What is Routing?
In terms of Networking, Routing is a process to select a specific path from more than one network. In networks there may be any type of network, maybe it’s a local network or maybe any metropolitan network. There are main two types of networks where the process of routing is used. These are Public Switched Telephone Networks and Internet(WWW).
Purpose of Routing
The basic purpose of routing is to connect different networks together to allow them to communicate and pass data traffic between them. Most often routing protocols are how networks determine where to send network traffic. That’s the route that they will take. In these routing protocols build maps.
Actually, they build routing tables that we’ll get to that later, that they use for directing network traffic. routing is what makes this interconnected world function as well as it does. Networking would be pure chaos without it as we’d have no idea where to send traffic. Now let’s move on to some basic routing concepts. First up is static routing.
What is Static Routing?
Static routing uses administrator-defined routes. Each router in a static routing configuration must contain the route. A static route from router a to router B requires that router B has a static route back to router a, in order for two-way communication to take place.
If we had a static route from A to B, and B didn’t have one back to a, a could send traffic to B but b could not send traffic back to A.
Now static routing is easy to set up in small networks. But it’s not so easy to maintain. Networks change all the time. With static routing. When a change occurs in routers, the administrator has to go around to each router and implement that change. Then there’s dynamic routing. This is where routers use protocols in order to determine the best route between two networks.
The administrator determines which protocols will be used on the routers. In order for the routers to communicate, they must all be using the same protocols. There is an exception to that. And that’s route redistribution. An administrator can configure a router to take one dynamic protocol and transform it into a different routing protocol to be used from that point on.
This is the only case when routing protocols can be different across the network. routing protocols can be stacked within a router which means that there can be more than one dynamic routing protocol programmed into a router.
What is Dynamic Routing?
Dynamic routing is very fluid and dynamic in it’s what makes possible today’s interconnected world. The next concept is the default route. The default route is the direction that a router will send network traffic when there is no known route in the routing table. The default route is assigned by an administrator, it is usually a designated interface on the router or it is the next designated next-hop interface. Then there is the routing table.
In other words, Dynamic routing is a method of distributing traffic among multiple servers based on the load each server is experiencing. To do this, we need to have some kind of metric that tells us how busy each server is.
We use two metrics here:
a) Requests per second (RPS),
b) Average latency.
Request per second (RPS)
The first metric we use is the number of requests per second. A request is any HTTP request sent to our website. If we have 10 users requesting pages at once, we would say we have 100 requests per second.
The second metric we use is the average latency between the client and the server. Average latency is calculated by dividing the total time spent waiting for a response by the total number of requests. So if we have 10 users making a request, and the average response time is 5 seconds, the average latency will be 50%.
What is the Routing Table?
The routing table is a list of known routes to all known networks. From the router’s perspective, it is established by an administrator when static routing is used. It is dynamically built by routing protocols when dynamic routing is employed. Each routing protocol maintains its own routing table. Different routing protocols may have different routes to the same network.
The loopback interface is an administratively configured logical number assigned to a router to ease administrative functions or routing processes. Often the loopback interface is a sign in an ipv4 address format, even when ipv4 isn’t used on the router. Many routing protocols have been designed to take the loopback interface into account when performing administrative functions.
The loopback interface may be completely logical or a physical interface may be assigned to be the loopback interface. Let’s move on to routing loops.
What is the Routing loop?
A routing loop is possible. The problem can be created if interconnected routers have a breakdown in their routing algorithms. When a routing loop occurs. Network traffic keeps looping through the routers until some system or mechanism breaks the cycle.
Routing loops can create network congestion, or even bring down a network. routing protocols use multiple methods to prevent routing loops from occurring.
One of the main methods that they use is what’s called the time to live field for the TTL field. The TTL field keeps track of how long that packet has been in existence and how far it is traveled. And after a specified amount of time or distance, it will inform the next router to drop it. This helps to prevent routing loops.
That concludes this article on the introduction to the router concept, part one, In this article, I explain the purpose of routing. And then I moved on to some basic routing concepts.
You can also go throw our other articles that are mentioned below