1.(): a device for storing information on a computer, with a magnetic surface that records information received in electronic form.
Area
Disk
Buffer
File
2.(): a fault in a machine, especially in a computer system or program.
Debug
Bug
Fault
Default
3.work ( ) ,systems that effectively isolate an organization's internal network structurefrom an () network, such as the INTERNET is becoming increasingly popular. These firewall systemstypically act as application-layer () between networks, usually offering controlled TELNET, FTP andSMTP access. With the emergence of more sophisticated (请作此空) layer protocols designed tofacilitate global information discovery , there exists a need to provide a general () for these protocolsto transparently and securely traverse a firewall.
network
session
transmission
application
4.(): a strip at the edge of a computer screen that you use to scroll through a filewith, using a mouse.
Title bar
Tool bar
Status bar
Scroll bar
5.BGP runs over a reliable transport (). This eliminates the need to implement explicitupdate fragmentation, retransmission, acknowledgement, and (). Any authentication scheme used bythe transport protocol may be used in addition to BGp's own () mechanisms. The error notificationmechanism used in BGp () that the transport protocol supports a "graceful” close, i.e., that alloutstanding data will be delivered(请作答此空) the connection is closed.
after
before
earlier
concurrently
6.BGP runs over a reliable transport (). This eliminates the need to implement explicitupdate fragmentation, retransmission, acknowledgement, and (). Any authentication scheme used bythe transport protocol may be used in addition to BGP's own () mechanisms. The error notificationmechanism used in BGp(请作此空) that the transport protocol supports a “graceful” close, i.e., thatall outstanding data will be delivered () the connection is closed.
assumes
imagine
enactment
setting
7.BGP runs over a reliable transport () . This eliminates the need to implement explicitupdate fragmentation, retransmission, acknowledgement, and(请作此空). Any authenticationscheme used by the transport protocol may be used in addition to BGP's own () mechanisms. Theerror notification mechanism used in BGp () that the transport protocol supports a "graceful” close.i.e., that all outstanding data will be delivered () the connection is closed.
synchronization
conflict
transport
sequencing
8.BGP runs over a reliable transport(请作答此空). This eliminates the need toimplement explicit update fragmentation, retransmission, acknowledgement, and (). Anyauthentication scheme used by the transport protocol may be used in addition to BGP's own ()mechanisms. The error notification mechanism used in BGP () that the transport protocol supports a"graceful" close, i.e., that all outstanding data will be delivered () the connection is closed.
protocol
moving
machine
gateway
9.BGP runs over a reliable transport (). This eliminates the need to implement explicitupdate fragmentation, retransmission, acknowledgement, and (), Any authentication scheme used buthe transport protocol may be used in addition to BGP's own(请作答此空)mechanisms. The errornotification mechanism used in BGp () that the transport protocol supports a “graceful” close, i....that all outstanding data will be delivered () the connection is closed.
solution
authorization
authentication
auditing
10.The number of home users and small businesses that want to use the lnternet is everincreasing. The shortage of addresses is becoming a serious problem. A quick solution to this problem iscalled network address translation(NAT).NAT enables a user to have a large set of addresses () and oneaddress, or a smallset of addresses,externally. The traffic inside can use the large set; the traffic () , thesmall set. To separate the addresses used inside the home or business and the ones used for the internetthe lnternet authorities have reserved three sets of addresses as() addresses. Any organization canuse an address out of this set withoutpermission from the internet authorities. Everyone knows thatthese reserved addresses are for private networksThey are(请作此空)inside the organization, butthey are not unique globally, No router will () a packet that has one of these addresses as thedestination address.The site must have only one single connection to the global internet through arouter that runs the NAT software.
unique
observable
particular
ordinary
11.
absolutely
completely
internally
externally
12.0SPF is a link-state routing protocol, lt is designed to be run internal to a single ()system, Each OSPF router maintains an identical () describing the autonomous system's topology.From this database, a routing table is calculated by constructing a shortest-path (73)。 OSPFrecalculates routes quickly in the face of topological changes, utilizing a minimum of routing ()traffic。 OsPF provides support for equal-cost multipath, An area routing capability is provided.enabling an additional level of routing protection and a reduction in routing protocol ()。
connection
tree
decision
bitmap
13.
