Some ways to break TCP

http://blog.leith.ie/some-ways-to-break-tcp/


http://www.cis.syr.edu/~wedu/seed/Labs/Attacks_TCPIP/TCPIP.pdf

Also, it is useful to note the performance of TCP over LANs, over WANs and in general trends in TCP.
Here is one link about this:
http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_9-2/gigabit_tcp.html