CCNA INTERVIEW Q&A
Q. What is a router?
A.
A router is a device that connects more than one physical network, or
segments of a network, using IP routing software. As packets reach the
router, the router reads them and forwards them to their destination.
Q. Discuss wireless networking.
A.
This is a network configured to use communication techniques such as
infrared, cellular, or microwave, so that cable connections are not
required.
Q. Discuss WAN (wide area network).
A.
A WAN is extended over longer distances that a LAN (local area
network). It can range from a few miles to across the world. TCP/IP is
the primary WAN protocol and was developed to provide reliable, secure
data transmissions over long distances.
Q. What is OSPF?
A. Open Shortest Path First is a routing protocol that supports the concept of a core area to which everything attaches.
Q. What is BGP?
A.
Border Gateway Protocol is used for routing between networks on the
Internet core, and it supports many advanced routing features.
Q. What is an autonomous system?
A.
An autonomous system is a community of interest. Used in conjunction
with routing protocols, it breaks up parts of the network into
manageable chunks.
Q. What is dial on demand?
A.
Dial on demand is a technology that only activates network connection
when “interesting” packets are to be sent across the infrastructure.
Q. What mask would you use to supernet two class C addresses?
A. The subnet would be 255.255.254.0.
Q. What is VLANing?
A.
Virtual LAN is used on large LANs to break up the network into smaller
broadcast domains. This creates communities of interest. These
communities can be based around organizational structures.
Q. What is CIDR?
A.
Classless Internet domain routing is used in conjunction with classless
routing protocols to summarize the Internet into smaller routing
tables.
Q. What is VLSM?
A. Variable Length Subnet Mask is used to allocate the amount of address space required by the end network.
Q. What is a class D IP address?
A. Class D addresses are multicast addresses.
Q. What addresses do multicasts start with?
A. Multicasts start with the address 224.0.0.0.
Q. Which name resolution system is implemented with TCP/IP by default?
A.
Although WINS is a name resolution that is implemented by TCP/IP by
default, it only works on Windows-based networks. The only true name
resolution system that almost every TCP/IP networks uses is DNS.
Q.
You are the administrator of a 100-station Ethernet network. Your users
are complaining of slow network speeds. What could you replace your hub
with to increase your network throughput?
A.
A switch would increase performance by making virtual, direct
connections between sender and receiver. A bridge and router would
actually decrease performance because these devices introduce latency
into the communication.
Q. Which TCP/IP utility is most often used to test whether an IP host is up and functional?
A. The Ping utility is the most often used TCP/IP utility because it allows you to test individual hosts.
Q. Which utility can you use to find the MAC and TCP/IP address of your Windows NT or 2000 workstation?
A.
The ipconfig utility is available for both these operating systems. It
displays information like the MAC and TCP/IP address of your workstation
as well as other TCP/IP configuration information.
Q. Which utility can you use to verify a packet’s path?
A. The tracert utility traces the route from the source IP host to the destination host.
Q. Which WAN technology uses digital signaling from sender to receiver?
A.
The T-series of WAN connection (such as T1, T3, and so on) uses digital
signaling from sending hardware to receiving hardware.
Q.
You are setting up a workstation for remote access to the office. The
office has a modem pool configured, and it is working correctly. The
required results are that the workstation and modem bank must establish a
connection and that the server at the office must authenticate the
workstation. Optionally, the workstation and office must be able to
communicate by using a single protocol, and the workstation must be able
to access all network devices at the office. The proposed solution is
to install a POTS telephone line, modem cable, and modem connected to
the workstation. How would you configure the protocols to achieve the
desired results?
A.
This question tests your ability to configure protocols and select the
best one to meet the connectivity requirements. The recommended protocol
here would be TCP/IP since it can be used across the different access
methods.
Q. Which remote access protocol can run over both serial and parallel connections?
A. Because PPP doesn’t contain a physical layer specification as part of the protocol, it can run over any kind of medium.
Q. What Microsoft TCP/IP protocol can be used over the Internet to create a secure, virtual network?
A.
The Point-to-Point Tunneling Protocol (PPTP) allows you to create a
secure, virtual connection between two points by tunneling one protocol
inside another. Usually, a PPP connection is opened over a TCP/IP link.
Q. Which type of firewall checks for a current communication and the next packet needed?
A. A proxy provides firewall services by keeping track of all communications sessions and “prefetching” the next packets.
Q. Which type of security uses a file that identifies predefined IP addresses that are allowed to send data through a router?
A.
Access Control List security uses a file (the ACL) that identifies
which addresses can send data through a particular firewall or router.
A broadcast domain is a logical division of a computer network, in which all nodes can reach each other by broadcast at the data link layer. A broadcast domain can be within the same LAN or it can be routed towards other LAN segments.
A collision domain is a physical network segment where data packets can "collide" with one another for being sent on a shared medium, in particular in the Ethernet
networking protocol. A network collision is a scenario wherein one
particular device sends a packet on a network segment, forcing every
other device on that same segment to pay attention to it. Meanwhile,
another device does the same, and the two competing packets are
discarded and re-sent one at a time. This becomes a source of
inefficiency in the network