reject
receive
deny
forwar
14.In multipoint networks , there are tree persistence methods when a station finds achannel busy.in the 1-persistent method,after the station finds the line idle,it sends its frameimmediately.this method has the () chance of colision because two or more stations may find the lineand send their frames immediately. In the nonpersistent method , a station that has a frame to send()() the line . lf the line is idle , it sends immediately lf the line is not idle , it waits a () amount oftime and then senses the line again,The nonpersistent approach(请作此空)the chance of collisionbecause it is unlikely that two or more stations will wait the same amount of time and retry to sendsimultaneously The p-persistent approach combines the advantages of the other two strategies . ltreduces the chance of collision and improves efficiency.
increases
equalizes
reduces
cancels
15.The number of home users and small businesses that want to use the Internet is everincreasing. The shortage of addresses is becoming a serious problem, A quick solution to this problem iscalled network address translation(NAT).NAT enables a user to have a large set of addresses (诗作答此空) and one address, or a smallset of addresses,externally, The traffic inside can use the large set: thetraffic () , the small set, To separate the addresses used inside the home or business and the ones usedfor the Internet, the Internet authorities have reserved three sets of addresses as () addresses. Anyorganization can use an address out of this set withoutpermission from the Internet authorities.Everyone knows that these reserved addresses are for private networks.They are ()inside theorganization, but they are not unique globally. No router will () a packet that has one of theseaddresses as the destination address.The site must have only one single connection to the globaInternet through a router that runs the NAT software.
absolutely
completely
internally
externally
16.The number of home users and small businesses that want to use the Internet is everincreasing. The shortage of addresses is becoming a serious problem. A quick solution to this problem iscalled network address translation(NAT).NAT enables a user to have a large set of addresses ( ) and oneaddress, or a smallset of addresses,externally. The traffic inside can use the large set; the traffic ( ) , thesmall set, To separate the addresses used inside the home or business and the ones used for the Internetthe Internet authorities have reserved three sets of addresses as(请作此空) addresses. Anyorganization can use an address out of this set withoutpermission from the Internet authoritiesEveryone knows that these reserved addresses are for private networks.They are ()inside theorganization, but they are not unique globally, No router will () a packet that has one of theseaddresses as the destination address.The site must have only one single connection to the globaInternet through a router that runs the NAT software.
private
common
public
external
17.The number of home users and small businesses that want to use the Internet is everincreasing. The shortage of addresses is becoming a serious problem. A quick solution to this problem iscalled network address translation(NAT).NAT enables a user to have a large set of addresses ( ) and oneaddress, or a smallset of addresses,externally. The traffic inside can use the large set; the traffic (请作答此) , the small set, To separate the addresses used inside the home or business and the ones used for theInternet, the Internet authorities have reserved three sets of addresses as () addresses. Anyorganization can use an address out of this set withoutpermission from the internet authorities.Everyone knows that these reserved addresses are for private networks.They are ()inside theorganization, but they are not unique globally, No router will () a packet that has one of theseaddresses as the destination address.The site must have only one single connection to the globalInternet through a router that runs the NAT software.
ocal
outside
middle
around
18.The number of home users and small businesses that want to use the Internet is everincreasing. The shortage of addresses is becoming a serious problem. A quick solution to this problem iscalled network address translation(NAT).NAT enables a user to have a large set of addresses () and oneaddress, or a smallset of addresses,externally. The traffic inside can use the large set; the traffic () , thesmall set, To separate the addresses used inside the home or business and the ones used for the internetthe Internet authorities have reserved three sets of addresses as () addresses. Any organization canuse an address out of this set withoutpermission from the internet authorities, Evervone knows thatthese reserved addresses are for private networks.They are () inside the organization, but they are notunigue globally. No router will (请作此空)a packet that has one of these addresses as the destinationaddress.The site must have only one single connection to the global internet through a router that runsthe NAT software.
reject
receive
deny
forward
19.() : a way of storing information in a computer in which the most recently storeditem is the first to be retrieved (= found or got back)
Data
Database
Buffer
Stack
20.IP multicasting is a set of technologies that enable efficient delivery of data to manylocations on a network, Rather than making multiple copies of a message intended to be distributed tomultiple recipients at the () of origin of a message, multicasting initially sends just one () and doesnot copy it to the individual recipients until it reaches the closest common point on the network, thereby()the bandwidth consumed. Network performance is significantly () because it isn’t bogged downwith the processing and transmission of several large data files; each receiving computer doesn’t haveto ()the transmitting server for the file.
