540 Chapter 8: WAN Protocols and Design
Figure 8-12
Partial Mesh with IP and IPX Addresses
Subinterfaces allow the Atlanta router to have three IP addresses and three IPX addresses
associated with its serial 0 interface. Subinterfaces can treat each VC as though it were a point-
to-point serial link. Each of the three subinterfaces of serial 0 on Atlanta would be assigned a
different IP address and IPX address from the list in Table 8-14. Example configurations follow
in the next section of this chapter.
The third case of Layer 3 addressing is a hybrid between the first two illustrated in Figure 8-11
and Figure 8-12. Consider Figure 8-13, which shows a trio of routers with VCs between each
of them, as well as two other VCs to remote sites.
Table 8-14
IP and IPX Addresses, with Point-to-Point Subinterfaces
Router
Subnet
IP Address
IPX Network
IPX Address
Atlanta
140.1.1.0/24
140.1.1.1
1
1.0200.aaaa.aaaa
Charlotte
140.1.1.0/24
140.1.1.2
1
1.0200.bbbb.bbbb
Atlanta
140.1.2.0/24
140.1.2.1
2
2.0200.aaaa.aaaa
Nashville
140.1.2.0/24
140.1.2.3
2
2.0200.cccc.cccc
Atlanta
140.1.3.0/24
140.1.3.1
3
3.0200.aaaa.aaaa
Boston
140.1.3.0/24
140.1.3.4
3
3.0200.dddd.dddd
Atlanta
Boston
Charlotte
140.1.11.0/24
Frame Relay
Partial Mesh
140.1.14.0/24
140.1.12.0/24
Nashville
140.1.13.0/24
s0
s0
s0
DLCI 52
DLCI 51
DLCI 54
DLCI 53
140.1.1.0/24
140.1.2.0/24
140.1.3.0/24
1
11
12
13
14
2
3
ch08.fm Page 540 Monday, March 20, 2000 5:17 PM