[[Include(WikiToC)]]

== Measuring Network Performance ==
This wiki page contains the tutorial of measuring network performance.

Authors:

Artur Minakhmetov, Telecom Paris : artur.minakhmetov[at]telecom-paris.fr\\
Michael Sherman, Rutgers University : msherman[at]winlab.rutgers.edu


Last Updated: 26 June 2019 

----
= Description =
Cosmos test-bed provides a set of different network interfaces with different speed and rates. In this tutorial we will show how to measure the network performance. 

----

= Context =

This tutorial is based on topology and settings described in the [wiki:tutorials/optical-network-example optical network tutorial].

This example includes a server ''srv4-lg1'' with connected to it ''tengigabitethernet 1/34'' and joined with ''twentyFiveGigE 1/1/4'' on ''vlan 124''. Binding ''tengigabitethernet 1/32'' with ''twentyFiveGigE 1/1/4'' is performed the same way as in the optical network tutorial. 

The server ''srv4-lg1'' has an IP address assigned to it 192.168.1.4 on ''eno1'' interface.

For simplicity, the Calient Switch S320 connects ''tengigabitethernet 1/34'' with ''tengigabitethernet 1/32/1'' through direct optical connection: ''5.7.4<-->5.7.6''

----

= Measurement =

Measurements are preformed through a command line tool ''iperf''. Examples and descriptions of its operation could be found [https://fasterdata.es.net/performance-testing/network-troubleshooting-tools/iperf/ here].

* Set ''srv1-lg1'' as a server:

{{{#!shell-session
native@srv1-lg1:~$ iperf -s   
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
}}}

* Set ''srv4-lg1'' as a client with sending traffic to ''srv1-lg1'':


{{{#!shell-session
native@srv4-lg1:~$ iperf -c 192.168.1.1   
------------------------------------------------------------
Client connecting to 192.168.1.1, TCP port 5001
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  3] local 192.168.1.4 port 35486 connected with 192.168.1.1 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  11.0 GBytes  9.42 Gbits/sec
}}}

* This measurement shows that the it's possible to have **9.42 Gbits/sec** of bandwidth. 

* Previous measurement creates a ''TCP'' connection. In order to test ''UDP'' traffic, a bitrate of ''UDP'' traffic has to be specified through and option ''-b''. UDP traffic is specified through an option ''-u''. Results of ''UDP'' traffic test are below :

Server side:
{{{#!shell-session
native@srv1-lg1:~$ iperf -s -u
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size:  208 KByte (default)
------------------------------------------------------------
}}}

Client side:
{{{#!shell-session
native@srv4-lg1:~$ iperf -c 192.168.1.1 -u -b 9gbps
------------------------------------------------------------
Client connecting to 192.168.1.1, UDP port 5001
Sending 1470 byte datagrams, IPG target: 1.31 us (kalman adjust)
UDP buffer size:  208 KByte (default)
------------------------------------------------------------
[  3] local 192.168.1.4 port 33737 connected with 192.168.1.1 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  9.77 GBytes  8.39 Gbits/sec
[  3] Sent 7134255 datagrams
[  3] Server Report:
[  3]  0.0-10.0 sec  9.30 GBytes  7.99 Gbits/sec   0.000 ms 342498/7134255 (0%)
}}}

* UDP traffic measurements show possible bandwidth of **7.99 Gbits/sec**. This result could be ameliorated through specific settings potentially.

----

= Conclusion =

In this tutorial we showed how it's possible to measure network performance and verify 10Gbit possibilities of optical transceivers achieving **9.42 Gbits/sec** for ''TCP'' traffic and **7.99 Gbits/sec** for ''UDP'' traffic.