Steps and tools to use to diagnose and troubleshoot packet loss and latency issues

Posted on 2014-12-19
Last Modified: 2016-10-28
Hi, Can anybody provide informative steps and tools that can be used in order to diagnose and troubleshoot packet loss and latency issues on a local VoIP LAN with two subnets and five Cisco SG300 non-stackable switches (four of them daisy-chained together) ?  The VoIP LAN is experiencing packet loss and latency issues with calls sounding 'robotic' and dropping being the symptoms.  Wireshark has been run on certain ports but there is not yet a comprehensive way to get a broader look into the overall network and LAN-wide traffic flow.  It is uncertain as to whether the problem is with the cabling, with the switches, or in another area.  The carrier has tested the outgoing lines and not found any issues with them so the issies seem to originate from the internal LAN. TIA for any help on this including listing some good troubleshooting and diagnostic tools, how to use them, commands to run on the Cisco switches to check for utilization and PPS, troubleshooting steps to try in order to isolate problems, etc...,
Question by:LGroup1
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
LVL 39

Expert Comment

by:Aaron Tomosky
ID: 40510926
Do you have snmp setup? Usually having a receiver for those will allow you to see the errors as they happen in the switches

Author Comment

ID: 40510929
I do not believe SNMP is currently setup or being used,
LVL 39

Accepted Solution

Aaron Tomosky earned 250 total points
ID: 40510959
If you don't use anything now, here is my suggestion:
1. Install this
2. Pick a SNMPv2 community string (password)
3. Setup all your switches with this community string and the ip of the paessler install.
LVL 22

Assisted Solution

eeRoot earned 250 total points
ID: 40510985
What model of IP phone are you using.  Many of the newer models have built in network stats and diagnostics.  Basic commands like ping, pathping, and tracert are useful starting points.  And Jperf can used to test a variety of tcp and udp settings.  Since you mention VoIP as the main issue, I also suggest you verify that you have the correct QOS settings on the switches user ports and uplink ports.

Author Closing Comment

ID: 40513904
Thanks all !   Are there also certain Cisco commands that are useful in determining PPS, dropped packets (from queues for example), latency, congestion, etc...    ?
LVL 39

Expert Comment

by:Aaron Tomosky
ID: 40513926
I believe that "show interface counters" should give a summary. Then you can add the interface name for details.

Author Comment

ID: 40521705
Okay, sounds good, thanks,
Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Lync - CUCM Integration Question 2 70
Switch ports not working 8 96
802.1x and RDP Issues 6 108
VMware:  Virtual switches and multiple NICs 9 123
Online collaboration is quickly becoming embedded in the workplace, and its benefits are tangible. See what the current landscape looks like and what the future holds for collaboration tools and the future of work.
The advancement in technology has been a great source of betterment and empowerment for the human race, Nevertheless, this is not to say that technology doesn’t have any problems. We are bombarded with constant distractions, whether as an overload o…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor ( If you're looking for how to monitor bandwidth using netflow or packet s…
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor ( If you're interested in additional methods for monitoring bandwidt…

738 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question