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Topology

Setup

Download the archive and unpack it

wget http:///session6.zip
unzip session6.zip

The archive contains the follosing files

  • ubuntu.img - the virtual machine's disk
  • prepare.sh - the script for setting up the virtual machine
  • iperf_client.sh - launches multiple streams using iperf
  • iperf_server.sh - listens on multiple sockets using iperf

Install the necessary packets

sudo ./prepare.sh prepare

Boot up the virtual machine

sudo ./prepare.sh start

Open SSH consoles to the virtual machine

ssh root@192.168.0.2

Bandwidth

netperf

Run a simple netperf test

netperf -H 192.168.0.2
  • What is the bandwidth of the virtual link?
  • How does netperf run? On the virtual machine, check the TCP listening ports
    netstat -tlpn

    Which options are available to the netperf users?

    netperf --help

    The user can choose from a series of tests. Which are them?

    man netperf

    Run a TCP stream test. Now, the virtual machine should be the sender and the host the receiver. Compare the CPU load of the sender and the receiver.

    netperf -H 192.168.0.2 -t TCP_MAERTS -cC

Speedtest.net

Measure bandwidth and delay on links towards California and Spain

http://speedtest.net

Latency

ping

Ping the following hosts

192.168.0.2
cs.curs.pub.ro
gnu.org

Compare the latencies and verify the number of hops along each way using traceroute.

netperf

Run a 2 seconds UDP request-response test and display the CPU usage for both the host and the virtual machine

netperf -H 192.168.0.2 -t UDP_RR -l 2 -cC

How many request-responses have been issued ?

DNS latency

Browse the Web for a few random pages. Do you find the response time acceptable? What does a browser do when you type a web page's address? Which DNS server are you using? Try resolving a random hostname. What is the query time?

dig ampathos.ro

Edit /etc/resolv.conf to use Google's DNS instead of your ISP's DNS. Add the following line at the top of the file.

nameserver 8.8.8.8

Try resolving ampathos.ro again. Is the query time better? Surf the web. Is the lag significant? Revert your nameserver changes.

UDP and TCP

What is the MTU of the br0 link?

ip link sh dev br0

Measure the UDP bandwidth using the default send size (MTU). Display the UDP statistics before and after running the test for the host interface.

netperf -H 192.168.0.2 -t UDP_STREAM -l 1 -cC

Repeat the test sending 64-byte packets.

netperf -H 192.168.0.2 -t UDP_STREAM -l 1 -cC -- -m 64

The throughput is obviously worse and the CPU load is higher. Why?

netperf

Availability

ethtool

MTU

sesiuni/virtualization-networking/session6.1372206991.txt.gz · Last modified: 2013/06/26 03:36 by freescale