linux - HTTP 1.1 Content-MD5 redundancy given TCP/IP Checksum? -

i wondering, in http 1.1 specifications, there field content-md5. however, since http ride atop tcp/ip in entire osi stack, , given tcp/ip has header checksum ensure data transmitted checked, curious why need content-md5 in http 1.1 specifications? did misunderstand or miss out something?

for http/1.1 header specs referred to:

http://www.w3.org/protocols/rfc2616/rfc2616-sec14.html#sec14.15

for tcp/ip specs referred section 3.1 at:

http://www.ietf.org/rfc/rfc791.txt

to me, adding content-md5 in http header, we're adding more work done @ server. why not use mechanisms tcp/ip provides?

cheers , in advance :)

the http content md5 value independently useful.

the tcp checksum pretty weak, , given amount of data transmitted on internet, quite there silent failures of tcp checksum value.

if care, however, want use stronger, tls.