**	$Filename: spar.txt $
**	$Revision: 37.2 $
**	$Date: 93/12/17 22:04:31 $


	The spar.device is a Sana-II PARnet device driver. It acts globally
	as any regular Ethernet driver, but has some limitations.

        The WireType for Spar is defined as Ethernet:

#define S2WireType_Ethernet             1


ios2_DataLength:
	Valid lengths for PARnet packets are the same as those defined for
        ethernet. From 64 up to 1500 bytes of data. 

Address format:
	The format for PARnet are made ethernet-alike, but it does not
	support any broadcast/multicast addresses. Broadcast is only
	accepted on ARP packets and when using the point-to-point mode.
	The standard for expressing ethernet addresses is as 6 bytes
	(octets) in the order in which the bytes are transmitted with the
	low-order bits in a byte transmitted first. Internally PARnet uses
	only one byte for addressing, this byte is taken from the first
	(0th) byte of the ethernet address. 

	Ethernet addresses in a Sana2IOReq occupy the first 6 bytes of
	an address field in transmission order with the low-order bits in
	a byte transmitted first.

Station Address:
	Each PARnet unit must have a unique hardware address. Since it has
        no built-in (ROM) address, it must be assigned using the
	ENV:Sana2/sparX.config file, where X representing the spar.device
        unit number.

Raw reads and writes:
	1 bytes of destination address,
	1 bytes of source address,
	2 bytes of type,
	64 to 1500 bytes of data
	(Internally converted to PARnet packets, which can not be seen by
	 the user)

Multicast:	Not supported

Broadcast:	Only supported when sending ARP packets, or when using the
		point-to-point mode by filling in the DSTADDR field in the
		ENV:Sana2/sparX.config file.

Promiscuous:	Not Supported

Packet Type Numbers:
	These are the same as those for Ethernet. Ethernet packet type
	numbers are assigned by:

	Xerox Corporation
	Xerox Systems Institute
	475 Oakmead Parkway, Sunnyvale, CA 94086
	Attn: Ms. Fonda Pallone
	(408) 737-4652


Some Common Packet Type Numbers:

      decimal  Hex        Description
      -------  ---        -----------
         000   0000-05DC  IEEE 802.3 Length Field
        2048   0800       TCP/IP -- IP
        2054   0806       TCP/IP -- ARP
       32821   8035       TCP/IP -- RARP
       32923   809B       Appletalk
       33011   80F3       AppleTalk AARP (Kinetics)
       33100   814C       SNMP
       33079   8137-8138  Novell, Inc.