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M any companies have multiple locations that need to share network. Costs can vary wildly between different technologies, speeds, and other factors (including your location), so you need to rely heavily on cost and availability data from local providers for your own WAN analysis. N How quickly does the data need to be transferred?. N Does the data transfer need...
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However, given its heavy past use, and the remote chance that you might run into a system using a POTS connection for some type of data transmission, you should be familiar with it.. (Each bearer channel can carry one voice call at a time.) The third channel, called a data channel, carries call setup information and other overhead communications necessary...
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military originally developed and designed X.25 to make military voice traffic available even after a nuclear strike. objective, X.25 is an extremely reliable, secure protocol for transmitting data. All frames (similar to packets) sent over X.25 networks are completely verified from one end of the connection to the other.. In this chapter, you learned about concepts and technologies relating to...
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As you can see, most of the Internet services that you might be familiar with actually work through the use of TCP and/or UDP ports, such as HTTP for the Web, SMTP for e-mail, NNTP for Usenet, and so forth. N Version This field indicates the version of the IP protocol being used.. N Header length This field indicates the...
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Computer IP Address (Dec Computer IP Address (Bin Subnet mask (Dec . Subnet mask (Bin . The netid of an address, defined by the subnet mask, is whatever portion of the address has a binary 1 set in the corresponding subnet mask. In the preceding example, the netid is the full first three octets (the first 24 bits), and the...
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The following are some of the main branches:. If the receiving system knows of the recipient, it acknowledges the request, and then the sending system transmits the body of the message along with any attachments. Each conversation does not use all of the available bandwidth on the line. Add all of this up, and each voice conversation is likely to...
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Exploring Directory Services. Directory services work to bring organization to this far-flung network clutter. In this chapter, you learn about what directory services do and how they work. You also learn about the directory services in use today and those slated for use in the near future. With directory services becoming more and more central to the administration of networks,...
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You should know about five important directory services: Novell eDirectory, Microsoft’s Windows NT domains, Microsoft’s Active Directory, X.500 Directory Access Protocol, and Lightweight Directory Access Protocol. One thing common to all directory services is a tree-based organization (with the tree usually depicted upside-down with the root at the top), somewhat similar to the organization of directories on a hard disk....
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To specify an X.500 address fully, you provide five fields, as in the following:. LDAP’s advocates claim that it provides 90 percent of the power of X.500, but at only 10 percent of the processing cost. (Some other RFCs also describe aspects of LDAP.) The LDAP standard describes not only the layout and fields within an LDAP directory, but also...
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You also need to know about another important type of network connection: remote access to a network. With today’s travel-happy corporate cultures, and with companies needing to support such things as working from home and small remote offices, remote access has become more important than ever. One of the big problems with remote access is that it can seem as...
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Or you can find different solutions that are consistent with the amount of bandwidth you can offer.. You can estimate a particular application program’s bandwidth requirements by actually measuring the amount of bandwidth that application uses. On the LAN, you can monitor the amount of data being sent to a particular node that uses the application in the way it...
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ISDN users, on the other hand, have the choice of either connecting to an ISDN-capable ISP or to ISDN “modems” hosted on the LAN. A VPN connection is carried over a shared or public network—which is almost always the Internet. VPN connections cost much less than dedicated connections, such as the WAN technologies discussed in Chapter 7, because they take...
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shows a typical login screen after browsing to the SSL VPN’s URL. N Through user names and passwords defined in the SSL VPN for each user.. Choosing this option lets remote users use their normal network user name and password, and the SSL VPN then integrates with the preexisting authentication system on the network.. N Access to a remote node...
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Having said that, network security is one of the most important jobs facing any network administrator. Good network security helps prevent the following:. N Company secrets, such as proprietary designs or processes, falling into the wrong hands (both internally and externally). N Loss of use of the network itself or any part of the network N Corruption or inappropriate modification...
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Another type of internal security that you need to maintain for information on your network involves the users’ access to files and directories. These settings are actually a bit tougher to manage than user accounts, because you usually have at least 20 directories and several hundred files for every user on the network. The solution is to establish regular procedures,...
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Another example is to sort through a company’s trash looking for records that might help the culprit crack a password. Make sure to instruct your company’s employees carefully to never give out their password to anyone over the telephone and also that IT people usually never need to ask anyone’s password.. N You’re better off if you can host the...
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Network Disaster Recovery. N etwork servers contain vital resources for a company, in the form of information, knowledge, and invested work product of the company’s employees. If they were suddenly and permanently deprived of these resources, most companies would not be able to continue their business uninterrupted and would face losing millions of dollars, both in the form of lost...
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Disaster Recovery Plans. A disaster recovery plan is a document that explores how a network recovers from a disaster that either imperils its data or stops its functioning. A company’s external financial auditors often require annual disaster recovery plans, because of the data’s importance to the business and the effect that such a network failure would have on a company.....
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You don’t need to work with computers for very long before you observe firsthand the importance of good backups. In cases such as these, jobs are saved or lost based on the quality of the backups in place and the ability to restore that important data.. N How much time is available to make the backup? Make sure that you...
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This lets you restore any of the previous three days’ data. In the standard GFS scheme, where full backups are made all the time, you could restore a file from any given day for a week’s time, for any given end of the week (Friday) for a month’s time, or for any given month for a year’s time. You could...