In ICT networking world, you always heard Switching and Routing. But What is Routing Protocols and its types and Why we use routing? Where its required?, how many type of Routing protocols are there. We will discuss all these questions and try to understand. about Static, Default and Dynamic Routing protocols
What is Routing
Routing is a process of identify the best path or find a best and shortest route for data to travel from the source to the destination across a network. It follows the next-hop router or gateway to forward the traffic. Next hope router or Gateways helps to data reaches its intended destination efficiently and reliably. A router or any layer-3 devices will be required to configure as Next hope Router or Gateway.
What is Protocol
Protocols are a set of rules and agreements that direct the communication between devices in a network. They define the format of data packets and order of data transmission, error handling, and other aspects of data exchange. Protocols ensure that devices can understand and interpret the data they receive, allowing for seamless communication.
Routing Metrics and Costs
These are some numeric values, based on these value Routing protocols take decision to select best path or route to forward the packet to desire destination.
Routing costs are numerical values derived from the routing metrics and are used to compare different paths to a destination
Below are the Metrics used in routing:
- Bandwidth
- Delay
- Reliability
- Load
- Hope Count
- Bandwidth: it is the capacity of a link to carry the traffic or data. Measured in bits per second (bps). Higher is preferred.
- Delay: time taken for a data packet to travel from the source to the destination. It is measured in milliseconds (ms). Lower is desirable.
- Reliability: it indicates the link reliability. It is usually represented as a decimal value between 0 and 1, with 1 being the most reliable. Higher are preferred.
- Load: it represents the current utilization of a link, indicating how much traffic is currently passing through it. Lower are preferred.
- Hope Count: it is the number of routers or hops that a packet must traverse to reach the destination. In some protocols, a lower is considered better.
Type of Routing protocol
Routing can be divided into 3 types
- Static routing
- Default routing
- Dynamic routing
Dynamic Routing can be divided in two types:
- Distance Vector
- Link state
Static Routing
It is type of routing method or type where administrator configure all routes manually for each and every subnet & Link. static routing requires manual intervention to define the paths that data packets should take from the source to the destination.
Some Key Feature of Static Routing
- Manual Configuration: It’s requiring manually configuration and can not take any decision to select best path dynamically or based on some matrices
- Fixed or Limited routes: As Static routing is recommended for small setup where we have less devices or connectivity and, in such setup, routes are very limited or fixed.
- Visibility of Traffic flow: As Route are less and manually configured, so administrator have more control and visibility that how traffic is flowing and travelling.
4. Required More Efforts: As administrator needs to configure each and every routes manually, so its require more efforts and time to configure every route and re-route if any device added, removed or changes.
In above example, we have configured specific Static route on both Switch and router (revers Route), so, when laptop user tries to access other network then switch should know how to route this request to reach Lo0 (8.8.8.8, 7.7.7.7, 9.9.9.9).
Format to configure static route is:
Ip route <Destination Address> < Destination Subnet mask> <next Hope address>
ip classless
ip route 8.8.8.8 255.255.255.255 10.1.1.1
ip route 7.7.7.7 255.255.255.255 10.1.1.1
ip route 9.9.9.9 255.255.255.255 10.1.1.1
Read this also: https://techblog.kbrosistechnologies.com/what-is-multilayer-switching-cef/
Default Routing
Default routing is a specific type of static routing used in computer networks to handle packets with destinations that are not explicitly defined in the routing table. If a layer-3 device received a packet with destination address without gateway address or with our any specific routing then it will use default route. But default route is not secure as we do not have any control on specific traffic and all traffic is allowed.
Generally, its use to create a single default route to reach all network.
In above example:
In Static routing, we have configured specific route for all 3 Lo address (7.7.7.7, 8.8.8.8 & 9.9.9.9). but in Default routing we no need to configure each and every route and only one default route can be configured, so, now we asked Switch that “you no need to bother about specific routes, please sent all traffic to your next hope gateways”.
Format to configure default route is:
Ip route <Any Destination Address> < Any Destination Subnet mask> <next Hope address>
Ip route 0.0.0.0 0.0.0.0 10.1.1.1
Dynamic Routing protocol
It is routing method select the best path to reach destination dynamically and based on their metrics. With Dynamic Routing we no need to configure any specific routes or much routing config. We only need to enable that dynamic routing protocol and rest routing protocol will select the best and shortest path, Create their own routing table.
Some key features of Dynamic Routing:
- Its requires if there are big data center and there are huge subnet or routing required like ISP.
- Automatic routing update, if there are any change in route.
- Automatic Routing table creation with best and shortest path
- Fast convergence
- Scalability
- Multiple paths to reach destination
- Less configurational efforts
- Much routing details and information
- Can manipulate as per requirement
Common dynamic routing protocols include:
- Routing Information Protocol (RIP)
- Open Shortest Path First (OSPF)
- Enhanced Interior Gateway Routing Protocol (EIGRP)
- Intermediate System to Intermediate System (IS-IS)
- Border Gateway Protocol (BGP)
Dynamic Routing has 2 flavours;
- Distance Vector (RIP, IGRP, EIGRP)
- Link State (OSPF, IS-IS)
BGP is neither Distance Vector nor Link State, it is an EGP (Exterior Gateway protocol)
Distance Vector Protocols:
Distance vector routing protocols, such as RIP (Routing Information Protocol) and IGRP (Interior Gateway Routing Protocol)—
- Calculate the distance (metric) to reach destination networks based on hop count
- Periodically exchange their entire routing table with neighbouring routers.
- It does not have full knowledge of the entire network topology
- Make decisions based on the information shared by adjacent routers.
Link-State Protocols:
Link-state routing protocols, such as OSPF (Open Shortest Path First) and IS-IS (Intermediate System to Intermediate System)—
- Exchange information about the state of their directly connected links with all other routers in the network.
- Each router creates a detailed map of the network’s topology and calculates the shortest path to reach each destination.
- Link-state protocols have a more comprehensive view of the network topology and converge faster than distance vector protocols.
Watch more Video https://www.youtube.com/channel/UCpcd6IshE1caAbf9EdJd3gw
https://www.youtube.com/channel/UCTbOmLTSlHggEBkt5wFGNRA
FAQ
Q. What is routing?
A. Routing is a process to route traffic or data to destination address.
Q. What is Protocol?
A. Protocol is some set up Rules.
Q. What is Routing Protocols?
A. Routing Protocols are some methods which use to travel the traffic based on metric and cost to determine the best and shortest path manually or dynamically.
