Ccent, Ccna, Ccnp, Ccie Interview Questions

Ccent, Ccna, Ccnp, Ccie Interview Questions
Q-1 which layer of the OSI model is responsible for reliable connections?

Answer: The Transport layer of the OSI model is responsible for reliable connections.


Q-2 what is the difference between acknowledgments and handshaking?

Answer: Handshaking is used to negotiate the properties of a connection that is being established. Acknowledgments are used to tell the sender that data has been successfully received by the destination during the use of a connection.


Q-3 How many VTP modes are there and what are they?

Answer: Three: Server, Client, and Transparent


Q-4 what are the two types of Trunk encapsulation protocols?

Answer: IEEE 802.1Q and Cisco’s ISL


Q-5 what are the four primary no routable protocols?

Answer: SNA, NetBIOS, DEC LAT, DEC MOP


Q- 6 What is the difference between TCP and UDP?

Answer: The primary difference between TCP and UDP is that TCP is a connection oriented
protocol and UDP is a connectionless protocol.


Q- 7 What is HSRP?

Answer: HSRP, or the Hot Standby Routing Protocol, is a Cisco proprietary protocol
that brings routing functionality to end devices that would otherwise not be
capable of taking advantage of redundant network connections. HSRP enables
a pair of Cisco routers to work together to present the appearance of a single
virtual default-gateway to end devices on a LAN segment.


Q- 8 What is the difference between a Public IP address and a Private IP address?

A: Public address space is a unique address that is assigned to a company.
Private address space is not recognized by the Internet and can be used by anyone
within their private network


Q- 9 What does AAA stand for?

Answer: Authentication, authorization, and accounting


Q- 10 The H.323 protocol is used for what?

Answer: H.323 is used for multiservice (multimedia) applications, usually in a Voice
Over IP environment.

Free Cisco Ccna, Ccent, Ccnp Certification Tutorial

Free Cisco Ccna, Ccent, Ccnp Certification Tutorial
Routing

Routing is a relay system by which packets are forwarded from one device to another. Each device in the network as well as the network itself has a logical address so it can be identified and reached individually or as part of a larger group of devices. For a router to act as an effective relay device, it must be able to understand the logical topology of the network and to communicate with its neighboring devices.

The router understands several different logical addressing schemes and regularly exchanges topology information with other devices in the network. The mechanism of learning and maintaining awareness of the network topology is considered to be the routing function while the movement of traffic through the router is a separate function and is considered to be the switching function. Routing devices must perform both a routing and a switching function to be an effective relay device. A router receiving a packet from a host, the router will need to make a routing decision based on the protocol in use; the existence of the destination network address in its routing table; and the interface that is connected to the destination network. After the decision has been made the router will switch the packet to the appropriate interface on the router to forward

it out. If the destination logical network does not exist in the routing table, routing devices will discard the packet and to generate an Internet Control Message Protocol (ICMP) message to notify the sender of the event.

Routing Table

A routing table is a database repository that holds the router's routing information that represents each possible logical destination network that is known to the router. The entries for major networks are listed in ascending order and, most commonly, within each major network the sub networks are listed in descending

order. If the routing table entry points to an IP address, the router will perform a recursive lookup on that next-hop address until the router finds an interface to use. The router will switch the packet to the outbound interfaces buffer. The router will then determine the Layer 2 address that maps to the Layer 3 address. The packet will then be encapsulated in a Layer 2 frame appropriate for the type of encapsulation used by the outbound interface. The outbound interface will then place the packet on the medium and forward it to the next hop. The packet will continue this process until it reaches its destination. There are two ways in which a routing table can be populated: a route can be entered manually, this is called static routing, or routers can dynamically learning a route. Once a router learns a route, it is added to its route table.

Cisco CCNA, CCENT, And CCNP Home Lab Study: The DTE/DCE Cable

Cisco CCNA, CCENT, And CCNP Home Lab Study: The DTE/DCE Cable
Part of putting a home lab together is getting the right cables and understanding their usage. In this old Cisco home lab series, we'll take a look at the different cable types and how each fits into your home lab. The first cable type we'll look at is the multipurpose DTE/DCE cable.

More Cisco CCNA, CCENT, and CCNP candidates than ever before are putting together their own home labs for their certification exam study, and that's a great trend - there's nothing like learning on the real thing!

When I say "multi-purpose", I mean that while the cable will always perform the same task, it can be used in several different points in your home lab network. If you are going to have a frame relay switch - and you should get four if at all possible, since having your own frame relay cloud is a tremendous boost to your home lab studies and your exam score - you are going to require a DTE/DCE cable.

You can also use a DTE/DCE cable to directly connect one Cisco router serial interfaces and configure HDLC (the default) or PPP encapsulation over that point-to-point link.

Keyword: "almost". You must use the clockrate command on the DCE end of the connection in order to bring the line protocol up.

Most of today's DTE/DCE cables have "DTE" clearly stamped on four end of the cable - actually, "DTE" is probably embedded into the connector itself. Naturally, the other end will have "DCE" clearly indicated. it is the DCE end that will connect to your frame relay switch. If you are going to use a direct connection to run PPP or HDLC, it doesn't matter which end of the cable is connected to a given router.

If you are not sure which end of your DTE/DCE cable is connected to a given serial interface, use the show controller serial command to get that information. Most of the output of that command is not comprehensible, but what they require is right on top:

R3#show controller serial 1
HD unit 1, idb = 0x11B4DC, driver structure at 0x121868
buffer size 1524 HD unit 1, V.35 DCE cable

Whether you have your own frame relay switch or not, you'll require to pick up some DTE/DCE cables for direct connections between your Cisco home lab router's serial interfaces. don't forget to put the clockrate command on the DCE end of the cable! And if you are not familiar with a frame relay switch, check this same web-site soon for a tutorial that will show you how to set four up.

Naturally, if it is the DTE end, you'll see "DTE" there. And if you don't have anything connected to that interface, you'll see "no cable".

about any Cisco router can serve as a home lab frame relay switch, and two times you have got it configured, you are in nice shape - but it can be a little maddening to get it up and jogging in the first place. I'll show you how to avoid that aggravation in the next installment of this Cisco home lab tutorial series!