CS610 - Computer Network Solved Subjective from Finalterm Papers
CS610 Current Final Term Papers
Fall 2012
Q: differentiate between IP and transport protocol with the help of example. (2 Marks)
Answer: - (Page 119)
1-IP provides computer-to-computer communication while TP provide application-to-application
communication.
2-IP source and destination addresses are computers while TP need extended addressing mechanisms to
identify applications
3-IP is also called machine-to-machine communication while TP are called end-to-end communication.
Q: Give the main advantage and disadvantage of RIP. (2 Marks)
Answer: - click here for detail
The biggest advantage of RIP is that it is simple to configure and deploy.
The biggest disadvantage of RIP is its inability to scale to large or very large networks. The maximum hop
count used by RIP routers is 15.Another disadvantage of RIP is its high recovery time.
Q: Tel the first assignable IP address from a 128.140.80.24/20. (2 Marks)
Answer: - Click here for detail
The host address range for this subnet is 128.140.80.1 - 128.140.95.254, so the first assignable IP address is
128.140.80.1.
Q: how was the NAT implemented? (2 Marks)
Answer: - (Page 130)
We can see that the old and new values of IP source field and destination field are shown with their directions.
NAT device stores state information in table. The value is entered in the table when NAT box receives outgoing
datagram from new.2
Q: IS ATM including LAN and WAN network. If yes what kind of connection is established? (2 Marks)
Answer: - (Page 66)
Yes it includes LAN and WAN network and established connection-oriented connection.
Q: is IP multicasting beneficial? Defend your answer with proper reason. (3 Marks)
Answer: - Click here for detail
We assume that IP multicast is more beneficial for the channels with a high popularity, and therefore these
channels will be preferred when the number of available multicast groups is smaller than the number of
channels.
Q: Can the length of the segment be increased 500 meter by adding three repeater one with each
segment. It can be done or not. (3 Marks)
Answer: (Page 49)
One repeater doubles, two repeaters triple the maximum cable length limitation. It is to be noted that we cannot
increase the maximum cable length as many times as we wish by just adding repeaters.
Q: How an administrator can handle static and dynamic routing. (3 Marks)
Answer: - Click here for detail
Routing can be handled by a static routing table built by the system administrator. Static tables do not
dynamically adjust to changing network conditions, so each change in the table is made manually by the
network administrator.
Routing can be handled by a dynamic routing table that responds to changing network condition. Dynamic
routing tables are built by routing protocols.
Q: IS TCP/IP suit including ARP. What kind of messages are in ARP. (3 Marks)
Answer: - (Page 97)
The TCP/IP protocol suite includes an Address Resolution Protocol (ARP).
The ARP standard defines two basic message types:
• Request
• Response
Q: Traceroute continues to increment the Time To Live until the value is large enough for the datagram
to reach its final destination. What happens when the TTL is sufficiently large for the datagram to reach
its destination? (3 Marks)
Answer: - Click here for detail
To learn when a datagram reaches its destination, traceroute sets the UDP destination port number in the
datagram to a very large value that the destination host is unlikely to be using. When a host receives a datagram
destined to it containing a destination port number that is unused locally, it sends an ICMP port-unreachable
error to the source.3
Q: describe characteristics of BGP. (5 Marks)
Answer: - (Page 138)
It is most popular Exterior Gateway Protocol in Internet. It has following
characteristics:
"It provides routing among autonomous systems (EGP).
"It provides policies to control routes advertised.
"It uses reliable transport (TCP).
"It gives path of autonomous systems for each destination.
"Currently the EGP is of choice in the Internet.
"The current version is four (BGP-4).
"It provides facilities for Transit Routing.
Q: describe IPV6 addressing notation. (5 Marks)
Answer: - (Page 114)
128-bit addresses unwisely in dotted decimal; requires 16 numbers:
105.220.136.100.255.255.255.255.0.0.18.128.140.10.255.255
Groups of 16-bit numbers in hex separated by colons – colon hexadecimal (or colon hex).
69DC: 8864:FFFF: FFFF: 0:1280:8C0A:FFFF
Zero-compression – series of zeroes indicated by two colons
FF0C: 0:0:0:0:0:0:B1
FF0C::B1
IPv6 address with 96 leading zeros is interpreted to hold an IPv4 address.
Q have there is a technique for achieving reliability through TCP. (5 Marks)
Answer: - (Page 123)
Reliability is the responsibility of the Transport layer. In TCP/IP, TCP provides reliable transport service. Most
Internet applications use TCP as no other protocol has proved to work better.
SERVICE PROVIDED BY TCP:
Following are the services provided by TCP:
• Connection-oriented service
• Point-to-point
• Complete reliability
• Full-duplex communication
• Stream interface
• Reliable connection startup
• Graceful connection shutdown4
CS610 Current Final Term Papers
Fall 2012
Is there any technique for achieving reliability through TCP? (5 Marks)
Answer: - rep
2. Give reasons for which IPv4 need to be changed? (5 Marks)
Answer:- (Page 110)
One of the parameters, which motivated IP for change, is address space. The 32-bit address space allows for
over a million networks.
But most networks are class C and too small for many organizations. 214 class B network addresses already
almost exhausted (and exhaustion was first predicted to occur, a couple of years ago).
The second parameter is type of service, the IP provides. Different applications have different requirements for
delivery reliability and speed. Current IP has type of service that is not often implemented. Another factor for
the motivation for change is multicast.
3. In a star organization there are 120 systems connected in a network. Give your comments about delay;
delay should be smaller or larger. Give reasons? (5 Marks)
4. How TCP provides reliability? (3 Marks)
Answer: - (Page 125)
TCP achieves reliability by retransmission. An acknowledgement is used to verify that data has arrived
successfully. If acknowledgement does not arrive, the previous data is retransmitted.
5. How TCP and IP interact with each other? (3 Marks)
Answer: - (Page 123)
TCP uses IP to carry messages. TCP message is encapsulated in IP datagram and sent to the destination. On the
destination host, IP passes the contents to TCP. It is shown in the figure below.
6. Describe four factors for network classification? (2 Marks)
Answer: - (Page 4)
Computer networks are classified by four factors which are as follow:
1) BY SIZE:
2) BY CONNECTIVITY:
3) BY MEDIUM:
4) BY MOBILITY:5
CS610 Current Final Term Papers
Fall 2012
Q1- What is ICMP and what type of errors internet layer can detect? (5 Marks)
Answer: - (Page115)
Internet control Message Protocol (ICMP) defines error and informational
messages. These are given as follows:
1. ERROR MESSAGES:
These are as follows:
• Source quench
• Time exceeded
• Destination unreachable
• Redirect
• Fragmentation required
Q2- In which situation RIP support for default routers? (5 Marks)
Q3- Give Pros and Cons of static and Dynamic routing. (5 Marks)
Answer: - Click here for detail
Pros and Cons of Static Routing
Static routing is not really a routing protocol. Static routing is simply the process of manually entering
routes into a device's routing table via a configuration file that is loaded when the routing device starts
up.
Static routing is the simplest form of routing, but it is a manual process.
Use static routing when you have very few devices to configure (<5) and when you know the routes will
probably never change.
Static routing also does not handle failures in external networks well because any route that is
configured manually must be updated or reconfigured manually to fix or repair any lost connectivity.
Pros and Cons of Dynamic Routing
Dynamic routing protocols are supported by software applications running on the routing device (the
router) which dynamically learn network destinations and how to get to them and also advertise those
destinations to other routers.
A router using dynamic routing will 'learn' the routes to all networks that are directly connected to the
device.
Next, the router will learn routes from other routers that run the same routing protocol (RIP, RIP2,
EIGRP, OSPF, IS-IS, BGP etc). Each router will then sort through it's list of routes and select one or
more 'best' routes for each network destination the router knows or has learned.
Dynamic routing protocols have the ability to adapt to logical network topology changes, equipment
failures or network outages 'on the fly'.6
Q4- How ICMP used to test different tools? (3 Marks)
Answer:- (Page 117)
ICMP can also be used to test different tools. An Internet host A, is reachable from another host B, if datagrams
can be delivered from A to B. Ping program tests reach ability. It sends datagram from B to A that echoes back
to B. it uses ICMP echo request and echo reply messages. Internet layer includes code to reply to incoming
ICMP echo request messages.
Q5 - How does host join and leave a group? (3 Marks)
Answer: - (Page 142)
A standard protocol exists that allows a host to inform a nearby router whenever the host needs to join or leave
a particular multicast group known as Internet Group Multicast Protocol (IGMP). The computer uses IGMP to
inform the local router about the last application when it leaves.
Q6- When packet lost what is the procedure TCP adopt? (3 Marks)
Answer: - Click here for detail
When a retransmitted TCP packet is lost (i.e., retransmission fails) most implementations do not have a
mechanism to recover the packet without waiting for a retransmission time out and subsequent Slow Start.
packet is lost for any reason, TCP adopts a sliding window approach, that is the sender keeps sending a few
other packets even if it has not received the ACK for
the missing packet, in case the lost packet will arrive out of order
Q7- In this subnet blocks 192.168.1.0/26 What is the range of assignable host address? (3 Marks)
Q8 - Write the difference between Explicit and implicit frame type. (3 Marks)
Answer: - (Page 35)
In EXPLICIT FRAME TYPE the identifying value is included with frame describes types of included data
while in implicit frame the receiver must infer from frame data.
Q9 - Give the concept of zero compression regarding IPV6. (2 Marks)
Answer: - (Page 114)
Zero-compression – series of zeroes indicated by two colons
FF0C: 0:0:0:0:0:0:B1
FF0C::B1
Q10 - Which technique is used for insertion and deletion in routing table. (2 Marks)
Answer: -
The search, insertion, and deletion operations can be finished in O(log N) time, where N is the number of
prefixes in a routing table.
Q11- Can multiple IP addresses assigned or not on different interfaces of a router. (2 Marks)
Answer: - Click here for detail
You cannot have two different IP addresses from the same network assigned to the router.7
Q12- In which process backward compatibility of 100-base- T is done? (2 Marks)
Answer: (Page 47)
100Base-T technology is backward compatible and allows the participants to negotiate a speed when
connection is established. This process is known as auto negotiation
Q13- Does OSPF only share information with an area or does it allow communication between different
areas? (2 Marks)
Answer:- (Page 141)
OSPF allows subdivision of Autonomous System into areas. The link-status information is propagated within
an area. The routes are summarized before being propagated to another area.
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