PAM Programming Manual

Link-Level Interfaces
PAM Programming Manual—142482
3-9
Formatting an Aggregate SDU and an SDU Header
(Ethernet)
The aggregate SDU header begins at the first word of the aggregate SDU buffer,
followed directly by the initial SDU header. This primitive passes back to the
application an offset, in bytes, from the beginning of the aggregate SDU buffer to the
location where the user data begins.
The syntax for this primitive is
The parameters for this primitive are defined as follows:
Aggr^SDU^Buff^ptr (STRING .EXT)
Required input used to reference the buffer to be used for the aggregate SDU to the
L2S Formatting Library.
Aggr^SDU^Buff^Size^B (INT)
Required input that tells the L2S Formatting Library the size, in bytes, of the buffer
to be used for the aggregate SDU.
L2S^Type (INT)
Required input (Port^Type value) that is used to determine how link service access
points (LSAPs) are interpreted and what type of SDU header to generate. Currently
defined values for this parameter are
ZPAM^Val^Port^Type^Enet (DIX Ethernet, not IEEE 802.3)
ZPAM^Val^Port^Type^LLC1
For backward compatibility with TLAM applications these literals have the same
value as ZLAM^Val^Port^Type^Enet and ZLAM^Val^Port^Type^LLC1.
For C programs replace the caret (^) with an underscore ( _ ).
L2S^SDU^Type (INT)
The ZL2S^Val^SDU^Type identifier is a required input that declares the kind of
SDU the application wishes to generate. The valid values for this parameter are:
ZL2S^Val^SDUType^UI
ZL2S^Val^SDUType^Test
ZL2S^Val^SDUType^XID
INT PROC ZL2S^Frmt^Aggr^SDU^n^SDU^Hdr^
( Aggr^SDU^Buff^ptr
,Aggr^SDU^Buff^Size^B
,L2S^Type
,L2S^SDU^Type
,P^F^Flag
,Rsp^Flag,
,Foreign^Addr^ptr
,SDU^User^Data^Offset^B
,SDU^User^Data^Size^B
,Service^Class ) EXTENSIBLE;