1o0p
find
search
query
21.0pen Shortest Path First (OSPF) was designed as an () gateway protocol, for use in an autonomous system such as a local areanetwork (LAN). lt implements Dijkstra's algorithm, also known as the(清作答此空)path first algorithmAs a link-state routing protocol it was based on the link-state algorithm developed for the ARPANET in1980 and the ls-lS routing protocol. OsPF was first standardised in 1989 as RFc 1131, which is nowknown as OspF version 1.Routing protocols like OSpF calculate the shortest route to a destinationthrough the network based on an algorithm. The first routing protocol that was widely implemented, the(), calculated the shortest route based on hops, that is the number of routers that an lp packet had totraverse to reach the destination host. Rlp successfully implemented dynamic routing, where routingtables change if the network topology changes. But RlP did not adapt its routing according to changingnetwork conditions, such as data-transfer rate. Demand grew for a dynamic routing protocol that couldcalculate the fastest route to a destination. () was developed so that the shortest path through anetwork was calculated based on the cost of the route, taking into account bandwidth, delay and loadTherefore OSpF undertakes route cost calculation on the basis of link-cost parameters, which can beweighted by the administrator. OSpF was quickly adopted because it became known for reliablycalculating routes through large and complex local area networks.As a link state routing protocol, OSpfmaintains link state ( ) , which are really network topology maps, on every router on which it isimplemented. The state of a given route in the network is the cost, and OSpF algorithm allows everyrouter to calculate the cost of the routes to any given reachable destination. Unless the administratoihas made a configuration, the link cost of a path connected to a router is determined by the bit rate (iGbit/s, 10 Gbit/s, etc) of the interface. A router interface with OSpF will then advertise its link cost toneighbouring routers through multicast, known as the hello procedure. All routers with OSpFimplementation keep sending hello packets, and thus changes in the cost of their links become known toneighbouring routers. The information about the cost of a link, that is the speed of a point to pointconnection between two routers, is then cascaded through the network because OSpF routers advertisethe information they receive from one neighbouring router to all other neighbouring routers. Thisprocess of flooding link state information through the network is known as synchronisation. Based onthis information, all routers with OSPF implementation continuously update their link state databaseswith information about the network topology and adjust their routing tables.OSpF has become apopular dynamic routing protocol. Other commonly used dynamic routing protocols are the Rlp and theBorder Gateway Protocol (BGP). Today routers support at least one interior gateway protocol toadvertise their routing tables within a local area network. Frequently implemented interior gatewayprotocols besides OSPF are Rlp, is-is, and the proprietary Interior Gateway Routing Protocol (lGRP) byeisco.
shortest
longest
first
begin
22.work ( ) ,systems that effectively isolate an organization's internal network structurefrom an () network, such as the INTERNET is becoming increasingly popular. These firewall systemstypically act as application-layer (请作答此空) between networks, usually offering controlled TELNET,FTP, and SMTP access. With the emergence of more sophisticated ( ) layer protocols designed tofacilitate global information discovery , there exists a need to provide a general () for these protocolsto transparently and securely traverse a firewall.
hosts
routers
gateways
offices
23.The Hypertext Transfer Protocol , the Web's () protocol , is at the heart of the Web.HTTP is implemented in two programs :a (请作此空) program and a server program . The clientprogram and server program executing on different end systems , talk to each other by () HTTPmessages . HTTp defines how Web clients request Web pages from servers and how servers transfer webpages to clients . when a user () a web page , the browser sends http request messages for the objects inthe page to the server . The server () the requests and responds with http response messages thatcontain the objects .
