Applies only to X25 PVCs and X25 DLM circuits. Specifies the maximum
 window size allowed for the X25 circuit - that is, the maximum number
 of packets for which outstanding acknowledgments are allowed. Specify
 a value in the range 1 to 127.

 By default window size takes the value specified by the PROFILE
 parameter of the SET or DEFINE MODULE X25-PROTOCOL command.