Novell NETWARE 6, Руководство пользователя

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Understanding
21
Internetwork Packet Exchange
103-000176-001
August 29, 2001
Novell Confidential
Manual 99a
38
July 17, 2001
How IPX Routing Works
NetWare routers interconnect different IPX network segments and receive
instructions for addressing and routing packets between these segments from
the IPX protocol. IPX accomplishes these and other Network-layer tasks with
the help of RIP, SAP, and NLSP.
For more information about how IPX routing works, refer to:
Š When a Workstation Sends an IPX Packet
Š When a Router Receives an IPX Packet
Š When a Router Forwards an IPX Packet
When a Workstation Sends an IPX Packet
Consider a NetWare workstation that wants to send data to another
workstation. If both workstations share the same network number (both are on
the same segment), the sending workstation addresses and sends packets
directly to the destination workstation's physical address. If the two
workstations have different network numbers (each is on a different segment),
the sending workstation must first find a router on its own segment that can
forward packets to the segment on which the destination workstation resides.
To find this router, the sending workstation broadcasts a RIP packet requesting
the fastest route to the destination segment. The router on the sending segment
with the shortest path to the destination segment responds to the request. In its
response, the router includes its own network and node address in the IPX
header.
NOTE:
If the sending node is a router instead of a workstation, the router does not
need to broadcast a RIP request to obtain this information; the router obtains the
information from its internal routing table.
When the sending workstation knows the router node address, it addresses and
sends packets to the destination workstation as follows:
1. The sending workstation places the destination node IPX network
address—network, node, and socket numbers—in the corresponding
destination fields of the IPX header.
2. The sending workstation places its own IPX network address—network,
node, and socket numbers—in the corresponding source fields of the IPX
header. The sending workstation also fills out all other fields in the
header.