A sample text widget

Etiam pulvinar consectetur dolor sed malesuada. Ut convallis euismod dolor nec pretium. Nunc ut tristique massa.

Nam sodales mi vitae dolor ullamcorper et vulputate enim accumsan. Morbi orci magna, tincidunt vitae molestie nec, molestie at mi. Nulla nulla lorem, suscipit in posuere in, interdum non magna.

What is meant by IP Routing Process?

The Process of IP Routing

– There is a characteristic feature of this process that it does not changes with the size of the network.
– The way it is implemented is same throughout all types and sizes of the network.
For example :
– There are 2 networks namely A and B.
– There is a router R that connects these two networks.
– Also, this router has 2 interfaces namely E0 and E1 similar to the network interface of a network card.
– The only difference is that they are built in to the router.
– A host A in network A wants to communicate with a host B in network B.
– It opens the command prompt and enter the following:
– By this it requests for a remote host, implying that the data packet must be routed to the host and so it should be sent to the router.
– The ARP or the address resolution protocol can be used along with IP for determining which network packet is meant for which host.
– Now for sending the packet to the router, the host A must have knowledge about the hardware address of the interface of the router R.
– This hardware address is nothing but the MAC address of E0 interface.
– For this address, the host looks up in the ARP cache.
– The MAC address is available in this memory for just a few seconds.
– If the MAC address is not there it implies one of the following things:
1. Either there has been a long time since last connection between the host and the router.
2. Or it might not have resolved the router’s IP address in to the MAC address.

– In such a situation, the host broadcasts and ARP request which seeks to obtain the MAC address of that router stating by stating the IP address.
– The router identifies this IP address as being its own and responds back to the host with its hardware address.
– This also explains why there occurs a timeout during the first ping.
– Sending an ARP and getting a response back is a time consuming process.
– By the time, your system gets a response back; the Time to Live (TTL) of the ping expires.
– Now, the host has the address, it has everything that it requires for transmitting the packet.
– When the packet is transmitted to the router, it is handed over to the network layer which in turn passes it to the data link layer.
– The source as well as the destination IP addresses along with the ICMP echo request are contained within this data packet.
– A frame is created by the data link layer of the network A for encapsulating the packet information such as the addresses and the type field.
– At the end in the FCS part, A CRC process is carried out by the data link layer in order to ensure that any corruption in the data packet can be recognized by the receiving host.
– This frame is handed over to the physical layer that encodes it into a digital signal and transmits it across the network in to network B.
– This signal is received by the router which again carries out a CRC check.
– After this the destination address contained in the frame is checked against the addresses of various hosts.
– When a match is found, the original packet (stripped off its frame) is stored in the buffer of the router.
– The IP protocol checks the destination address and creates a frame and sends it to the host B.
– Here the decapsulation process takes place.

Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>