Table of Contents
Module 2 - Design the Network Structure
Section 4 - Design a Network-Layer Addressing and Naming Model
PH Network Services Corporation: Solution
1. The hospital system has an existing IP network
with its own IP addresses. The hospital will be able to
assign two Class C addresses
to the PH Network: one for the WAN (202.12.27.0) and one for PH’s internal
use (202.12.28.0). Describe
your IP addressing plans for the implementation of PH’s network. You will
use
a Class C mask of 255.255.255.0
for the PH LAN. What mask will you use for the WAN?
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A ratio of 10 percent could normally be used for remote users to access
dial up connections. Because the network must have high availability to
the doctor offices, it would be better to raise this number to approximately
20 percent (24 simultaneous ISDN connections). A single PRI will provide
23 ISDN channels. Within the design, a second PRI could be added if PH
finds that the network is not available too often. A second PRI would bring
the total to 46 simultaneous connections if needed. If we assume, as a
worst case, that PH would need to supply network addresses for a router
at every doctor office, 57 WAN addresses would be needed. Six bits are
needed to represent the potential 57 networks, which would create a mask
of 255.255.255.252.
-
The network is relatively simple, but it would still be advisable to organize
address assignments for troubleshooting. Assign addresses 1 to 10 as communication
equipment and servers, the PH office PCs as 11 to 99, and the doctor offices
without LANs as 100 to 254. The office PCs and doctor office PCs should
be grouped in two pools for use by DHCP on the Windows NT server.
-
The subnet mask would be a simple 255.255.255.0 mask.
2. Update your topology diagram to reflect the
new addressing scheme.
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