Here in this article, we have shared a basic introduction to Routing Protocols. and also, we have discussed types of routing protocols in the easiest way possible.
What is Routing Protocol in Computer Networks?
Routing Protocols are simply a set of defined rules used by the routers to communicate between source & destination. These protocols do not move the information from the source to a destination, but they update the routing table that contains the information.
Routes learned by routing protocol are known as dynamic routes. The goal of protocols is to exchange routing information between routers. protocols have a number of advantages in your network, including:
- You don’t have to manually configure every route on each router in the network, unlike with static routing.
- All you have to do now is configure the networks so that they are advertised on a router that is directly linked to them.
- Routers can announce that some routes have failed and chosen a different route to that network if a link fails and the network topology changes.
Types of Routing Protocols:
Routing Protocols can be divided in many ways. But in general, there are three categories that are as follows.
- Static Routing Protocol
- Dynamic Routing Protocol
- Default Routing Protocol
These categories are further divided into many routing protocols. We have shared all these one by one but first of all, let’s briefly discuss all Static and dynamic routing protocol.
Static Routing Protocol
When an administrator manually allocates the path from the source to the destination network, static routing protocols are employed. It improves the network’s security.
- There is no load on the router’s CPU.
- Between links, there is no unused bandwidth.
- Routes can only be added by the administrator.
- Each router’s connection must be known by the administrator.
- Because it is time-consuming, it is not a good choice for large networks.
- When a connection fails, the entire network goes down, which is impractical in small networks.
Dynamic Routing Protocol
Another important form of routing protocol is dynamic protocols. It enables routers to automatically add information from connected routers to their routing tables. When the topological structure of the network changes, these protocols send out topology updates.
- Even on larger networks, it’s easier to set up.
- It will be able to choose an alternate route dynamically if a link fails.
- It assists you in load balancing over many links.
Disadvantages / Negative aspects:
- Because updates are exchanged among routers, bandwidth is used.
- protocols increase the load on the router’s CPU or RAM.
Types of Dynamic Routing Protocols
Dynamic Routing protocols are further divided into two categories:
- Distance Vector Routing Protocol (RIP, IGRP)
- Link-State Routing Protocol (OSPF, IS-IS)
All of the aforementioned protocols are interior protocols (IGP), which implies they are used to share routing information within a single autonomous system.
BGP (Border Gateway Protocol) is an exterior protocol (EGP) for exchanging routing information between independent systems on the Internet.
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Distance Vectors Routing Protocols
Distance vector routing systems, as the name implies, employ distance to identify the optimum way to a faraway network. The distance is equivalent to the number of hops (routers) between the source and destination networks.
In most distance vector protocols, each neighbor receives the entire routing table (a neighbor is a directly connected router that runs the same protocol). To find the optimum routes, they use a variant of the Bellman-Ford algorithm.
Distance vector protocols are easier to build and manage than link-state protocols, but they are more prone to routing loops and converge slower than link-state routing methods. Because they communicate the entire routing database, distance vector methods consume more bandwidth than link-state protocols, which only send specific updates when topology changes.
Distance vector protocols include RIP and EIGRP.
Distance Vector Protocols use a lot of bandwidth and slowly converge to announce their routing table to every directly connected neighbor at specific time intervals.
When a route becomes unavailable in the Distance Vector protocol, all routing databases must be updated with new information.
- The network’s updates are shared on a regular basis, and it is always broadcast.
- The routing information received from neighboring routers is always trusted by this protocol.
- Contrary to popular belief, there are a number of disadvantages to using this method.
- Unnecessary traffic is generated as routing information is transmitted on a regular basis, consuming available bandwidth.
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Link-state Routing Protocols
The second type of routing protocol is a link-state protocol. They have the same basic goal as distance vector protocols, which is to discover the best path to a target, but they accomplish so in a different way. Link state protocols, unlike distance vector protocols, do not broadcast the whole routing table.
Instead, they broadcast network topology information (directly linked links, neighboring routers, etc.) such that all routers executing a link-state protocol have access to the same topology database.
Link state routing protocols converge significantly more quickly than distance vector routing protocols, and they offer classless routing, multicast updates, and triggered routing updates.
They also use more CPU and memory on the router than distance-vector routing protocols and are more difficult to configure.
Each router that uses the link-state protocol generates three tables:
- The neighbor table is a list of routers that are next to each other and use the same link-state protocol.
- The topology table is a table that stores the complete network’s topology.
- The routing table is a table that keeps track of the optimal routes.
Routing Protocols on the Internet:
Protocols that help data packets find their way across the Internet includes the following:
Routing Information Protocol (RIP)
In both LAN and WAN networks, RIP is used. It also runs on the OSI model’s Application layer. The Routing Information Protocol is the full name of this protocol. There are two variations of RIP.
- RIP Version 1
- RIP Version 2
The initial version, also known as RIPv1, aids in the determination of network pathways based on IP destination and hop count travel.
RIPv1 also communicates with the network by broadcasting its IP table to all network routers.
Because it delivers its routing table to a multicast address, RIPv2 is a little more advanced.
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Internal Gateways Protocols (IGP)
IGRP is a CISCO-developed subclass of the distance-vector internal gateway protocol. It was created to get around the RIP limits. Load, bandwidth, latency, MTU, and dependability are the metrics employed.
It’s a common way for routers to share routing information within an autonomous system.
Because it broadcasts every 90 seconds and has a maximum hop count of 255, this form of the protocol is appropriate for bigger networks.
In comparison to RIP, it allows you to maintain larger networks.
IGRP is also frequently used because it avoids routing loops by automatically updating itself when route changes occur within a network. It also has the option of balancing traffic across equal and unequal metric cost paths.
Goals of Routing protocols:
The following reasons need the use of protocols:
- Allows for the most optimal path selection.
- Allows for loop-free routing.
- Convergence occurs quickly.
- Update traffic should be kept to a minimum.
- Configuration is simple.
- Adapts to new situations
- Scales up to a colossal size
- Hosts and routers that are already in use are compatible.
- Variable length is supported.