Sharing network addresses over remote locations
PR2000 Installation Guide
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9 Sharing network addresses over remote locations
In this Chapter
This chapter explains how to configure the PR2000 to emulate an IP bridge.
This is not a full bridge implementation and works only for IP networks. It allows
you to share the same network address over remote locations and, at the same
time, to avoid the waste of IP addresses that occurs with sub-netting.
If you do not need this feature, simply skip this chapter.
9.1 Sub-netting versus IP bridging emulation
IP network addresses are available in ranges from class A (16 million
addresses) to class B (64 thousand addresses) to class C (254 addresses). It is
becoming more and more difficult to get new IP address ranges.
IP sub-netting allows you to divide an IP network into smaller networks. One of
the reasons why someone would sub-net is to allow the use of one range of
addresses over two separate LAN networks.
The problem is that sub-netting can cause a waste of IP address. Every time a
network is sub-netted, there is a waste of at least two IP addresses per subnet
(because 0 and 255 are reserved addresses). Besides this, sub-netting forces
all the sub-nets to be the same size and the number of sub-nets to be a power
of 2 (2, 4, 8, etc). This might not be the best for your network.
IP Bridging Emulation is a feature offered by the PR2000 to emulate a bridge
and allow you to share the same network address over remote locations. By
avoiding sub-netting, you will conserve IP addresses and use them much more
efficiently. The PR2000 does this by allowing you to configure a continuous
range of IP address for each location and routing the packets from the LAN to
the WAN based on these IP addresses.