hoste
user
client
guest
24.CSMA, although more efficient than ALOHA or slotted ALOHA, still has one glaringinefficiency, lf the medium is busy, the station will wait for a random amount of time. When two framescollide, the medium remains(请作答此空) for the duration of transmission of both damaged frames.The use of random delays reduces the probability of ().For () frames, compared to propagation timethe amount of wasted capacity can be considerable, This waste can be reduced if a station continues toisten to the medium while ( ) .The maximum utilization depends on the length of the frame and on the() time; the longer the frames or the shorter the propagation time, the higher the utilization.
convenient
inconvenient
usable
unusable
25.The Internet is based on connectionless end-to-end packet service, whichtraditionally provided best-effort means of data(请作此空)using the Transmission Control ProtocolInternet Protocol suite. Although the ( ) design gives the Internet its flexibility and robustness, itspacket dynamics also make it prone to congestion problems,especially at( ) that connect networks otwidely different bandwidths.The initial Qos function set was for internet hosts.One major problem withexpensive wide-area ( ) links is the excessive overhead due to small Transmission Control Protocolpackets created by applications such as telnet and rlogin.The Nagle (), which solves this issue,isnow supported by all lp host implementations.
transformation
transportation
processing
progressing
26.0pen Shortest Path First (OSPF) was designed as an(清作答此空)gateway protocol, for use in an autonomous system such as a localarea network (LAN). lt implements Dijkstra's algorithm, also known as the () path first algorithm. As ilink-state routing protocol it was based on the link-state algorithm developed for the ARPANET in 1980and the ls-ls routing protocol. OsPF was first standardised in 1989 as RFc 1131, which is now known asOSPF version 1.Routing protocols like OsPF calculate the shortest route to a destination through thenetwork based on an algorithm. The first routing protocol that was widely implemented, the (),calculated the shortest route based on hops, that is the number of routers that an lp packet had totraverse to reach the destination host. RlP successfully implemented dynamic routing, where routingtables change if the network topology changes. But RlP did not adapt its routing according to changingnetwork conditions, such as data-transfer rate. Demand grew for a dynamic routing protocol that couldcalculate the fastest route to a destination. () was developed so that the shortest path through anetwork was calculated based on the cost of the route, taking into account bandwidth, delay and loadTherefore OSPF undertakes route cost calculation on the basis of link-cost parameters, which can beweighted by the administrator. OSPF was quickly adopted because it became known for reliablycalculating routes through large and complex local area networks.As a link state routing protocol, OSPFmaintains link state ( ) , which are really network topology maps, on every router on which it isimplemented. The state of a given route in the network is the cost, and OSPF algorithm allows everyrouter to calculate the cost of the routes to any given reachable destination. Unless the administratorhas made a configuration, the link cost of a path connected to a router is determined by the bit rate (1Gbit/s, 10 Gbit/s, etc) of the interface. A router interface with OsPF will then advertise its link cost toneighbouring routers through multicast, known as the hello procedure. All routers with OSPFimplementation keep sending hello packets, and thus changes in the cost of their links become known toneighbouring routers. The information about the cost of a link, that is the speed of a point to pointconnection between two routers, is then cascaded through the network because OSPF routers advertisethe information they receive from one neighbouring router to all other neighbouring routers. Thisprocess of flooding link state information through the network is known as synchronisation. Based onthis information, all routers with OSPF implementation continuously update their link state databaseswith information about the network topology and adjust their routing tables.OsPF has become apopular dynamic routing protocol. Other commonly used dynamic routing protocols are the RlP and theBorder Gateway Protocol (BGP). Today routers support at least one interior gateway protocol toadvertise their routing tables within a local area network. Freguently implemented interior gatewayprotocols besides OSPF are Rlp, is-is, and the proprietary Interior Gateway Routing Protocol (lGRP) byCisco.
