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Saturday, December 28, 2013
 
Blast from the Past : The Weekend Playlist #3

The 80s contd.,

The 80s witnessed the rise of fine talent - so, it is only fitting to dedicate another complete playlist for the 80s. Here it is. Enjoy. Earlier playlists can be accessed from the following locations:

    Blast from the Past : The Weekend Playlist #2 (80s)
    Blast from the Past : The Weekend Playlist #1 (50s, 60s and 70s)

Audio-Visual material courtesy: YouTube

1. Aerosmith - Dude (Looks Like a Lady) (1987)

Featured in Robin Williams' Mrs. Doubtfire.

2. Kool & the Gang - Celebration (1980)

San Francisco Bay Area Star 101.3 audience must be hating this one.

3. Wham - Wake Me Up Before You Go-Go (1984)

That was George Michael before his solo career.

4. Toto - Rosanna (1982)

Grammy winner

5. Club Nouveau - Lean on Me (1987)

Cover version. Original by Bill Withers in 1972.

6. Tom Petty - Free Fallin' (1989)

Enjoy

7. Kenny Loggins - Footloose (1984)

Of course, it was featured in Kevin Bacon's Footloose

8. Simple Minds - Don't You (Forget About Me) (1985)

This is my brother, Vishu's, pick.

9. Fun Boy Three - Our Lips Are Sealed (1983)

Another cover. Original by The Go-Go's just two years earlier.

10. Men without Hats - The Safety Dance (1983)

S s s s A a a a F f f f E e e e T t t t Y y y y

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Saturday, December 21, 2013
 
Measuring Network Bandwidth Using iperf

iperf is a simple, open source tool to measure the network bandwidth. It can test TCP or UDP throughput. Tools like iperf are useful to check the performance of a network real quick, by comparing the achieved bandwidth with the expectation. The example in this blog post is from a Solaris system, but the instructions and testing methodology are applicable on all supported platforms including Linux.

Download the source code from iperf's home page, and build the iperf binary. Those running Solaris 10 or later, can download the pre-built binary (file size: 245K) from this location to give it a quick try (right click and "Save Link As .." or similar option).

Testing methodology:

iperf's network performance measurements are based on the client-server communication model - hence requires establishing both a server and a client. The same iperf binary can be used to run the process in server and client modes.

  1. Start iperf in server mode
    iperf -s -i <interval>

    Option -s or --server starts the process in server mode. -i or --interval is the sampling interval in seconds.

  2. Start iperf in client mode, and test the network connection between client and the server with arbitrary data transfers.

    iperf -n <bytes> -i <interval> -c <ServerIP>
    

    Option -c or --client starts the process in client mode. Option -n or --bytes specify the number of bytes to transmit in bytes, KB (use suffix K) or MB (use suffix M). -i or --interval is the sampling interval in seconds. The last option is the IP address or the hostname of the server to connect to. By default, client connects to the server using TCP. -u or --udp switches to UDP.

  3. Check the network link speed on server and client, and compare the throughput achieved.

Check the man page out for the full list of options supported by iperf in client and server modes.

Here is a simple demonstration.

On server node:

iperfserv% dladm show-phys net0
LINK              MEDIA                STATE      SPEED  DUPLEX    DEVICE
net0              Ethernet             up         1000   full      igb0

iperfserv% ifconfig net0 | grep inet
        inet 10.129.193.63 netmask ffffff00 broadcast 10.129.193.255

iperfserv% ./iperf -v
iperf version 3.0-BETA5 (28 March 2013)SunOS iperfserv 5.11 11.1 sun4v sparc sun4v


iperfserv% ./iperf -s -i 1
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------

On client node:

client% dladm show-phys net0
LINK              MEDIA                STATE      SPEED  DUPLEX    DEVICE
net0              Ethernet             up         1000   full      igb0

client% ifconfig net0 | grep inet
        inet 10.129.193.151 netmask ffffff00 broadcast 10.129.193.255

client% ./iperf  -n 1024M  -i 1 -c 10.129.193.63
Connecting to host 10.129.193.63, port 5201
[  4] local 10.129.193.151 port 63507 connected to 10.129.193.63 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.01   sec   105 MBytes   875 Mbits/sec
[  4]   1.01-2.02   sec   112 MBytes   934 Mbits/sec
[  4]   2.02-3.00   sec   110 MBytes   934 Mbits/sec
   [...]
[  4]   8.02-9.01   sec   110 MBytes   933 Mbits/sec
[  4]   9.01-9.27   sec  30.0 MBytes   934 Mbits/sec
[ ID] Interval           Transfer     Bandwidth
      Sent
[  4]   0.00-9.27   sec  1.00 GBytes   927 Mbits/sec
      Received
[  4]   0.00-9.27   sec  1.00 GBytes   927 Mbits/sec

iperf Done.

At the same time, somewhat similar messages are written to stdout on the server node.

iperfserv% ./iperf  -s -i 1
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------
Accepted connection from 10.129.193.151, port 33457
[  5] local 10.129.193.63 port 5201 connected to 10.129.193.151 port 63507
[ ID] Interval           Transfer     Bandwidth
[  5]   0.00-1.00   sec   104 MBytes   874 Mbits/sec
[  5]   1.00-2.00   sec   111 MBytes   934 Mbits/sec
[  5]   2.00-3.00   sec   111 MBytes   934 Mbits/sec
   [...]
[ ID] Interval           Transfer     Bandwidth
      Sent
[  5]   0.00-9.28   sec  1.00 GBytes   927 Mbits/sec
      Received
[  5]   0.00-9.28   sec  1.00 GBytes   927 Mbits/sec
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------

The link speed is specified in Mbps (megabit per second). In the above example, the network link is operating at 1000 Mbps speed, and the achieved bandwidth is 927 Mbps, which is 92.7% of the advertised bandwidth.

Notes:

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Saturday, December 07, 2013
 
Blast from the Past : The Weekend Playlist #2

The 80s

The quality of music steadily improved over the decades in mid-1900s, and eventually peaked in the 80s. Some may disagree, but in my opinion, the 80s were easily one of the best decades for music in the United States. The decade witnessed the emergence of many successful artists who delivered solid hits, that are still relevant and part of many pop culture references today. The launch of MTV in 1981 upped the ante to produce interesting videos in an effort to increase the global outreach.

In this iteration, let's focus on the decade of eighties. The following playlist has some random songs from the 80s in no particular order. The previous playlist can be accessed from this location:

    Blast from the Past : The Weekend Playlist #1 (50s, 60s and 70s)

Audio-Visual material courtesy: YouTube

1. INXS - Need You Tonight (1987)

Love the guitar riff.

2. Queen - I Want to Break Free (1984)

Featured in some of the Coke commercials in mid-2000s.

3. John Farnham - You're the Voice (1986)

Wasn't so popular in US, I believe. Great song nevertheless.

4. Phil Collins - Another Day in Paradise (1989)

Grammy winner.

5. Journey - Don't Stop Believin' (1981)

Very popular in pop culture.

6. Tears for Fears - Shout (1984)

#1 on the Billboard Hot 100 chart for 3 weeks.

7. Fine Young Cannibals - She Drives Me Crazy (1989)

Enjoy!

8. Mr Mister - Kyrie (1985)

Has 80s feel all over it.

9. Dream Academy - Life In A Northern Town (1985)

Expect to be hit with something unexpected @00:00:52s. Featured in one of the episodes of King of the Hill.

10. Robert Palmer - Addicted To Love (1986)

Who wouldn't like models in uniform fiddling with guitars and musical instruments.

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