Types of routing
It is a very very very important topic in networking whether you are looking for career in security then also you have to have knowledge of routing and its protocols.
Once you create an inter network by connecting your WAN and LAN to a router, you will need to configure logical network address, such as IP address to all hosts on the inter network so that they communicate across network.
The term routing is used for taking a packet from one device and sending to another across the network.
To be able to route a packets a route must know at a minimum the following:
Destination address
Neighbor routers from which it can learn about remote networks
Possible routes to all network
The best route to each network
How to maintain and verify routing information
Routing are of three types :
1) Static Routing
2) Dynamic Routing
3) Default Routing
Static Routing: In This Type of routing all the routes are assigned to the routers by administrator manually. Each route is known by System admin. if network is large then it is difficult to remember all the path and most important thing is if any network is down then it took lots of time of admin to find out which network is down and what is the issues.
Dynamic Routing: In dynamic routing best path to reach network is selected by router. There are different routing protocols to calculate best path to reach network. Best path is calculated on hop count , bandwidth ,delay etc.
Default Routing:
Default route which is also known as the gateway of last resort, is used in forwarding packets whose destination address does not match any route in the routing table. In IPv4 the CIDR notation for a default route is 0.0.0.0/0 and ::/0 in IPv6. Now since the both the host/network portion and the prefix length is zero a default route is the shortest possible match. In previous lessons in which we discussed basics of IP Routing we know that a router when performing a route lookup will select a route with longest possible match based on CID specifications, however if packet does not match any route in the routing table it will match a default route, the shortest possible route, if it exists in the routing table. A default route is very useful in network where learning all the more specific routes is not desirable such as in case of stub networks. A default is immensely useful when a router is connected to the Internet as without a default route the router must have the routing entry for all networks on the Internet which are in numbers of several hundred thousand, however with single route configured as the default the router will only need to know the destinations internal to the administrative domain and forward IP packets for any other address towards the Internet using the default router. The default gateway is a device such as a router that serves as the edge devices providing an access point to other networks and is used to forward IP packets which does not match any routes in the routing table. We usually encounter the concept of default gateways in our daily computer life. The LAN configuration in our windows requires us to specify the IP address, Subnet Mask and the Default Gateway to access the Internet. The default gateway IP address is the IP address of the CPE or Internet modems which provide the connectivity to the Internet, now since the Internet has several hundred thousand routes which we cannot install in our table, we simply tell our computer to forward all packets destined to the Internet to this device. Again the CPE will itself have a default route and gateway configured which will point to the ISP access device.
Once you create an inter network by connecting your WAN and LAN to a router, you will need to configure logical network address, such as IP address to all hosts on the inter network so that they communicate across network.
The term routing is used for taking a packet from one device and sending to another across the network.
To be able to route a packets a route must know at a minimum the following:
Destination address
Neighbor routers from which it can learn about remote networks
Possible routes to all network
The best route to each network
How to maintain and verify routing information
Routing are of three types :
1) Static Routing
2) Dynamic Routing
3) Default Routing
Static Routing: In This Type of routing all the routes are assigned to the routers by administrator manually. Each route is known by System admin. if network is large then it is difficult to remember all the path and most important thing is if any network is down then it took lots of time of admin to find out which network is down and what is the issues.
Dynamic Routing: In dynamic routing best path to reach network is selected by router. There are different routing protocols to calculate best path to reach network. Best path is calculated on hop count , bandwidth ,delay etc.
Default Routing:
Default route which is also known as the gateway of last resort, is used in forwarding packets whose destination address does not match any route in the routing table. In IPv4 the CIDR notation for a default route is 0.0.0.0/0 and ::/0 in IPv6. Now since the both the host/network portion and the prefix length is zero a default route is the shortest possible match. In previous lessons in which we discussed basics of IP Routing we know that a router when performing a route lookup will select a route with longest possible match based on CID specifications, however if packet does not match any route in the routing table it will match a default route, the shortest possible route, if it exists in the routing table. A default route is very useful in network where learning all the more specific routes is not desirable such as in case of stub networks. A default is immensely useful when a router is connected to the Internet as without a default route the router must have the routing entry for all networks on the Internet which are in numbers of several hundred thousand, however with single route configured as the default the router will only need to know the destinations internal to the administrative domain and forward IP packets for any other address towards the Internet using the default router. The default gateway is a device such as a router that serves as the edge devices providing an access point to other networks and is used to forward IP packets which does not match any routes in the routing table. We usually encounter the concept of default gateways in our daily computer life. The LAN configuration in our windows requires us to specify the IP address, Subnet Mask and the Default Gateway to access the Internet. The default gateway IP address is the IP address of the CPE or Internet modems which provide the connectivity to the Internet, now since the Internet has several hundred thousand routes which we cannot install in our table, we simply tell our computer to forward all packets destined to the Internet to this device. Again the CPE will itself have a default route and gateway configured which will point to the ISP access device.
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