3Com 2500 Switch User Manual


 
6-6 CHAPTER 6: ROUTING WITH IPX
IPX Packet Delivery On a NetWare network, the successful delivery of a packet depends both on
the proper addressing of the packet and on the internetwork configuration.
Packet addressing is handled in the packet’s Media Access Control (MAC)
protocol header and IPX header address fields.
To send a packet to another node, the sending node must know the
complete internetwork address including the network, node, and socket of
the destination node. Once the sending node has the destination node’s
address, it can proceed with addressing the packet. However, the way the
MAC header of that packet is addressed depends on whether the sending
and destination nodes are separated by a router. See Figure 6-3.
Figure 6-3 IPX Packet Routing
Sending Node’s Responsibility
When a node needs to send information to another node with the same
network number, the sending node can simply address and send packets
directly to the destination node. However, if the sending and receiving
nodes have different network numbers, the sending node must find a
router on its own network segment that can forward packets to the
destination node’s network segment.
Network = 000000AA
Node = 000000000001
Socket = 4003
Node Node
000000000020 000000000021
Network = 000000BB
Node = 000000000003
Socket = 0451
MAC Header
Destination Node = 000000000020
Source Node = 000000000001
IPX Header
Checksum = FFFF
Packet Length = 011E
Tranport Control = 00
Packet Type = 11
Dest Network = 000000BB
Dest Node = 000000000003
Dest Socket = 0451
Source Network = 000000AA
Source Node = 000000000001
Source Socket = 4003
Data
MAC Header
Destination Node = 000000000003
Source Node = 000000000021
IPX Header
Checksum = FFFF
Packet Length = 011E
Tranport Control = 01
Packet Type = 11
Dest Network = 000000BB
Dest Node = 000000000003
Dest Socket = 0451
Source Network = 000000AA
Source Node = 000000000001
Source Socket = 4003
Data
Sending Node Router Destination Node