exterior
interior
border
routing
27.0SPF is a link-state routing protocol, it is designed to be run internal to a single()system, Each OsPF router maintains an identical () describing the autonomous system’stopology. From this database, a routing table is calculated by constructing a shortest-path ().OSPFrecalculates routes quickly in the face of topological changes, utilizing a minimum of routing ()traffic, OsPF provides support for equal-cost multipath, An area routing capability is provided,enabling an additional level of routing protection and a reduction in routing protocol ()。
autonomous
network
computer
server
28.IP multicasting is a set of technologies that enable efficient delivery of data to many locations on anetwork, Rather than making multiple copies of a message intended to be distributed to multiplerecipients at the () of origin of a message, multicasting initially sends just one () and does not copyit to the individual recipients until it reaches the closest common point on the network, thereby () thebandwidth consumed. Network performance is significantly () because it isn’t bogged down with theprocessing and transmission of several large data files; each receiving computer doesn’t have tothe transmitting server for the file.
extending
minimizing
demolishing
reducing
29.The File Transfer Protocol (FTP) is a standard network protocol used for the transferof computer () between a client and server on a computer network.FTP is built on a () modelarchitecture using separate control and data connections between the cient and the server. FTp usersmay authenticate themselves with a() sign-in protocol, normally in the form of a username andpassword, but can connect anonymously if the server is configured to allow it, For secure transmissionthat protects the username and password, and encrypts the content, FTp is often secured with SSL/TLS(FTPS) or replaced with ssH File Transfer Protocol (SFTP).The first FTP client applications were(请作答此空)programs developed before operating systems had graphical user interfaces, and are still shippedwith most Windows, Unix, and Linux operating systems. Many FTp clients and automation utilities havesince been developed for desktops, servers, mobile devices, and hardware, and FTp has beenincorporated into productivity applications, such as HTML editors.FTP may run in () mode, whichdetermines how the data connection is established. In both cases, the client creates a Tcp controlconnection from a random, usually an unprivileged, port N to the FTP server command port 21.in activemode, the client starts listening for incoming data connections from the server on port M. lt sends theFTP command PORT M to inform the server on which port it is listening. The server then initiates a datachannel to the client from its port 20, the FTp server data port.In situations where the client is behind afirewall and unable to accept incoming Tcp connections, passive mode may be used. in this mode, theclient uses the control connection to send a PAsV command to the server and then receives a server ipaddress and server port number from the server, which the client then uses to open a data connectionfrom an arbitrary client port to the server lp address and server port number received.Both modes wereupdated in September 1998 to support lPv6. Further changes were introduced to the passive mode atthat time, updating it to extended passive mode.
command-line
graphical
automation
productivity
30.In multipoint networks , there are tree persistence methods when a station finds achannel busy.in the 1-persistent method,after the station finds the line idle,it sends its frameimmediately.this method has the(请作此空)chance of collision because two or more stations mayfind the line ( ) and send their frames immediately. In the nonpersistent method , a station that has aframe to send ( ) the line . lf the line is idle , it sends immediately lf the line is not idle , it waits a()amount of time and then senses the line again,The nonpersistent approach ( ) the chance of collisionbecause it is unlikely that two or more stations will wait the same amount of time and retry to sendsimultaneously The p-persistent approach combines the advantages of the other two strategies . ltreduces the chance of collision and improves efficiency.
the lowest
the highest
possible
no
31.The File Transfer Protocol (FTP) is a standard network protocol used for the transferof computer () between a client and server on a computer network.FTp is built on a () modelarchitecture using separate control and data connections between the client and the server. FTp usersmay authenticate themselves with a () sign-in protocol, normally in the form of a username andpassword, but can connect anonymously if the server is configured to allow it, For secure transmissionthat protects the username and password, and encrypts the content, FTp is often secured with SSL/TLs(FTPS) or replaced with ssH File Transfer Protocol (SFTP).The first FTP client applications were ()programs developed before operating systems had graphical user interfaces, and are still shipped withmost Windows, Unix, and Linux operating systems. Many FTP clients and automation utilities have sincebeen developed for desktops, servers, mobile devices, and hardware, and FTp has been incorporatedinto productivity applications, such as HTML editors.FTP may run in(请作此空)mode, whichdetermines how the data connection is established. in both cases, the client creates a Tcp controlconnection from a random, usually an unprivileged, port N to the FTp server command port 21.in activemode, the client starts listening for incoming data connections from the server on port M. it sends theFTP command PORT M to inform the server on which port it is listening. The server then initiates a datachannel to the client from its port 20, the FTp server data port.In situations where the client is behind afirewall and unable to accept incoming Tcp connections, passive mode may be used. in this mode, theclient uses the control connection to send a PASV command to the server and then receives a server lpaddress and server port number from the server, which the client then uses to open a data connectionfrom an arbitrary client port to the server lp address and server port number received.Both modes wereupdated in September 1998 to support lPv6. Further changes were introduced to the passive mode atthat time, updating it to extended passive mode.
