What is IP routing, and how does it work?
The simplest explanation of IP routing is the process of forwarding IP packets to the intended packet destinations. An example of such activity is when you enter URLs into browsers and expect to see the relevant page as a response. To fetch this return, your data can hop onto multiple servers.
IP routing protocols and tables guarantee that packets reach their stops as efficiently as possible. Additionally, users do not need to make changes as dynamic routing deals with appropriate packet delivery. However, static routing can help when you need to modify paths used to deliver data.
What is IP routing?
IP routing refers to the journey data takes to move from one computer or server to another. It follows a set of communication protocols to deliver data to its destinations, bouncing from multiple routers. IP routing relies on the routing algorithm and assesses data attributes to select the most appropriate path.
We can divide IP routing into multiple stages:
- A router receives a data packet and inspects its destination IP address.
- The router determines the best path for data by looking at its IP routing table. The routing table works like a map, consisting of all possible routes to a particular network.
- The router sends the packet to its destination or other hop addresses.
- The next router performs the same routine until the packet reaches its final stop.
So, IP routing efficiently delivers packets by finding the most practical route from source to destination.
IP routing in simpler terms
IP routing is a series of tasks necessary to get IP packets from one router to the next. This router-to-router journey continues until it reaches the destination in the IP header field.
This process is similar to transportation systems used in our real world. For instance, you might need to change buses several times to get home. The IP packet moves similarly, choosing the best available route.
Internet division: autonomous systems
The internet gets split into autonomous systems, representing router groups managed by one administrator. A network in an office can be an autonomous system. Also, Internet Service Providers (ISPs) can represent the admins of autonomous systems for their clients. In such cases, common routing protocols are in action.
What are routing tables in IP routing?
Routing tables are databases containing router locations based on IP addresses. Essentially, they work like maps for figuring out the paths of data packets. Each entry represents a remote router or network gateway that the router should recognize.
For instance, the router at your home usually has a rather humble routing table. It is because the router transfers outbound traffic to the ISP gateway.
So, IP routing tables provide information about efficient data routes. Each entry contains the destination address, subnet mask, and a field named route.
Comparing static and dynamic routing protocols
Administrators can adjust IP routing by setting static routing protocols, as in how specific data packets should travel. People usually achieve this by adding entries to routing tables. Thus, it is possible to configure the routing pathway manually.
An example from the real world can include how you choose to take home after work. It stays the same every day, as you pass the same streets and buildings without any variations. However, it also means that you can hit construction areas or traffic jams, slowing down your journey.
Dynamic IP routing comes in when you evaluate which path is the best for a particular occasion. This technique fetches new information about network changes and discovers new paths to specific destinations.
So, dynamic routing automatically adjusts and finds alternative routes if the previous ones are unavailable. It is similar to navigation software for finding traffic updates and new directions.
A more in-depth look into the IP routing
IP routing begins when routers receive a packet. Then, they inspect its header, containing details like its size, source, and destination. Now, routers know where the packet needs to end up but have no idea how to take it there. Thus, they look at routing tables to see how they should send the packet.
The next routers that receive the packet perform the same routine. And in reality, routers receive thousands or millions of packets. So, regular IP routing takes no more than seconds, jumping from one router to another along the way.
As mentioned, static IP routing does not change, and network admins set them manually. However, dynamic routing can be more efficient as they find the fastest paths for data.
What routing protocols are available?
A protocol represents a set of rules for sending and receiving data. Multiple variations assist packets in reaching their destinations:
- IP or Internet Protocol. It indicates the source and destination of data packets.
- BGP or Border Gateway Protocol. It showcases which networks are in charge of which IP addresses and relations between networks.
- RIP or Routing Information Protocol. It evaluates the number of routers that data packets will need to pass before reaching the destination. The number is hop count, helping find the fastest route.
- IS-IS or Intermediate System to Intermediate System. It assists with data packet transfers within a computer network.
- OSPF or Open Shortest Path First. It helps dynamic routing determine the most efficient route packets should take.
How can you add a static IP routing entry?
Regular users might not encounter situations when they need a static route. However, it can be helpful when you want your data packets to take a specific path.
Additionally, static routes have minimal overhead as it does not require network bandwidth. Furthermore, since you set static paths manually, you dodge the possibility of receiving faulty or unsecured routes.
If you feel confident about adding static routes, you can do it by following these steps:
- Open the Command Prompt window.
- Use the following command: route add  MASK 255.255.255.0 .
- 1 should reflect the point receiving the traffic. 2 is the destination that the traffic from 1 should reach. 255.255.255.0 stands for the subnet mask and it will suit most networks (unless there are some different network configurations).
- The static route will disappear after you reboot your device. To make it permanent, add -p like this: route -p add  MASK 255.255.255.0 .
Please note that static routing is an option for small networks. Larger ones will work more efficiently with dynamic routing.