TCP Window Scale Option


Allows TCP systems to
discover that both implement the option
specify that all window values
should be multiplied by a power of two

Limited to 2^14
So, max window is (64K - 1) * 2^14  ~=  1GB
Thus max of 1/4 of the entire window space

If both TCPs send wscale option, window scaling protocol is used
Each TCP indicates how much its window should be scaled

If either does not send option
No window scaling
In either direction