Novell NETWARE 6-DOCUMENTATION Manual page 1726

Sending nodes always set the Transport Control field to zero when
building an IPX packet. When a router receives a packet that requires
further routing, it increments this field by one and forwards the packet.
Packet Type —Type of service offered or required by the packet.
Novell currently uses the packet types listed in
Table 1 Packet Types
Packet Type
NLSP
Routing information
Service advertising
Sequenced
NCP
Propagated
Destination Network —Number of the network to which the destination
node is attached.
When a sending node sets this field to 0x0 (that is, 0x00000000), the
destination node is assumed to be on the same network segment as the
sending (or source) node.
A special case exists when a workstation sends SAP Get Nearest Server
and RIP Get Local Target (or Route Request) broadcast requests at
initialization time. Because the workstation does not yet know which
network it belongs to, it sets both the Source Network and Destination
Network fields to 0 for these requests. When a router receives one of these
requests, it sends a reply directly to the sending workstation, filling in the
Source Network and Destination Network fields with the appropriate
network numbers.
NOTE:
In addition to network number 0, the numbers 0xFFFFFFFF and
0xFFFFFFFE are reserved for specific purposes. For this reason, they
should not be assigned to any IPX network. For more information about
Field Value (Hex)
0x00
0x01
0x04
0x05
0x11
0x14
IPX does not have a broadcast network number (such as 0xFFFFFFFF).
Table 1.
Purpose
NLSP packets
RIP packets
SAP packets
SPX packets
NCP packets
NetBIOS and other
propagated packets
Understanding
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