High latency issue in LAN - between two switches.

[bimalnp4me]

HI

PC -> core SW(6500) -> fiberswitch -> fiberSW - > core SW(4500) -> ------- ping time < 1ms

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Reply from 10.10.3.7: bytes=32 time=1ms TTL=254

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Reply from 10.10.3.7: bytes=32 time<1ms TTL=254

Ping statistics for 10.10.3.7:
    Packets: Sent = 927, Received = 927, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 196ms, Average = 0ms

PC -> core SW(6500) -> fiberswitch -> fiberSW - > core SW(4500) -> Desk Switch (2960) ---- ping time is very inconsistent

Reply from 10.10.3.93: bytes=32 time=4ms TTL=254

Reply from 10.10.3.93: bytes=32 time=5ms TTL=254

Reply from 10.10.3.93: bytes=32 time=4ms TTL=254

Reply from 10.10.3.93: bytes=32 time=17ms TTL=254 -----------------------

Reply from 10.10.3.93: bytes=32 time=5ms TTL=254

Reply from 10.10.3.93: bytes=32 time=4ms TTL=254

Reply from 10.10.3.93: bytes=32 time=5ms TTL=254

Reply from 10.10.3.93: bytes=32 time=72ms TTL=254 --------------------------

Reply from 10.10.3.93: bytes=32 time=6ms TTL=254

Reply from 10.10.3.93: bytes=32 time=4ms TTL=254

Reply from 10.10.3.93: bytes=32 time=7ms TTL=254

Reply from 10.10.3.93: bytes=32 time=4ms TTL=254

Reply from 10.10.3.93: bytes=32 time=4ms TTL=254

Reply from 10.10.3.93: bytes=32 time=11ms TTL=254 -----------------------

Reply from 10.10.3.93: bytes=32 time=4ms TTL=254

Reply from 10.10.3.93: bytes=32 time=4ms TTL=254

Reply from 10.10.3.93: bytes=32 time=6ms TTL=254

Ping statistics for 10.10.3.93:
    Packets: Sent = 2076, Received = 2062, Lost = 14 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 3ms, Maximum = 160ms, Average = 7ms

can enyone help me to troubleshoot this issue.. some times it even conectivity get lost..

[Bilal Nawaz]

It's the 4500 right?

Sent from Cisco Technical Support iPhone App

[Bilal Nawaz]

Hello. You have gigabit ports running at 100mb?
I noticed this on the core:
Total output drops: 17120466

And also noticed that flow control is unsupported on the warehouse switch
Or is that one of those 'cosmetic bugs'

Configuring IEEE 802.3x Flow Control
Flow control enables connected Ethernet ports to control traffic rates during congestion by allowing congested nodes to pause link operation at the other end. If one port experiences congestion and cannot receive any more traffic, it notifies the other port by sending a pause frame to stop sending until the condition clears. Upon receipt of a pause frame, the sending device stops sending any data packets, which prevents any loss of data packets during the congestion period.

Could you kindly do this for me, maybe out of hours or whenever it doesn't effect your users etc...

On both interfaces do these commands

Shut
Speed 1000
Duplex full
No shut

At least try to get this to operate at gigabit speeds for now.

See of you can enable flow control on both your switch.

http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_55_se/configuration/guide/swint.html#wp2071785

Hope this helps

Sent from Cisco Technical Support iPhone App

[bimalnp4me]

Thanks bilal..

i will check this... and update you guys..

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Just to clarify.  Are you saying you see erratic ping times to a 2960 switch's management IP?  Are ping times to hosts through the same device okay?  If so, network devices give priority to forwarding traffic, not responding to pings.  I.e., network device ping times can be erratic when the switch is functioning fine.  Later devices support a special SLA responder, which will note the time ping request arrives, and the time before the device replies.  This allows the ping requestor to discount most device latency providing a much better measure of network latency.