system
Ractive
passive
active or passive
32.Secure Shell($SH) is a cryptographic network protocol for () remote login and other secure network services over an(请作答此空)network.The standard () port for ssH is 22. The best known example application is forremote login to computer systems by users.SSH provides a secure channel over an insecured network in a () architecture, connecting an $sH clientapplication with an ssH server, Common applications include remote command-line login and remotecommand execution, but any network service can be secured with $sH. The protocol specification distinguishes between two major versions, referred to as ssH-1 and ssH-2.The most visible application of the protocol is for access to shell accounts on () operating systems, butit sees some limited use on Windows as well. In 2015, Microsoft announced that they would includenative support for $SH in a future release.
secure
insecure
internet
internal
33.Buffer ()cause many software weaknesses and, therefore, are the basis ofmalicious exploits.
Interrupt
Default
Underflow
Overflow
34.ip multicasting is a set of technologies that enable efficient delivery of data to manylocations on a network, Rather than making multiple copies of a message intended to be distributed tomultiple recipients at the () of origin of a message, multicasting initially sends just one () and doesnot copy it to the individual recipients until it reaches the closest common point on the network, thereby() the bandwidth consumed. Network performance is significantly () because it isn’t bogged downwith the processing and transmission of several large data files; each receiving computer doesn’t haveto()the transmitting server for the file.
dropped
prove
improve
upgrade
35.
local
outside
middle
aroun
36.The Hypertext Transfer Protocol , the Web's () protocol , is at the heart of the Web.HTTP is implemented in two programs : a () program and a server program . The client program andserver program executing on different end systems , talk to each other by () HTTP messages . HTTPdefines how Web clients request Web pages from servers and how servers transfer web pages to clientswhen a user () a web page , the browser sends http request messages for the objects in the page to theserver . The server (青作答比空) the reguests and responds with http response messages that contain theobjects .
declines
deletes
edits
receives
37.CSMA, although more efficient than ALOHA or slotted ALOHA, still has one glaringinefficiency. lf the medium is busy, the station will wait for a random amount of time. When two framescollide, the medium remains () for the duration of transmission of both damaged frames. The use ofrandom delays reduces the probabilityof(请作此空),For ()frames, compared to propagation timethe amount of wasted capacity can be considerable. This waste can be reduced if a station continues tolisten to the medium while ( ) .The maximum utilization depends on the length of the frame and on the() time; the longer the frames or the shorter the propagation time, the higher the utilization.
transmission
collisions
transportation
reception
38.The Internet is based on connectionless end-to-end packet service, whichtraditionally provided best-effort means of data () using the Transmission Control Protocol/internetProtocol suite. Although the () design gives the internet its flexibility and robustness, its packetdynamics also make it prone to congestion problems,especially at () that connect networks of widelydifferent bandwidths.The initial Qos function set was for internet hosts.One major problem withexpensive wide-area ( ) links is the excessive overhead due to small Transmission Control Protocolpackets created by applications such as telnet and rlogin,The Nagle(请作此空), which solves thisissue,is now supported by all lp host implementations.
technology
problem
structure
algorithm
39.Together with the network layer,the transport layer is the heart of the protocol ().Thenetwork layer provides end-to-end () delivery using datagrams or virtual circuits.The transport layerbuilds on the network layer to provide data transport from a process on a (请作此空) machine to aprocess on a destination machine with a desired level of reliability that is independent of the physical (currently in use.lt provides the abstractions that applications nedd to use the network..without the (layer,the whole concept of layered protocols would make little sense.
