TCP verification

[Hongbo Liu <hongbol@dimacs.rutgers.edu>]

After reading the basic validation tests of TCP which appears in the 
document "Simulator Tests"(ftp://ftp.ee.lbl.gov/papers/simtests.ps.Z), 
I have some questions about the trace result.

1. In the second test of Tahoe TCP about fast retransmit with many packets
   dropped , there are 2 or more pakcets were retransmitted in a row. 
   As I know, basic TCP will retransmit one packet each time. Retransmiting
   more than one packet seems to improve the performance of TCP. Which
   RFC do it conform?

2. In the test of reno TCP fast recovery with a single packet drop in 
   figure 13, it seems to have 3 connections, only the third one have 
   fast recovery. What's the effect of the first two connections? Why 
   did the document say they were used to get desired pattern for the 
   3rd connection. Could anyone give me more detailed information about 
   it? 

Thanks in advance.