Dropped Pings Cisco Stack

[ohareka70]

Hello,

I have 3 sites with a 1GB link between them.  The root bridges on each Layer 3 switch is setup for different server vlans to carry them to each site.  All has been working ok until a week ago.  The config has not changed but we did lose power to one of the sites and it had to be repowered.

Just curious but does anyone have any experience of dropped packets on the network.  Is it possible their is a physical link issue?  Spanning tree seems fine.  Could it be latency on the links being caused by a server?

The switches are Cisco 3750

4pm

rtrDERGWWcorp01#

Ping Target IP address: 10.1.1.1

Repeat count [5]: 1000

Sending 1000, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!

Success rate is 99 percent (998/1000), round-trip min/avg/max = 12/15/40 ms

7pm

AFTER THE CHANGE to a root bridge

Ping Target IP address: 10.1.1.1

Repeat count [5]: 1000

Sending 1000, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Success rate is 99 percent (999/1000), round-trip min/avg/max = 12/15/40 ms

[Kushagra Kaushik]

Hi Kevin,

Its a negligible ping loss, and ICMP traffic is generally given the lowest priority. Are you facing any network issues ?

And when you lost the power did any stack reboot itself ?

Regards

Kushagra

[ohareka70]

Kushagra,

Yes the stack did reboot itself when the power came back on. 

1) 99% of the 1000 users aren't complaining but some are saying the cant access network drives so I was thinking the two scenarios are related.

2) One of the monitoring servers which sits on the dmz is dropping pings to the servers on the LAN

but not all the time.  It only happened after the power drop

So - do you think that some lost pings might not really be a problem.  Maybe I am looking for an issue that doesn't exist.

thanks

Kevin

[Kushagra Kaushik]

so i believe Kevin at the time when stack rebooted itself , the STP would have reconverged .

Now to say you are still having some connectivity issues, check that by pinging from the affected hosts to the servers they are not able to rightly access.

Check if they are also facing ping drops.

Regards

Kushagra

[ohareka70]

Kushagra,

STP is ok - but their is some dropped pings to the server if you throw say 10000 pings at it.  I did a show int on the specifc fibre links - I am guessing CRC means their is a cable problem because none of the other 5 links are showing CRC issues

Fibre Link from Site 1 to Site 2            Sw-Site1L3-01#sh int Gi2/0/28

MTU 9000 bytes, BW 1000000 Kbit, DLY 10 usec, reliability 255/255, txload 4/255, rxload 2/255

51 input errors, 49 CRC, 0 frame, 0 overrun, 0 ignored

[Kushagra Kaushik]

Hey ya , please try changing the cable first and if its a fiber link try changing SFP(s) if changing fiber does not help.

Regards

Kushagra