A Quick Note About Tool Placement - Latency vs Retransmissions
Here's me chatting about this article with the guys at LMTV
http://www.lovemytool.com/blog/2015/0...
When troubleshooting performance issues most analysts find themselves chasing one of two issues; latency or retransmissions. Both scenarios result in performance degradation but have different root causes and solutions.
In this video I cover how the same problem can look like a latency or a retransmission related issue simply by changing your location in the network. I’ve been involved in many troubleshooting exercises where I get a totally different perspective by changing my test point.
Here are some additional tips when trying to identify if the issue is latency or retransmission related:
• Try to monitor from the senders perspective. If the sender is not physically close, then make yourself the sender by uploading a file or running iperf.
• Pay attention to your protocols. This article and video is helpful when dealing with TCP base protocols. UDP is a totally different animal.
• Try to leverage operating system commands like netstat –s to identify retransmissions.
• Understand what your tools are reporting. For example Wireshark might note a Retransmission, Spurious Retransmission, Fast Retransmission as well as other notes.
• Look for TCP specific hints like Selective Right Edge (SRE) or Selective Left Edge (SLE) to possibly indicate packet loss.
There is no guaranteed tip or trick when troubleshooting packet loss or latency issues but I hope this article and video will help you when troubleshooting.
Watch video A Quick Note About Tool Placement - Latency vs Retransmissions online, duration hours minute second in high quality that is uploaded to the channel The Technology Firm 29 August 2015. Share the link to the video on social media so that your subscribers and friends will also watch this video. This video clip has been viewed 2,398 times and liked it 5 visitors.
