TCP window size

Is there a way of changing the TCP window size on the MK.

I am running BGP between a MK and a Cisco and there is a big difference in the TCP window size

sndwnd: = the remote peers TCP window size.
rcvwnd: = The local peers TCP window size


iss: 2599123019 snduna: 2599145470 sndnxt: 2599145470 sndwnd: 5840
irs: 2109489265 rcvnxt: 2109511773 rcvwnd: 64984 delrcvwnd: 551

Cheers

Anthony