Module 2 - Design the Network Structure

Section 4 - Design a Network-Layer Addressing and Naming Model

CareTaker Publications: Solution

• Use the contiguous Class C addresses defined in RFC 1918 Section 3 (192.168.0.0 to 192.168.255.255) within the bounds of CareTaker. A separate network will be defined for the WAN connection to the parent's router. This network address will be obtained from the parent company’s Network Operations. To keep things simple, the third octet will be used as a network number.
 
• For expansion, you might create address groups for the LAN and WAN. For example:

 
• 192.168.10.x through 192.168.19.x for the LANs
• 192.168.20.x through 192.168.29.x for the WANs
 
• With this grouping we would then make the following assignments:

 
• 192.168.10.x for the main facility
• 192.168.11.x for the warehouse facility
• 192.168.20.x for the main-to-warehouse WAN
 
• The last octet can be used to identify the network nodes on each network, which will provide 254 nodes for each of the facilities (main and warehouse). With this solution, the internal routers and PC/server nodes will support a simple 255.255.255.0 subnet mask. This is an attractive solution because it provides simplicity for an administrative staff that is not experienced with routers. Use of a 255.255.255.0 mask on the WANs could be seen as a waste, but there are so many addresses available that it is not important.
 
• The nodes should then be grouped by class for ease of identification. For example:

 
• 192.168.x.1 through 192.168.x.39 for the communications equipment
• 192.168.x.40 through 192.168.x.69 for the servers (file, print, mail, etc.) and hosts
• 192.168.x.60 through 192.168.x.254 for the user nodes

 
• The Windows NT DHCP should be installed on at least two of the Windows NT servers (depending on their location). Use these servers to dynamically assign IP addresses to the user computers.

• It would probably be best to name the servers with their department names suffixed with the last octet of the node address, which will aid in troubleshooting. The user nodes should have names that aid troubleshooting, such as the letters "PC" followed by a "hyphen" and the user's first initial and last name, such as PC-BSMITH.
 
• Because CareTaker is a Windows NT only shop, the Windows NT DNS should be installed as a local DNS, which will allow, at a minimum, addressing the ES9000 with something like es9000.caretaker.com. You should use Cisco’s DNS/DHCP Manager to synchronize DNS names with dynamically assigned IP addresses from DHCP.

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