ITNv7 Modules 14 - 15: Network Application Communications Exam
What are three responsibilities of the transport layer? (Choose three.)
- meeting the reliability requirements of applications, if any - multiplexing multiple communication streams from many users or applications on the same network - identifying the applications and services on the client and server that should handle transmitted data The transport layer has several responsibilities. Some of the primary responsibilities include the following: Tracking the individual communication streams between applications on the source and destination hosts. Segmenting data at the source and reassembling the data at the destination. Identifying the proper application for each communication stream through the use of port numbers. Multiplexing the communications of multiple users or applications over a single network. Managing the reliability requirements of applications
A client creates a packet to send to a server. The client is requesting telnet service. What number will be used as the destination port number in the sending packet?
23
A PC that is communicating with a web server has a TCP window size of 6,000 bytes when sending data and a packet size of 1,500 bytes. Which byte of information will the web server acknowledge after it has received three packets of data from the PC?
4501
Which scenario describes a function provided by the transport layer?
A student has two web browser windows open in order to access two web sites. The transport layer ensures the correct web page is delivered to the correct browser window. The source and destination port numbers are used to identify the correct application and window within that application.
What is an example of network communication that uses the client-server model?
A workstation initiates a DNS request when the user types www.cisco.com in the address bar of a web browser. When a user types a domain name of a website into the address bar of a web browser, a workstation needs to send a DNS request to the DNS server for the name resolution process. This request is a client/server model application. The eMule application is P2P. Sharing a printer on a workstation is a peer-to-peer network. Using ARP is just a broadcast message sent by a host.
Which flag in the TCP header is used in response to a received FIN in order to terminate connectivity between two network devices?
ACK In a TCP session, when a device has no more data to send, it will send a segment with the FIN flag set. The connected device that receives the segment will respond with an ACK to acknowledge that segment. The device that sent the ACK will then send a FIN message to close the connection it has with the other device. The sending of the FIN should be followed with the receipt of an ACK from the other device.
What do the client/server and peer-to-peer network models have in common?
Both models support devices in server and client roles. In both the client/server and peer-to-peer network models, clients and servers exist. In peer-to-peer networks, no dedicated server exists, but a device can assume the server role to provide information to a device serving in the client role.
What is true about the Server Message Block protocol?
Clients establish a long term connection to servers. The Server Message Block protocol is a protocol for file, printer, and directory sharing. Clients establish a long term connection to servers and when the connection is active, the resources can be accessed. Every SMB message has the same format. The use of SMB differs from FTP mainly in the length of the sessions. SMB messages can authenticate sessions.
A manufacturing company subscribes to certain hosted services from its ISP. The services that are required include hosted world wide web, file transfer, and e-mail. Which protocols represent these three key applications? (Choose three.)
FTP HTTP SMTP The ISP uses the HTTP protocol in conjunction with hosting web pages, the FTP protocol with file transfers, and SMTP with e-mail. DNS is used to translate domain names to IP addresses. SNMP is used for network management traffic. DHCP ic commonly used to manage IP addressing.
Which three protocols operate at the application layer of the TCP/IP model? (Choose three.)
FTP POP3 DHCP FTP, DHCP, and POP3 are application layer protocols. TCP and UDP are transport layer protocols. ARP is a network layer protocol.
Which three fields are used in a UDP segment header? (Choose three.)
Length Source Port Checksum A UDP header consists of only the Source Port, Destination Port, Length, and Checksum fields. Sequence Number, Acknowledgment Number, and Window Size are TCP header fields.
Which applications or services allow hosts to act as client and server at the same time?
P2P applications P2P applications allow the clients to behave as servers if needed. When using authentication services, email exchange, and client/server applications, one host acts as server and the other acts as client at all times.
Which two characteristics are associated with UDP sessions? (Choose two.)
Received data is unacknowledged. Destination devices receive traffic with minimal delay. TCP: Provides tracking of transmitted data segments· Destination devices will acknowledge received data.· Source devices will retransmit unacknowledged data. UDP: Destination devices will not acknowledge received data· Headers use very little overhead and cause minimal delay.
Which three application layer protocols use TCP? (Choose three.)
SMTP FTP HTTP Some protocols require the reliable data transport that is provided by TCP. In addition, these protocols do not have real time communication requirements and can tolerate some data loss while minimizing protocol overhead. Examples of these protocols are SMTP, FTP, and HTTP.
STEP 2
Server sends ACK
STEP 3
Server sends FIN
Which three statements describe a DHCP Discover message? (Choose three.)
The destination IP address is 255.255.255.255. The message comes from a client seeking an IP address. All hosts receive the message, but only a DHCP server replies. When a host configured to use DHCP powers up on a network it sends a DHCPDISCOVER message. FF-FF-FF-FF-FF-FF is the L2 broadcast address. A DHCP server replies with a unicast DHCPOFFER message back to the host.
