Computer Networking

 Domain Name Service/System Has a table that maps IP addresses to the domain names All nodes on a network need to be aware of the DNS ip-address so that they can send the requests with domain-names to the DNS and then DNS can forward the request to respective destinations.

DHCP : Dynamic Host Configuration Protocol Network management protocal Assigns IP addresses, dynamically, to all the devices connected in a LAN  DHCP server also has an IP address because it is a device Here is an example of DHCP configuration To implement the DHCP service, we need the DHCP server

Components of a Computer Network Nodes End Nodes (Senders and Receivers) Intermediate Nodes e.g.  Hub Physical layer One-to-all (broadcasts), it is not one-to-to(unicast) Can't store or keep track of MAC addresses so can't unicast so may lead to unnecessary traffic in the network, not efficient! Receives data packets from one port and broadcasts it to all other ports e.g. a hub can have 8 or 4 or any number of ports and all these ports are connected to individual nodes(devices) Can be used to create LANs Repeater Physical layer Used to regenerate the signal over the same network before it becomes too weak They do not amplify but increase the intensity of the signal e.g. optic fibers can only be effective for sending signals without becoming weak for up to 60 km or so Also do not concern themselves with the MAC addresses for the machine Bridge Data-link layer Connects two LANs : One port - One LAN Uses MAC addresses to forward the data MAC addr. PC1 -> Port 1 MAC addr. PC1 -...

 

 Firewall is a security mechanism for networking traffic.

Gateways and Route Tables enable inter-network communications. There can be multiple gateways in a network which connect the network to different other networks, so a packet originating from inside this network needs to know which gateway to take up to reach its destination and Route Tables help the packet find the right gateway.

Dynamic Host Configuration Protocol Two questions: When we add a computer to a network, what is the IP address it is going to get? What is the DNS server in the network? We can either manually assign IP addresses to these computers and then manually configure the DNS for it OR  We can automate it and that is where DHCP comes into play, it automatically assigns an IP address to the computer that has been newly added to the network and manages the DNS related options for it.