OSI Layer 3: Routed and Routing Protocols
73
Novell NetWare Protocols
NetWare differs from the previous protocols because it is a network operat-
ing system and not a routing protocol. The basis of a network operating sys-
tem is a hierarchy of clients and servers: clients request services and
information from servers.
NetWare uses the top five layers of the OSI model to run the network
operating system. It uses proprietary protocols that fulfill the respective OSI
layer requirements. Figure 2.20 shows the relationship between the OSI lay-
ers and Novell NetWare's use of the upper five layers.
F I G U R E 2 . 2 0
OSI to NetWare comparison
Because the upper five layers are proprietary to Novell, they must use spe-
cial mappings to use the lower layers of the OSI model. To gain access to
Layer 2, NetWare uses Ethernet/IEEE 802.3 or Token Ring/IEEE 802.5,
FDDI, ARCnet, and PPP over WAN links.
IPX Packet Structure
Internetwork Packet Exchange (IPX) is Novell's equivalent for Layers 3 and
4 of the OSI model. Look at Figure 2.21 to get a picture of the IPX packet
structure. Following is an EtherPeek analysis of an IPX packet, which gives
you the information you need to define the packet structure:
IPX - NetWare Protocol
Checksum: 0xffff
Length: 73
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