ארכיון פוסטים מהחודש "ספטמבר, 2011"

TCP Throwput calculation and limitaiton

יום חמישי, 15 בספטמבר, 2011

TCP conneciton is limit by several factors such latency (Round-Trip-Delay) and Window Size,   

Window size is the maximum number of bytes that the sneder may allow to send without recieve an acknolege from the reciever,

since TCP is connection orinted protocl and error correction this type of behavior used to identify and avoid data coroptions due to packet lost

here are some intersting links i have found:

http://www.babinszki.com/Networking/Max-Ethernet-and-TCP-Throughput.html

http://www.speedguide.net/analyzer.php

http://www.speedguide.net/articles/the-tcp-window-latency-and-the-bandwidth-delay-2678

tcpdump examples

יום שני, 5 בספטמבר, 2011

tcpdump is a great tool for capturing traffic with a linux over the network,
before  making the capture make sure configure on the cisco router a monitor session with the following command example

monitor session 1 source int gig 7/1
monitor session 1 dest int gig 7/2

otherwise it wont work
(See this link for setting up SPAN port http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a008015c612.shtml)

After finsih with the SPAN port start enjoy tcpdump,

here is some necesery and good example for capture wimax R6 traffic with tcpdump

tcpdump 'udp port 2231' -i eth1 -w ~/pcap/pcap$TAG &

switches:

-i    interface to bind to

-w  save all packets to pcap file with wireshark format