connection
terminal
source
destination
40.The File Transfer Protocol (FTP) is a standard network protocol used for the transferfcomputer(请作答此空)between a client and server on a computer network.FTp is built on a()hodel architecture using separate control and data connections between the client and the server. FTPIsers may authenticate themselves with a () sign-in protocol, normally in the form of a username andjassword, but can connect anonymously if the server is configured to allow it. For secure transmissioniat protects the username and password, and encrypts the content, FTp is often secured with SSL/TLsFTPS) or replaced with ssH File Transfer Protocol (SFTP).The first FTP client applications were()rograms developed before operating systems had graphical user interfaces, and are still shipped withhost Windows, Unix, and Linux operating systems. Many FTP clients and automation utilities have sinceeen developed for desktops, servers, mobile devices, and hardware, and FTp has been incorporatedito productivity applications, such as HTML editors.FTP may run in () mode, which determines howhe data connection is established, in both cases, the client creates a TCp control connection from aandom, usually an unprivileged, port N to the FTp server command port 21.in active mode, the clienttarts listening for incoming data connections from the server on port M. lt sends the FTp commandORT M to inform the server on which port it is listening. The server then initiates a data channel to thelient from its port 20, the FTp server data port.In situations where the client is behind a firewall andnable to accept incoming Tcp connections, passive mode may be used. in this mode, the client uses theontrol connection to send a PAsV command to the server and then receives a server IP address ander'ver port number from the server, which the client then uses to open a data connection from anrbitrary client port to the server lP address and server port number received.Both modes were updatedSeptember 1998 to support lPv6, Further changes were introduced to the passive mode at that time.pdating it to extended passive mode.
network
proqrams
connections
files
41.A management domain typically contains a large amount of managementinformation. Each individual item of (71) information is an instance of a managed object type. Thedefinition of a related set of managed () types is contained in a Management Information Base (MlB)module. Many such MlB modules are defined. For each managed object type it describes, a MlB (73)defines not only the semantics and syntax of that managed object type, but also the method ofidentifying an individual instance so that multiple (74) of the same managed object type can bedistinguished. Typically, there are many instances of each managed object (75)within a managementdomain
path
object
route
packet
42.Traditional network layer packet forwarding relies on the information provided bynetwork layer () protocols, or static routing, to make an independent () decision at each hop withinthe network, The forwarding () is based solely on the destination (本题) IP address. All packets for thesame destination follow the same path across the network if no other equal-cost paths exist, Whenever arouter has two equal-cost () toward a destination, the packets toward the destination might take oneor both of them, resulting in some degree of load sharing.
paths
distance
speed
session
43.A management domain typically contains a large amount of managementinformation. Each individual item of (71) information is an instance of a managed object type. Thedefinition of a related set of managed (72) types is contained in a Management Information Base (MlB)module. Many such MlB modules are defined. For each managed object type it describes, a MlB (73defines not only the semantics and syntax of that managed object type, but also the method ofidentifying an individual instance so that multiple (74) of the same managed object type can bedistinguished. Typically, there are many instances of each managed object () within a managementdomain
device
state
type
packet
44.Currently 94% of Web users use either internet Explorer or Firefox, but recently somenew (71) have been developed that are beginning to attract attention, The browser Opera is becomingvery (72) because of its speed, it is currently the world’s fastest browser, and because it is muchsmaller (73) existing browsers it can almost fit on a single diskette). it can also (74) the last Webpage you visited, so the next time you surf, you can start where you left off, And like the big two, youcan get it for free; the catch is that you have to watch blinking ads in one corner, or pay $40 for the ad.free (75)of opera.