Which three statements characterize UDP? (Choose three.)
UDP provides basic connectionless transport layer functions. UDP relies on application layer protocols for error detection. UDP is a low overhead protocol that does not provide sequencing or flow control mechanisms. UDP is a simple protocol that provides the basic transport layer functions. It has much lower overhead than TCP because it is not connection-oriented and does not offer the sophisticated retransmission, sequencing, and flow control mechanisms that provide reliability.
What is a characteristic of UDP?
UDP reassembles the received datagrams in the order they were received. UDP has no way to reorder the datagrams into their transmission order, so UDP simply reassembles the data in the order it was received and forwards it to the application.
Which two fields are included in the TCP header but not in the UDP header? (Choose two.)
Window Sequence number The sequence number and window fields are included in the TCP header but not in the UDP header.
Which OSI layer provides the interface between the applications used to communicate and the underlying network over which messages are transmitted?
application The application layer is the layer that is closest to the end user and provides the interface between the underlying network and the applications used to communicate.
Which layer in the TCP/IP model is used for formatting, compressing, and encrypting data?
application The application layer of the TCP/IP model performs the functions of three layers of the OSI model - application, presentation, and session. The application layer of the TCP/IP model is the layer that provides the interface between the applications, is responsible for formatting, compressing, and encrypting data, and is used to create and maintain dialogs between source and destination applications.
Which two types of applications are best suited for UDP? (Choose two.)
applications that handle reliability themselves applications that can tolerate some data loss, but require little or no delay Applications that can tolerate some data loss, require a simple request and reply, and handle reliability themselves are best suited for UDP. UDP has low overhead and no requirement of reliability. TCP provides services for reliability, controlling data flow, and the reordering of segments.
STEP 4
client sends ACK
A client application needs to terminate a TCP communication session with a server. Place the termination process steps in the order that they will occur. STEP 1
client sends FIN
Which networking model is being used when an author uploads one chapter document to a file server of a book publisher?
client/server In the client/server network model, a network device assumes the role of server in order to provide a particular service such as file transfer and storage. In the client/server network model, a dedicated server does not have to be used, but if one is present, the network model being used is the client/server model. In contrast, a peer-to-peer network does not have a dedicated server.
What are two characteristics of peer-to-peer networks? (Choose two.)
decentralized resources resource sharing without a dedicated server Peer-to-peer networks have decentralized resources because every computer can serve as both a server and a client. One computer might assume the role of server for one transaction while acting as a client for another transaction. Peer-to-peer networks can share resources among network devices without the use of a dedicated server.
In what networking model would eDonkey, eMule, BitTorrent, Bitcoin, and LionShare be used?
peer-to-peer In a peer-to-peer networking model, data is exchanged between two network devices without the use of a dedicated server. Peer-to-peer applications such as Shareaz, eDonkey, and Bitcoin allow one network device to assume the role of server, while one or more other network devices assume the role of client using the peer-to-peer application.
What kind of port must be requested from IANA in order to be used with a specific application?
registered port Registered ports (numbers 1024 to 49151) are assigned by IANA to a requesting entity to use with specific processes or applications. These processes are primarily individual applications that a user has chosen to install, rather than common applications that would receive a well-known port number. For example, Cisco has registered port 1985 for its Hot Standby Routing Protocol (HSRP) process.
What is a key characteristic of the peer-to-peer networking model?
resource sharing without a dedicated server The peer-to-peer (P2P) networking model allows data, printer, and resource sharing without a dedicated server.
What information is used by TCP to reassemble and reorder received segments?
sequence numbers At the transport layer, TCP uses the sequence numbers in the header of each TCP segment to reassemble the segments into the correct order.
Which three layers of the OSI model provide similar network services to those provided by the application layer of the TCP/IP model? (Choose three.)
session layer application layer presentation layer. The three upper layers of the OSI model, the session, presentation, and application layers, provide application services similar to those provided by the TCP/IP model application layer. Lower layers of the OSI model are more concerned with data flow.
Which factor determines TCP window size?
the amount of data the destination can process at one time Window is the number of bytes that the sender will send prior to expecting an acknowledgement from the destination device. The initial window is agreed upon during the session startup via the three-way handshake between source and destination. It is determined by how much data the destination device of a TCP session is able to accept and process at one time.
What is the function of the HTTP GET message?
to request an HTML page from a web server There are three common HTTP message types: GET - used by clients to request data from the web serverPOST - used by clients to upload data to a web serverPUT - used by clients to upload data to a web server
In what two situations would UDP be better than TCP as the preferred transport protocol? (Choose two.)
when a faster delivery mechanism is needed when applications do not need to guarantee delivery of the data UDP is a very simple transport layer protocol that does not guarantee delivery. Devices on both ends of the conversation are not required to keep track of the conversation. UDP is used as the transport protocol for applications that need a speedy, best-effort delivery.