What is a Network Router?
A router is used to pass data between different networks.
You may recall that in an IP address, the netmask identifies the 'network' part of the address. So in an address like 192.168.1.10 with a netmask of 255.255.255.0, the netmask 1s define the network address to be 192.168.1.0. If two addresses have different network parts of their addresses, they are in different networks, and require a router to share data.
Consequently, a device with address say 192.168.2.20 is in a different network, as the network address (192.168.1.0) is different. For messages to move from one network to another, hosts send these message to the default gateway, which is the entrance to the next network. These concepts are illustrated in this diagram, which features a switch (square icon) connected to a router (round).
There are many benefits of segregating networks:
- Faults such as broadcast storms are constrained to the network in which they occur; routers do not propagate broadcast traffic.
- Similarly, multicast traffic is not re-transmitted unless specifically enabled with a multicast routing protocol like PIM-DM for example.
- Through the use of access control lists, (ACL), routers can be configured to control the data routed from one network to another. This is used to limit access to resources (such as a printer), and also provides a degree of security.
Many industrial networks are small enough to not require segregation via a router, and what defines 'small enough' is hard to define. Natural boundaries however for routers tend to be along production cell lines and your tolerance for cross contamination of problems; if cell 1 network failed, could you tolerate it taking cell 2 with it? A simple routed interface using the EAGLE20 would create the cell boundaries necessary to avoid network fault contagion.
If you think a router or firewall may be of benefit to your network, or you would just like a review of your network design or topology, send an enquiry and we will arrange a service engineer to discuss the available services.