think
read
write
remember
45.0SPF is a link-state routing protocol, lt is designed to be run internal to a single ()system, Each OSPF router maintains an identical (72) describing the autonomous system'stopology, From this database, a routing table is calculated by constructing a shortest-path (). OsPFrecalculates routes quickly in the face of topological changes, utilizing a minimum of routing()traffic, OSPF provides support for equal-cost multipath, An area routing capability is provided,enabling an additional level of routing protection and a reduction in routing protocol ()。
tree
table
database
recor
46.A management domain typically contains a large amount of managementinformation, Each individual item of (71) information is an instance of a managed object type. Thedefinition of a related set of managed (72) types is contained in a Management Information Base (MlB)module. Many such MlB modules are defined. For each managed object type it describes, a MlB (73)defines not only the semantics and syntax of that managed object type, but also the method ofidentifying an individual instance so that multiple () of the same managed object type can bedistinguished. Typically, there are many instances of each managed obiect (75)within a managementdomain
packets
searches
states
instances
47.Currently 94% of Web users use either Internet Explorer or Firefox, but recently somenew (71) have been developed that are beginning to attract attention, The browser Opera is becomingvery (72) because of its speed, it is currently the world’s fastest browser, and because it is muchsmaller (73)existing browsers (it can almost fit on a single diskette). lt can also (74) the last Webpage you visited, so the next time you surf, you can start where you left off. And like the big two, youcan get it for free, the catch is that you have to watch blinking ads in one corner, or pay $40 for the adfree (75)of opera.
popular
notorious
wonderful
common
48.Traditional network layer packet forwarding relies on the information provided bynetwork layer (本题)protocols, or static routing, to make an independent () decision at each hopwithin the network, The forwarding () is based solely on the destination () iP address. All packets forthe same destination follow the same path across the network if no other equal-cost paths exist.Whenever a router has two equal-cost () toward a destination, the packets toward the destinationmight take one or both of them, resulting in some degree of load sharing
switching
singnaling
routing
session
49.The File Transfer Protocol (FTP) is a standard network protocol used for the transferof computer () between a client and server on a computer network.FTP is built on a(请作答此空)model architecture using separate control and data connections between the client and the server. FTpusers may authenticate themselves with a() sign-in protocol, normally in the form of a username andpassword, but can connect anonymously if the server is configured to allow it, For secure transmissionthat protects the username and password, and encrypts the content, FTP is often secured with SSL/TLs(FTPS) or replaced with ssH File Transfer Protocol (SFTP).The first FTP client applications were()programs developed before operating systems had graphical user interfaces, and are still shipped withmost Windows, Unix, and Linux operating systems. Many FTP clients and automation utilities have sincebeen developed for desktops, servers, mobile devices, and hardware, and FTp has been incorporatedinto productivity applications, such as HTML editors.FTP may run in () mode, which determines howthe data connection is established. in both cases, the client creates a Tcp control connection from arandom, usually an unprivileged, port N to the FTP server command port 21.in active mode, the clientstarts listening for incoming data connections from the server on port M. it sends the FTp commandPORT M to inform the server on which port it is listening, The server then initiates a data channel to theclient from its port 20, the FTp server data port.in situations where the client is behind a firewall andunable to accept incoming Tcp connections, passive mode may be used. in this mode, the client uses thecontrol connection to send a PAsV command to the server and then receives a server lP address andserver port number from the server, which the client then uses to open a data connection from anarbitrary client port to the server ip address and server port number received.Both modes were updatedin September 1998 to support lPv6. Further changes were introduced to the passive mode at that time.updating it to extended passive mode.
browser-server
user- server
client-server
business -customer
50.Secure shell (SsH) is a cryptographic network protocol for () remote login and other secure network services over an()network.The standard (请作此空) port for ssH is 22. The best known example application is forremote login to computer systems by users.SSH provides a secure channel over an insecured network in a () architecture, connecting an SSH clientapplication with an $sH server,. Common applications include remote command-line login and remotecommand execution, but any network service can be secured with SsH. The protocol specification distinguishes between two major versions, referred to as ssH-1 and ssH-2.The most visible application of the protocol is for access to shell accounts on () operating systems, butit sees some limited use on Windows as well. In 2015, Microsoft announced that they would includenative support for SSH in a future release.
ICMP
IGMP
TCP