Details on TCP implementation

[Preethi Natarajan]

Hello,

I am trying to understand the following details about TCP implementation 
in FreeBSD (6.1).

- The sack.enable sysctl turns on SACK options (RFC2018)?
- Does the implementation leverage SACK information for retransmissions 
(RFC3517)?
- Is Appropriate Byte Counting (ABC) available (RFC3465) now/in the future?


Thanks a ton!
Preethi