Interview Fundas

What does CIDR stands for?
A. CIDR (Classless Inter-Domain Routing) is a way to allocate and specify the Internet addresses used in inter-domain routing
B. Classless internet domain routing (CIDR), if default routing this is very useful where we don't need to very much about what is the subnetting about that class of IP's.

What is a Bridge? When is it used? How is a bridge configured? What are the software and hardware components?
A bridge is a layer 2 device - it works based on MAC address. Bridge is s/w
based. It is usually used to bridge 2 networks (or even more in recent times)
Bridge is configured by having the MAC address of the switches connected
directly to it.

Can we use static and dynamic routing in one network?
We can use static and Dynamic Routing in one network. However Dynamic Routing is used to have the best path no matter what the status of the physical links. All routing protocols have some sort of shortest-path or lowest-cost or best-choice algorithm to help you weigh all the options available. Static routing can be used in a small network to reduce the work of the network administrator or to use a particular route only to forward the packet; we need Static routing.

What are the advantages and disadvantages of the three types of routing tables?
The three types of routing tables are fixed, dynamic, and fixed central. The fixed table must be manually modified every time there is a change.
A dynamic table changes its information based on network traffic, reducing the amount of manual maintenance.
A fixed central table lets a manager modify only one table, which is then read by other devices. The fixed central table reduces the need to update each machine's table, as with the fixed table.
Usually a dynamic table causes the fewest problems for a network administrator, although the table's contents can change without the administrator being aware of the change.

What is BGP (Border Gateway Protocol)?
It is a protocol used to advertise the set of networks that can be reached with in an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol).

What is autonomous system?
It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol.

What is ICMP?
ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test / reply to test whether a destination is reachable and responding. It also handles both control and error messages.

What is difference between ARP and RARP?
The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48 bit physical address, used by a host or a router to find the physical address of another host on its network by sending a ARP query packet that includes the IP address of the receiver.
The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address.