

Motherboard serial number : FOC11394AUX

Model revision number : D0

Motherboard revision number : C0

Model number : WS-CBS3020-HPQ

System serial number : FOC1140T0FN

Top Assembly Part Number : 800-27541-02

Top Assembly Revision Number : D0

Version ID : V02

CLEI Code Number : IPUIAYGRAC

Hardware Board Revision Number : 0x04

Switch Ports Model SW Version SW Image

------ ----- ----- ---------- ----------

* 1 24 WS-CBS3020-HPQ 12.2(40)SE1 CBS30X0-LANBASEK9-M

2 Replies 2

Giuseppe Larosa
Hall of Fame
Hall of Fame

Hello Ian,

this looks an output error

8030617 packets input, 3626319105 bytes, 0 no buffer

Received 18446744073695600912 broadcasts (31302 multicasts)

0 runts, 0 giants, 0 throttles

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

0 watchdog, 31302 multicast, 0 pause input

0 input packets with dribble condition detected

the number of received broadcasts should be less then the total number of received packets

see for example from a TEngiga link of a 4510R-E

1489166305 packets input, 452090226552 bytes, 0 no buffer

Received 114528271 broadcasts (105136510 multicasts)

0 runts, 0 giants, 0 throttles

you see broadcast is less then total packets input

Of course there can be a real issue in the network but the broadcast count looks like unreal (if they follow the usual conventions of Cisco devices)

Hope to help

Giuseppe

Thanks Giuseppe,

Cisco TAC agrees that this must be an IOS bug.

Ian.

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