Examen 2 P2

Question 1

Message passing between a pair of processes can be supported by two message communication
operations:

Answer 1

Send and receive operations

Question 2

In this form of communication, the use of the send operation is non-blocking, the receive operation can
have blocking and non-blocking variants

Answer 2

the asynchronous communication

Question 3

We can describe this as the guaranteed to be deliver the message despite a reasonable number of
packets being dropped or lost.

Answer 3

Reliability

Question 4

Both forms of communication (UDP and TCP) use _________, which provides an endpoint for
communication between processes

Answer 4

the socket abstraction

Question 5

In this form of communication, the sending and receiving processes synchronize at every message. In
this case, both send and receive are blocking operations.

Answer 5

the synchronous communication

Question 6

Any process may make use of multiple of this elements to receive messages, but a process cannot share
them with other processes on the same computer

Answer 6

Ports

Question 7

The internet protocols, and the local port pairs define the:

Answer 7

Message destination

Question 8

This consist of transmitting a message between a socket in one process and a socket in another process.

Answer 8

Interprocess communication

Question 9

is sent by UDP is transmitted from a sending process to a receive process without acknowledgement or
retries.

Answer 9

A datagram

Question 10

Messages may be dropped occasionally, either because of a checksum error or because no buffer space
is available at the source or destination is’s called:

Answer 10

Omission failure

Question 11

This defines reliable communication in terms of two properties: integrity and validity.

Answer 11

Failure model

Question 12

This was oeiginated from BSD 4.x UNIX, provides the abstraction of a stream of bytes to which data may
be written and from which data may be read.

Answer 12

The API to the TCP protocol

Question 13

This assume that when a pair of processes are establishing a connection, one of them plays the client
role and another plays the server role, but thereafter they could be peers.

Answer 13

The API for stream communication

Question 14

The TCP protocol attempts to match the speeds of the processes that read from and write to a stream,
this is called:

Answer 14

Flow control

Question 15

These items transmitted in messages can be data values of many different types, and not all computers
store primitive values such as integers in the same order.

Answer 15

The individual primitive data

Question 16

The TCP protocol uses an acknowledgement scheme. If the sender does not receive an
acknowledgement with a time out, it retransmits the message and this is performed when:

Answer 16

There is lost messages

Question 17

This is the process of taking a collection of data items and assembling or disassembling (respectively)
into a form suitable for transmission in a message.

Answer 17

Marshalling and Unmarshalling

Question 18

They are three alternative approaches to external data representation.

Answer 18

XML, CORBAS’s, Java’s object serialization

Question 19

The first was designed for defining the appearance of web pages. the second one was designed for
writing structured documents for the Web

Answer 19

HTML and XML

Question 20

They are tagged with ‘markup’ strings. The tags are used to describe the logical structure of the data and
to associate attribute-value pairs with logical structures.

Answer 20

XML data items

Question 21

XML is ________ in the sense that users can define their own tags, in contrast to HTML, which uses a
fixed set of tags

Answer 21

Extensible

Question 22

This is a markup language that was defined by the World Wide Web Consortium (W3C) for general use
on the Web.

Answer 22

XML

Question 23

The structure of an XML document is defined by pairs of these elements enclosed in angle brackets.

Answer 23

Tags

Question 24

They define the name of values associate to tags in XML schemes.

Answer 24

XML Attributes

Question 25

This is used to enable clients to communicate with web services and for defining the interfaces and
other properties of web services.

Answer 25

XML - service

Question 26

All of the information in XML elements must be expressed as character data.
But the question is: how do we represent encrypted elements or secure hashes?

Answer 26

Binary data

Question 27

Every start tag has a matching end tag and all tags are correctly nested these are?

Answer 27

Basic rules of XML

Question 28

Every XML document must have this as its first line and must at least specify the version of XML in use
(Which is currently 1.0)

Answer 28

A prolog

Question 29

This is a set of names for a collection of element types and attributes that is referenced by a URL.

Answer 29

XML namespace

Question 30

This defines the elements and attributes that can appear in a document, how the elements are nested
and the order and number of elements, and whether an element is empty or can include text.

Answer 30

XML schema

Question 31

This protocol is based on a trio of communication primitives: doOperation, getRequest and sendReplay.

Answer 31

The request-replay protocol

Question 32

This scheme involves the management of messages requires that each message have a unique message
identifier by which it may be referenced.

Answer 32

Message Identifiers

Question 33

As its name indicates, it is a mechanism to call a procedure or a function available on a remote
computer.

Answer 33

Remote Procedure Call (RPC)

Question 34

This uses the HTTP protocol to pass information from a client computer to a server computer and uses a
small XML vocabulary to describe the nature of requests and responses.

Answer 34

XML- RPC parameters

Question 35

This specifies a procedure name and parameters in the XML request, and the server returns either a
fault or a response in the XML response

Answer 35

XML – RPC client

Question 36

Data model , request structures and response structures are parts of

Answer 36

XML - RPC

Question 37

They are a simple list of types and content - structs and arrays are the most complex types available

Answer 37

XML - RPC structure