Understanding the network.pdf - Back to Home

Figure 3.11. Novell (IPX) protocol suite.
• Layer 0, the transmission media layer, is responsible for data exchange
between the end-node and the transmission media.
• Layer 1, the Internet layer, provides a data exchange facility between
end-nodes connected on different networks.
• Layer 2, the transport layer, handles end-to-end communication between
end-nodes.
• Layer 3, the control layer, provides session control and data presentation
services.
• Layer 4, the application layer, manages data semantics between client and
server interactions such as login, file, and print services.
Where TCP/IP and AppleTalk are unaware of Layer 2 (OSI-RM), IPX operates in
conjunction with it. The most obvious example of this symbiosis is the IPX's
end-node number. The IPX end-node number is the NIC's unique hardware address.
The other, slightly more complex dualism is IPX's use of hardware encapsulation.
IPX operates over several LAN and WAN transmission media formats, including
Ethernet, Token Ring, FDDI, and Point-to-Point Protocol (PPP). NetWare, in its
original form, supported a single proprietary encapsulation format. However, as
Layer 2 technologies evolved (just as with AppleTalk), IPX was adjusted to operate
with the new encapsulation formats, of which IPX supports several (see Table 3.2).