06-10-2020 12:20 AM
Hi, experts,
Intermittent packet loss ( request timed out ) is found when I do ping test between two Cisco devices (one is Cat3850-Sw01, another is unknown Cisco device-Sw02).
Temporarily, the following results are found during the ping test (from Sw01 to Sw02):
1. no packet loss with 64bytes to 500bytes packet size
2. packet loss with larger than 500bytes packet size, says 800, 1000...1500bytes
3. no any error from switches interfaces ( as the following captured - for both switches )
Any advice or recommendation, many thanks in advance.
Solved! Go to Solution.
06-10-2020 10:34 AM
Hi,
The issue could be related to the storm-control commands you have under the interface. So, for testing please remove these commands and run the ping test again.
storm-control broadcast level bps 10m
storm-control multicast level bps 10m
storm-control unicast level bps 600m
storm-control action shutdown
storm-control action trap
HTH
06-10-2020 03:05 AM
Hi,
Are you facing any service slowness issue?
We need more information as to What is QoS configuration on Sw02 (If any), MTU size, CPU utilization, etc.
06-10-2020 07:01 AM - edited 06-10-2020 07:11 AM
Hi, Deepak Kumar,
Thanks for your quick reply,
Sw01 interface connects to Sw02 interface in the same VLAN, no hop/route between these two interfaces.
The switches are configured with default setting, default MTU = 1500, CPU utilization is always under 30%, no QoS and no policy-map configuration, FIFO is default..
In fact, the switches configurations are simple, and no resilient network configuration, and
1. Ping response time (rtt, latency ) is not felt slow, for example, rtt < 150ms
2. Network service does not fell slow
With regards
06-10-2020 08:00 AM
Hi.
The output of the interface looks clean. Can you post the output of "sh run" from both switches?
Also, is this the command you are using to test?
ping <ip address> size 1500 df-bit
HTH
06-10-2020 09:27 AM - edited 06-10-2020 09:30 AM
Hi, Reza Sharifi,
I tried the extended ping with "df" set or not set, but the result is same packet loss (not many, just 1 or 2% packet loss when the packet size > 500bytes ).
The following configuration is our switch interface ( the second line/resilient line is unplugged at pingtest, so no spanning tree is needed to be concerned ):
interface GigabitEthernet1/0/18
description To_HF_VL888-9__500Mb_line_01
switchport trunk allowed vlan 888-890
switchport mode trunk
storm-control broadcast level bps 10m
storm-control multicast level bps 10m
storm-control unicast level bps 600m
storm-control action shutdown
storm-control action trap
spanning-tree vlan 888-889 port-priority 144
spanning-tree vlan 888-889 cost 3
!
The opposite switch is not ours, configuration can not be seen. but these two switches are connected with 10m UTP cable.
with many thanks
06-10-2020 10:34 AM
Hi,
The issue could be related to the storm-control commands you have under the interface. So, for testing please remove these commands and run the ping test again.
storm-control broadcast level bps 10m
storm-control multicast level bps 10m
storm-control unicast level bps 600m
storm-control action shutdown
storm-control action trap
HTH
06-10-2020 07:14 PM
Great, the problem of packet loss is due to the configuration of the storm-control.
Great thanks of your guys, cheers
06-10-2020 08:00 PM
Glad to help
Good Luck!
06-10-2020 10:02 AM
Hi friend,
Well sounds really strange, i think maybe you have a problem about tcp adjust-mss. Try to check this part and define de max size of a packet and check if in both devices are equal. i copy a link to more info about this topic.
Hope find the problem and solve the problem.
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