When the system upon which a transport entity is running fails and subsequently restarts,the(21) 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 problem.The still active side of a half-open connections can close the connection using a(22)timer. This timer measures the time the transport machine will continue to await an (23) of a transmitted segment after the segment has been retransmitted the maximum number of times.When the timer (24),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 restarts, half-open connections can be terminated more quickly by the use of the RST segment, the failed side returns an RST i to every segment i that it receives. When the RST i reaches the other side, it must be checked for validity based on the (25) 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.空白处（22）应选择（）

A、give-up

B、abandon

C、quit

D、connection

Astute service providers realize that the continued support of legacy X.25 and asynchronous network element using separate operations network is cost(16).For example,the maintenance of multiple networks can require additional staff. Often, this staff must be trained on multiple vendor technologies, sometimes requiring parallel groups specializing in each (17) .Hence, additional maintenance procedures must be maintained and administrative records are (18) .The duplication of transport facilities to carry (19)network traffic is an inefficient use of resources. And not surprisingly, more technologies installed in a central office means the necessity for more physical space, and an increase in power connections and power consumption migration of these (20) network elements to IP-based DCns is alogical strategy.空白处（16）应选择（）

A、prohibitive

B、feasible

C、connective

D、special

With hundreds of millions of electronic (11)taking place daily, businesses and organizations have a strong incentive to protect the. (12) of the data exchanged in this manner, and to positively ensure the (13) of those involved in the transactions. This has led to an industry-wide quest for better, more secure methods for controlling IT operations,and for deploying strong security mechanisms deeply and broadly throughout networked infrastructures and client devices. One of the more successful concepts to engage the imaginations of the security community has been the development of standards-based security(14) that can be incorporated in the hardware design of client computers. The principle of encapsulating core security capabilities in (15) and integrating security provisions at the deepest levels of the machine operation has significant benefits for both users and those responsible for securing IT operations.空白处（14）应选择（）

A、appliances

B、chips

C、tools

D、means

With hundreds of millions of electronic (11)taking place daily, businesses and organizations have a strong incentive to protect the. (12) of the data exchanged in this manner, and to positively ensure the (13) of those involved in the transactions. This has led to an industry-wide quest for better, more secure methods for controlling IT operations,and for deploying strong security mechanisms deeply and broadly throughout networked infrastructures and client devices. One of the more successful concepts to engage the imaginations of the security community has been the development of standards-based security(14) that can be incorporated in the hardware design of client computers. The principle of encapsulating core security capabilities in (15) and integrating security provisions at the deepest levels of the machine operation has significant benefits for both users and those responsible for securing IT operations.空白处（15）应选择（）

A、software

B、form

C、computer

D、silicon

对等式局域网中的各台计算机既是网络服务的（）——服务器，又是网络服务的（）——工作站。

局域网操作系统让网络上的所有连接站点地位平等，这结构称为（）。

A、非对等结构

B、对等结构

C、并行结构

D、平行结构