Why I am seeing multiple syn packets when I open a web page?

Question

Hi Trying to find an explanation for a slow network response, I installed the wireshark sniffer. When I opened a web page I see that multiple syn packets are being sent to the web server, in less tan 0.005 seconds. Any idea why this happens ? alt text

Answer 1

This is because your browser wants to have multiple parallel sessions to the server to speed up communication. In your case 6 sessions are started right away - I think this is the default for Chrome In Mozilla you can control this in about:config

Regards Matthias

From http://tools.ietf.org/html/draft-ietf-tcpm-initcwnd-00

   In the mean time, applications have responded to TCP's "slow" start.
   Web sites use multiple sub-domains [Bel10] to circumvent HTTP 1.1
   regulation on two connections per physical host [RFC2616]. As of
   today, major web browsers open multiple connections to the same site
   (up to six connections per domain [Ste08] and the number is growing).
   This trend is to remedy HTTP serialized download to achieve
   parallelism and higher performance.