A routing protocol is a method that routers use to share information with each other about networks they are connected to. We have seen in previous posts on this website (Creating a Static Route and Default Gateway of Last Resort) how we make routes ourselves and how to teach a router how to send packets […]
Before we can start to explain how routing protocols work, we need an understanding of wildcard masks. The concept of wildcard mask is one that many people struggle with at first, but with a little time and practice it’s becomes second nature. Converting a full class subnet mask into a wildcard mask quite straight […]
The Cisco administrative distance is a value assigned to all routing protocols to define how trustworthy the information is. If a Cisco router has multiple routes in its routing table for the same network, it looks to see which route has the lowest cost/metric value. The problem with using cost values is that different […]
In yesterday’s post ‘Static Routing’ we saw that we needed to create a static route to allow the Cisco router “AOIP.ORG” to ping “R2”. The static route that we created was ‘ip route 10.0.1.0 255.255.255.0 192.168.1.1’ and ping was successful to the IP address 10.0.1.2 (R2’s Serial interface). The problem with that configuration was that […]
A router by default only knows about networks that are directly connected to it. If a router is not directly connected to the final destination subnet, then the router needs to learn, or be told how to get to that destination. Learning routes can take place through the use of routing protocols, however in […]
In order to set up an IP address on an interface, we need to be in the interface level of the command line. This is a level within the global configuration level. From global configuration mode, we can enter the ‘interface serial 1/0’ command. If you are unsure of what interfaces are on the router, […]
CIDR was invented in 1990, and was the change that allowed routers to use classless addresses to route traffic instead of class-full addresses. This helped a huge amount as before its invention, routers could only route traffic based on full classes. If we look at Class A address for example, there are only 126 of […]
As the name indicates, and IP address is an address that computer equipment uses to be able to communicate with each other. It is made up of 4 octets (separated by a ‘.’), each of which is 8 bits in size (32 bits in total). If we look at our binary table for 8 bits, […]