INT 61 - PCIBM PC/TCP(Transmission Control Protocol) A higher level (session layer) of the TCP/IP protocol suite.  See also IP, TCP/IP. kernel v2.05+ - "get_option" - GET OPTIONS APPLIED TO NET DESCR
	AH = 21h
	BX = network descriptor
	CX = length of buffer
	DS:DX -> buffer for return values
	SI = 0004h (ignored by v2.2-)
	DI = option (see #03468)
Return: CF clear if successful
	    DS:DX -> value (usually 32 bits) returned by selected option
	CF set on error
	    AX = error code (see #03319 at INT 61"FTP(File Transfer Protocol)  The standard protocol for copying files from one machine to another on a TCP/IP (Internet) network.  Also the program of the same name with which a user may transfer files. Software")
Notes:	this function is not supported by Beame&Whiteside's BWPCTCP v3.0a shim
	v2.11 reportedly stores the actual 32-bit value of an option in DS:DX
	  rather than using a buffer in memory
SeeAlso: INT 61"FTP(File Transfer Protocol)  The standard protocol for copying files from one machine to another on a TCP/IP (Internet) network.  Also the program of the same name with which a user may transfer files. Software",INT 61/AH=00h"PCIBM PC/TCP(Transmission Control Protocol) A higher level (session layer) of the TCP/IP protocol suite.  See also IP, TCP/IP.",INT 61/AH=20h