Saturday, September 18, 2010

ccna interview questions and answers.

What is routing?
Routing is a Process by which router consider the best path to the destined device, the election of the best path depends on various parameter and metrics, like bandwidth , time delay, HOP count , congestion and many more the whole result after the election of a best path that is also known as route is captured or stored under the router’s memory in a form of table is called Routing table Routing is the act of moving information across an internetwork from a source to a destination.

Types of routing.

There are three types of routing such as....
1 static routing.
2 Dynamic routing.
3 Default routing.

1. Static routing:- Static routing is process in which all path are manually configure by the network administrator. It’s manly used for small network because all route are configured by the network admin.

Advantage and disadvantage of static routing.

Advantage of static routing.
a) we can use cheaper router due to less processor because all the routes are configured manually by the network administrator , so router need not bother about finding or establishing route.

b) The cost for ISP link is saved, because in case of static routing router doesn’t take unnecessary wan link bandwidth for route convergence( convergence means , upgrading, finding or establishing a route in the routing table of a router.

c) it adds security because the administrator can choose to allow routing access to certain networks only.

Disadvantage of static routing.
a) The administrator have some sound knowledge about the network topology to configure a router for static routing, because administrator is only liable to give the route information to the router to deliver data packets form or to a network.

b) At the time of network expansion, the new network’s information or route should provided to the entire router’s routing table by hand by administrator.

c) Its not a handy for the large network , because maintaining would be a full-time job in itself.

2. Dynamic routing:-
Dynamic routing protocols are software applications that dynamically discover network destinations and how to get to them. A router will learn routes to all directly connected networks first. It will then learn routes from other routers that run the same routing protocol . The router will then sort through its list of routes and select one or more ‘best’ routes for each network destination it knows or has learned.

3. Default routing:-
Default routing is same as static routing but in the case of default routing administrator does not have knowledge of destination device. Default routing is used for small network.

What is Routing Protocol?
Routing protocol: A routing protocol is software application it used by router to dynamically find all the networks in the internet-work and to ensure that the all routers have the same routing table. Basically a routing protocol determines the path of a packet through an internet-work. Examples of routing protocol are IGRP, BGP, RIP, OSPF, etc.

What is Routed Protocol?
Routed protocol: When all routers know about the internet-work paths a routed protocol can be used to send user data packets through the established path routed protocols are assigned to an interface and determine the method of packet delivery. Examples of routed protocol are IPv4, IP V6, IPX etc.

What is administrative distance?
The administrative distance is used to judge the level of reliability of converged routing information for election the best route to a neighboring or remote router. An administrative distance is represented by numeric from 0 to 255, where the 0 is the most trusted and 255 means no traffic can pass through it.

Route Source Default AD
Connected Interface------------>0
Static Route-------------------->1
IGRP--------------------------> 100
External EIGRP---------------> 170
Unknown----------------------> 225

Type of routing protocol.
The routing protocol can be divided in to three subsequent groups; they are described as follows…….

1 Distance Vector:- The distance is the main parameter for the distance vector routing protocols, means the best path for the remote network is only be judging by the distance. sthe metric for the best route election or selection. And the vector indicates the direction to the remote site network. The distance vector routing protocol sends the entire routing table to its neighbor router. RIP and IGRP are the distance vector routing protocol.

2 Link state:- In link state protocols, also called shortest-path-first- protocol each router creates three separate tables. One of these table get track of directly attached neighbor information, one determines the physical orientation (topology) of the entire internetwork, and the last one is used as the routing table. Link-state protocols send updates containing thestate of their own links to all other routers on the network. OSPF is an example of link-state routing protocols.

3 Hybrid:- Hybrid protocols used both aspects of link –state as well as distance vector algorithm. EIGRP is an example of Hybrid routing protocol.


Anonymous said...


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Roshini RS said...

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Melisa said...

The information you have given here is truly helpful to me. CCNA- It’s a certification program based on routing & switching for starting level network engineers that helps improve your investment in knowledge of networking & increase the value of employer’s network.
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Andria BZ said...

The information you have given here is truly helpful to me. CCNA- It’s a certification program based on routing & switching for starting level network engineers that helps improve your investment in knowledge of networking & increase the value of employer’s network
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