How Do Network Routers Transfer Data
How does a router work:
How a router works is a small part of a larger process that allows network data packets to be sent from one network to another.
Routers all working together, direct network data packets like a traffic cop to the destination network.
This process assures that the network packets are delivered to the correct address or computer on that network.
There are many types of Wireless Network Tools which can be utilized to examine how networks communicating on the Internet, and not all speak the same language.
The following is an example of an Ethernet packet fully assembled and ready for transport.
Network cards installed in computers can speak different languages called “Protocols”.
The most common protocol used is IP, but there can be other protocol suites being used such as AppleTalk, DECNET and IPX/SPX.
How Does A Router Work
Let’s get started:
The router uses protocols to exchange information between networks while directing packets to their destination address. The source address and destination address must use the same protocols in order to communicate.
How does a router work to allow network packets to travel through other dissimilar networks along the way, such as Token Ring or DECNET, without having to be translated. It does this by using Address Resolution Protocol (ARP) to determine a network host’s physical address when only its IP is known.
How does a router work to use the most efficient route from source to destination is depending on the protocol being used. Some work by counting the number of “Hops” while others calculate the best service by analyzing the routes bandwidth.
How a router routes data over the Internet:
When a computer on one network wants to communicate with another computer on a different network, the information to be sent gets encapsulated into “Frames” or Ethernet packets to be sent over the network.
As the data transmits from the application on the users computer screen to the network card, its travels through a series of “Layers” transforming it from on screen data into “Packets” to be sent over the network.
These 7 layers are known as the (OSI) model or the Open Systems Interconnection.
Like a modem the data gets transformed from the “Application Layer” down to the “Physical Layer” where it leaves senders network card, travels across the Internet to the receivers network card where it starts at the “Physical Layer up to the “Application Layer” and ends up on the screen of the other user.
How does a router work to insure the packet gets delivered intact? It does this by containing the destination address, the senders address, and the data to be sent, and a few other pieces of error checking information to see it reaches the destination the same way it left the source.
|Preamble||Destination Address||Source Address||Packet Length||Message Data Frame||Error Check|
|64 bits||48 bits||48 bits||16 bits||368-12k bits||32 bits|
After the network packet it created it will contain the following information:
The preamble is created by the network card of the source computer containing a 64-bit field of synchronized binary ones and zeros, ending with two consecutive ones. After synchronization is complete the preamble is used to locate the first bit of the packet.
The destination address field is a 48-bit binary field that gets translated to the physical hardware address to where the packet is to be sent.
The source address field is a 48-bit field that contains the physical hardware or MAC address of the sender that is transmitting the packet.
The type field is 16-bit field which identifies higher level protocol associated with the packet used as the packet passes through the (OSI) layers.
The data field contains 46 to 1500 bytes of data to be transported. The data field is received from network layer, and then broken down into frames of information by layer 2 as it prepares for transporting.
The Cyclic Redundancy Check (CRC) field is a 32-bit error checking field, to make sure the packet reached its destination free of errors.
How Routers Determine The Path:
How does a router work to determine whether the destination address resides on the local network or on another network across the Internet is by examining the destination address information in the header packet.
When network packets are traveling over the Internet to their destination address they pass through many routers along the way.
Routers on the Internet all store information about their closest neighboring routers, by using an internal database called a “Routing Table”, which is dynamically being updated as destination times, delays, and other routers come on and off the network.
How does a router work to make its own local routing decision, is based on the information contained in its own internal routing table.
The router path of a network packet may be different during its return route.
Network traffic is constantly changing as routers pass new updated information between themselves.
When a router determines that it is directly connected to the destination network, it analyzes the packet header translates the 48bit binary destination address to the receiving computers physical hardware or MAC address.
That is how a router works! A giant leap from the days of the Pony Express.