To compete in today's fast-paced competitive environment, organizations are increasingly allowing contractors, partners, visitors and guests to access their internal enterprise networks. These users may connect to the network through wired ports in conference rooms or offices, or via wireless access points. In allowing this open access for third parties, LANs become ______. Third parties can introduce risk in a variety of ways from connecting with an infected laptop to unauthorized access of network resources to ______ activity. For many organizations, however, the operational complexity and costs to ensure safe third party network access have been prohibitive. Fifty-two percent of surveyed CISOs state that they currently use a moat and castle's security approach, and admit that defenses inside the perimeter are weak. Threats from internal users are also increasingly a cause for security concerns. Employees with malicious intent can launch ______ of service attacks or steal ______ information by snooping the network. As they access the corporate network, mobile and remote users inadvertently can infect the network with ______ and worms acquired from unprotected public networks. Hackers masquerading as internal users can take advantage of weak internal security to gain access to confidential information.
WLANs are increasingly popular because they enable cost-effective connections amongpeople, applications and data that were not possible, or not cost-effective, in the past.For example, WLAN-based applications can enable fine-grained management of supply and distribution ______ to improve their efficiency and reduce ______. WLANs can also enable entirely new business processes. To cite but one example, hospitals are using WLAN-enabled point-of-care applications to reduce errors and improve overall ______ care.WLAN management solutions provide a variety of other benefits that can be substantial but difficult to measure. For example, they can protect corporate data by preventing ______ through rogue access points. They help control salary costs, by allowing IT staffs to manage larger networks without adding staff. And they can improve overall network management by integrating with customers' existing systems, such as OpenView. Fortunately, it isn't necessary to measure these benefits to justify investing in WLAN management solutions, which can quickly pay for themselves simply by minimizing time-consuming ______ and administrative chores.
Pharming is a scamming practice in which malicious code is installed on a personal computer or server, misdirecting users to ______ Web sites without their knowledge or consent. Pharming has been called "phishing without a lure". In phishing, the perpetrator sends out legitimate-______ e-mails, appearing to come from some of the Web's most popular sites, in an effort to obtain personal and financial information from individual recipients. But in pharming, larger numbers of computer users can be ______ because it is not necessary to target individuals one by one and no conscious action is required on the part of the victim.In one form of pharming attack, code sent in an e-mail modifies local host files on a personal computer. The host files convert URLs into the number strings that the computer uses to access Web sites. A computer with a compromised host file will go to the fake Web site even if a user types in the correct Internet address or clicks on an affected ______ entry. Some spyware removal programs can correct the corruption, but it frequently recurs unless the user changes browsing ______
When the system upon which a transport entity is running fails and subsequently reatarts, the ______ information of all active connections is lost. The affected connections become half-open, as the side that did not fail does not yet realize the promble. The still active side of a half-open connections using a ______ timer. This timermeasures the time transport machine will continue to await an ______ of a transmitted segment after the segment has been retransmitted the maximum number of times. When the timer ______, the transport entity assumes that either the other transport entity or the intervening network has failed. As a result, the timer closes the connection, and signals an abnormal close to the TS user. In the event that a transport entity fails and quickly restart, half-open connections can be teminated more quickly by the use of the RST segment. The failed side returns an RSTi to every segment i that it receives. When the RSTi reaches the other side, it must be checked for validity dased on the ______ number i, as the RST could be in response to an old segment .If the reset is valid, the transport entity performs an abnormal termination.
______ is used to ensure the confidentiality, integrity and authenticity of the two end points in the private network. ______, an application-layer protocol, authenticates each peer in an IPSec transaction. IKE negotiates security policy, determining which algorithm may be used to set up the tunnel. It also handles the exchange of session keys used for that one transaction. Networks that use ______ to secure data traffic can automatically authenticate devices by using by using ______, which verify the identities of the two users who are sending information back and forth. IPSec can be ideal way to secure data in large networks that require secure connections among many devices. Users deploying IPSec can ______ their network infrastructure without affecting the applications on individual computer. The protocol suite is available as a software-only upgrade to the network infrastructure. This alows security to be implemented without costly changes to each computer. Most important, IPSec allows interoperability among different network devices, PCs and other computing systems.
39.
A.Certificate
B.Encryption
C.Tunnel
D.Presentation
A B C D
B
40.
A.IPSec
B.SSL
C.L2TP
D.The Internet Key Exchange
A B C D
D
41.
A.authenticity
B.IPSec
C.confidentiality
D.integrity
A B C D
B
42.
A.characteristics
B.associated links
C.digital certificates
D.attributes
A B C D
C
43.
A.secure
B.relation
C.script
D.strict
A B C D
A
[解析] 加密(Encryption)用来确保私用网络中两端点的保密性、完整性和认证性。因特网密钥交换(The Internet Key Exchange，IKE)是一个应用层协议，认证IPSec交易中的每个同级。IKE谈判安全政策，确定哪种算法可以用来建立隧道。它也处理用于那次交易的会话密钥的交流。 利用IPSec来确保数据流的网络，能通过使用数字证书(digital certificates)自动认证设备，这种证书验证两个来回发送信息的用户的身份。对在需要在很多设备之间安全连接的大型网络中确保数据安全，IPSec是一个理想的方法。 部署了IPSec的用户能确保其网络基础设施的安全(secure)，而不会影响各台计算机上的应用程序。此套协议用做对网络基础设施的纯软件升级。这既允许实现安全性，又没有花什么钱对每台计算机进行改造。最重要的是，IPSec允许不同的网络设备、PC和其他计算系统之间实现互通。
The metric assigned to each network depends on the type of protocol. Some simple protocol, like RIP, treats each network as equals. The ______ of passing through each network is the same; it is one ______ count. So if a packet passes through 10 network to reach the destination, the total cost is 10 hop counts. Other protocols, such as OSPF, allow the administrator to assign a cost for passing through a network based on the type of service required.A ______ through a network can have different costs (metrics). For example, if maximum ______ is the desired type of service, a satellite link has a lower metric than a fiber-optic line. On the other hand, if minimum ______ is the desired type of service, a fiber-optic line has a lower metric than a satellite line. OSPF allow each router to have several routing table based on the required type of service.
The Border Gateway Protocol (BGP) is an interautonomous system. ______ protocol. The primary function of a BGP speaking system is to exchange network ______ information with other BGP system. This network reachability information includes information on the list of Autonomous System (ASs) that teachability information traverses. BGP-4 provides a new set of mechanisms for supporting ______ interdomain routing. These mechanisms include support for advertising an IP ______ and eliminate the concept of network class within BGP. BGP-4 also introduces mechanisms that allow aggregation of routes, including ______ of AS paths. These changes provide support for the proposed supernettting scheme.
。
。注意，试题要求排列成一个环(圆圈)，这就涉及到对称的问题。例如，如果把1、2、3这3个数排成有顺序的序列，则有6种排列方法。但如果要把这3个数排列成一个圆圈，则只有2种排列方法。
个。
。因此，处理task1的资源利用率
。
。
=0.25小时=0.25×60分钟=15分钟。处理task1的平均等待时间
=12.5分钟=0.208小时。
个；处理task2的资源利用率
。
。
=0.1小时=0.1×60分钟=6分钟。
。
个，②Web服务器每秒平均处理事务数
个，③数据库服务器每秒平均处理事务数
个。
；②web服务器的利用率
；③数据库服务器的利用率
。
，可得该信息系统的平均响应时间
+
×235200≈176709.24元。
，分包费用=
。代入上式，即
。
×100%=44.052%
深色：已答题 浅色：未答题