User guide

Developing an IP Addressing Scheme Engineering Your IP Communications
164
pmp-0229 (Mar 2013)
Developing an IP Addressing Scheme
Network elements are accessed through IP Version 4 (IPv4) addressing.
A proper IP addressing method is critical to the operation and security of a network.
Each module requires an IP address on the network. This IP address is for only management
purposes. For security, you should either
• assign an unroutable IP address.
• assign a routable IP address only if a firewall is present to protect the module.
You will assign IP addresses to computers and network components by either static or dynamic IP
addressing. You will also assign the appropriate subnet mask and network gateway to each
module.
Address Resolution Protocol
As previously stated, the MAC address identifies a module in
• communications between modules.
• the data that modules store about each other.
• the data that BAM or Prizm applies to manage authentication and bandwidth.
The IP address is essential for data delivery through a router interface. Address Resolution
Protocol (ARP) correlates MAC addresses to IP addresses.
For communications to outside the network segment, ARP reads the network gateway address of
the router and translates it into the MAC address of the router. Then the communication is sent to
MAC address (physical network interface card) of the router.
For each router between the sending module and the destination, this sequence applies. The ARP
correlation is stored until the ARP cache times out.
Allocating Subnets
The subnet mask is a 32-bit binary number that filters the IP address. Where a subnet mask
contains a bit set to 1, the corresponding bit in the IP address is part of the network address.
Example IP Address and Subnet Mask
In Figure 53, the first 16 bits of the 32-bit IP address identify the network: