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CUSTOMER_CODE
SMUDE
DIVISION_CODE
SMUDE
EVENT_CODE
APR2016
ASSESSMENT_CODE BC0055_APR2016
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
4255
QUESTION_TEXT
List and explain the various phases of LCP?
The Link Control Protocol goes through these phases:
•Link Establishment and Configuration Negotiation:
•Link Quality Determination:
SCHEME OF EVALUATION •Authentication:
•Network-layer Protocol Configuration Negotiation:
•Link Termination:
(Each phase with explanation carries 2 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
72416
QUESTION_TEXT
Explain various attributes of IMAP4 messages.
1.
2.
Unique identifier message attribute– (3 Marks)
Message sequence number message attribute–
SCHEME OF EVALUATION
(3 marks)
3. Flags message attribute– (4 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
121861
QUESTION_TEXT Explain generic SNMP traps.
SCHEME OF
EVALUATION
Traps are asynchronous notifications of events occurring within an
SNMP community. They can be generated both by SNMP agents and
SNMP subagents. at can be RFC architected (called enterprise-specific).
Architected traps, defined in RFC 1215, are as follows:
1.
coldStartEvent: Notifies managers that the SNMP agent is
reinitializing and that the configuration might have been altered. The
trap belongs to the RFC1213-archutectured System group, and is
therefore supported by SNMP agent.
2.
warmStartEvent: Notifies managers that the SNMP agent is
reinitializing, but there has been no alteration of the configuration.
This trap belongs to the RFC1213-archutectured System group, and
is therefore supported by SNMP agent.
3. linkDownEvent: Notifies managers that an interface has been
deactivated. Information identifying the interface is included in the
trap. This trap belongs to the RFC1213-archutectured Interface
group, and is usually supported by a TCP/IP specific subagent.
4.
linkUpEvent: Notifies managers that an interface has been
activated. Information identifying the interface is included in the
trap. This trap belongs to the RFC1213-archutectured Interface
group, and is usually supported by a TCP/IP specific subagent.
5.
snmpAuthenFailureEvent: Notifies managers that a user attempting
to access the SNMP agent. This trap belongs to the RFC1213archutectured SNMP group, and therefore is supported by a SNLP
agent.
6.
egpNeighborLossEvent: Notifies managers that a relationship with
an EGP neighbor no longer exists. Information identifying the EBP
neighbor is included in the trap. This trap belongs to the RFC1213archutectured EGP group, and therefore is usually supported by an
EGP-specific subagent or a TCP/IP specific-subagent.
7.
entSpecificEvent: This trap is a placeholder that allows SNMP
agent or subagent implementations to create enterprise-specific
traps. Traps generated by an SNMP agent are usually delivered to
managers using well known UDP port 162. However,
implementations might provide a configuration option to allow traps
to be sent to other user-determined ports. If a subagent generates
trap, the trap is not sent directly from the subagent to a manager.
Instead, the trap is over the DPI condition to the agent, who then
sends out the trap to the managers.
(10 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
121862
QUESTION_TEXT
What is a socket? Give an example.
SCHEME OF
EVALUATION
The socket interface is one of serval application programming interfaces
to the communication protocols. Designed to be a generic
communication programming interface, socket APIs were first
introduced by Berkeley software Distribution (BSD). Although it has not
been standardized, Berkeley socket API has become a de facto industry
standard abstraction for network TCP/IP socket implementation.
Consider the following terminologies:
1.
A socket is a special type of file handle, which is used by a process
to request network services from the operating system
2.
A socket address is the triple: <protocol, local–address, local port>
For example, in the TCP/IP I(version 4)suite:
<tcp, 192.168.14.234, 8080>
3.
A conversation is the communication link between two processes.
4.
An association is the 5–tuple that completely specifies the two
processes that comprise a connection:
<protocol, local–address, local–port, foreign–address, foreign–port>
In the TCP/IP (version 4) suite, the following could be a valid
association.
<tcp, 192.168.14.234, 1500, 192.168.44, 22>
5.
A half–association is either one of the following, which each
specify half of a connection:
<protocol, local–address, local–process>
Or:
<protocol, foreign–address, foreign–process>
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
121865
QUESTION_TEXT
Briefly discuss different application layer protocols
SCHEME OF
EVALUATION
Application Layer:
1.
The Hypertext Transfer Protocol(HTTP) transfers fills that make
up pages on the world wide web.
2.
The File Transfer Protocol (FTP) transfers individual files,
typically for an interactive user session.
3.
The Simple Mail Transfer Protocol (SMTP) transfers mail
messages and attachments. Additionally, the following Application
layer protocols help you use and manage TCP/IP networks.
4.
The Domain Name System(DNS) protocol resolves a host name,
such a www.cisco.com, to an IP address and copies name
information between DNS servers.
5.
The Routing information Protocol (RIP) is a protocol that routers
use to exchange routing information on an IP network.
6.
The Simple Network Management Protocol (SNMP) collects and
exchanges network management information between a network
management console and network devices such as routers, bridges
and servers.
7.
Windows Sockets and NetBIOS are examples of Application layer
interfaces for TCP/IP application.
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
121866
QUESTION_TEXT
Explain various steps involved in SMTP mail transaction flow.
1.
2.
3.
4.
5.
SCHEME OF
EVALUATION
6.
7.
The sender SMTP establishes a TCP connection with the
destination SMTP and then waits for the server to send a 220
Service ready message or 421 service not available message when
the destination is temporarily unable to proceed.
HELO is sent to which the receiver will identify itself by sending
back its domain name……………………………that it supports.
The sender now initiates the start of a mail transaction by sending a
MAIL command to the receiver…………………….the receiver
replies with a 250 OK.
The second step of the actual mail exchange consists of providing
the server SMTP with the destinations for the message……..
When all RCPT commands are sent, the sender issues a DATA
command to notify the receiver that the message contents will
follow………..sender should use to terminate the message data.
The client now sends the data line by line, ending with the 5character sequence………..went wrong
At this junction, the client now has several possible actions
*
If the sender has no more messages to send, but it can end
the connection with a QUIT command
*
If the sender has no more messages to send, but is ready to
receive messages from the other side.
*
If the sender has another message to send, it returns to step 3
and sends a new MAIL command.