[sdnog] Latency test

[Philip Paeps]

On 2018-01-29 09:21:27 (+0100), Samir Abdullatif wrote:
> Can you point me to a good and reliable tool which I can use to 
> measure latency.
> I have two links, one passing through a proxy and the other is 
> bypassing the proxy.
> My requirement is to have some sort of measurement on how much delay 
> the proxy adds in my network.

Depending on the protocol, you might be able to use mtr 
(http://www.bitwizard.nl/mtr/).  It's really only good for ICMP and UDP 
though.  It has basic support for TCP but it's probably too basic for 
any real-world use.

tcpdump can compare the end-to-end latency for you but it can't (by 
itself) tell you the latency per hop.

What protocol are you trying to measure?  "Proxy" makes it sound like 
HTTP.  If it's HTTP, Apache Bench 
(https://httpd.apache.org/docs/2.4/programs/ab.html) might help.  It 
primarily wants to test the response latency of HTTP servers rather than 
the path but ... it can give you a rough indication of the path latency 
if rough is good enough.  Like tcpdump, it can't tell you exactly where 
the latency is picked up though.

Philip

-- 
Philip Paeps
Senior Reality Engineer
Ministry of Information