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IPX Addressing and Routing 299

Internal Networks and Encapsulation Types

Cisco requires that CCNAs understand encapsulation, particularly with IPX. It is always
Cisco's desire that the professional certifications prove that the candidate knows how to make
networks that work rather than to certify individuals who are willing to memorize just for the
sake of passing the test. However, IPX encapsulation is one area in which memorization is
important once the base concepts are understood. Table 5-32, later in this section, lists several
terms you should remember.

Encapsulation is best understood in the context of two additional and important concepts
related to routing, as seen using Figure 5-34. NetWare servers use internal network numbers.
Also, clients, servers, and routers all must be configured to use the correct encapsulation.
Routing will also be reviewed using the same figure.

Figure 5-34

Sample IPX Network 1

Client 1 has already logged in to Server 1 and is busily sending packets. Because NetWare
servers use an internal network number, the destination of packets from Client 1 to Server 1 is
1000.0000.0000.0001. The source address of these packets is Client 1's IPX address

Network 4

Network 3

Server 1

3.11

4.0

Network 2

Network 1

S0 R3

Client 1

Client 2

Server 2

Eth

IPX

Data

Destination is 1000.0000.0000.0001

Source is 1.0200.1111.1111

Server 1 internal net 1000
Server 2 internal net 1001
Server 1 MAC 0200.AAAA.AAAA
Server 2 MAC 0200.BBBB.BBBB

ch05.fm Page 299 Monday, March 20, 2000 5:06 PM