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network cable segment. It may sometimes be desirable for redundancy to have several seed routers on a segment. This is acceptable as long as all seed routers on the segment are seeding the same network number.
Service Advertising Protocol
Routers participate in allowing end nodes to access IPX services (such as file servers, print servers, communications servers, etc.) by keeping a list of all of the services on an IPX internetwork. This list is maintained by examining the Service Advertising Protocol (SAP) packets which are sent by servers and other routers on the local segment, and by rebroadcasting this information out of their other interfaces.
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Client Machine Addressing
Unlike TCP/IP, IPX workstations do not have fixed network/node addresses that need to be configured. Instead, a workstation gets its network number from the router(s) on the segment it is connected to, and uses its Ethernet address for its node number.
This means that an IPX workstation may have as much as 18 hexadecimal digits of network/node address. Fortunately for workstation users, the NetWare client software does the work of discovering the network number and setting the address. Users only need to install Novell drivers to be able to use the IPX protocols over their network.
Routers which support IPX can use any of four “frame types” to send IPX packets. Each frame type organizes the IPX information in a network packet (i.e. frame) in a slightly different fashion. Although the basic information may be the same, clients or servers using different frame types cannot communicate with each other without an intermediate translation occurring between frame types. This translation is called “transitional routing,” and is one of the functions that can be performed by routers.
The four IPX frame types are:
•Ethernet_Type_II
•Ethernet_802.3 (Raw)
•Ethernet_802.2
•Ethernet_SNAP
Older versions of NetWare defaulted to the 802.3 Raw frame type, whereas NetWare 4.0 uses the 802.2 frame type.
