User`s guide

IP Address Allocation
5-3
8000-A2-GB21-10
June 1997
The following illustration is an example of host addressing.
97-15501-0
1
DSL Card
DSL Port 1
DSL Port 2
DSL Port 3
DSL Port 4
LAN Port
200.200.200. n /
255.255.255.0
200.200.200.1 /
255.255.255.255
200.200.200.2 /
255.255.255.255
200.200.200.3 /
255.255.255.255
200.200.200.4 /
255.255.255.255
RTU1
RTU2
RTU3
RTU4
ES1
ES2
ES3
ES4
n = Any valid IP address
Structured Subnet Addressing
As an alternative to using host routes for end-user systems, structured subnetting
can be used. It scales better and performs better, but it does not allow
geographically-dispersed subnets.
Structured subnet addressing uses the following method:
 Within the customer domain, the ISP would provision a subnet of its domain
to a DSL card and all devices behind it.
 The ISP would further subdivide that subnet into four additional subnets (one
behind each DSL port).
The following illustration is an example of structured subnet addressing.
97-15466-0
1
DSL Card
DSL Port 1
DSL Port 2
DSL Port 3
DSL Port 4
LAN Port
200.200.200. n /
255.255.255.0
200.200.200.240 /
255.255.255.240
200.200.200.224 /
255.255.255.240
200.200.200.208 /
255.255.255.240
200.200.200.192 /
255.255.255.240
RTU1
RTU2
RTU3
RTU4
n = Any valid IP address, but not within the other subnets