4.1 Explain the purpose and features of various network appliances.
Load Balancer : A load balancer is used to distribute workload across multiple computers or a computer cluster. It could be done by a dedicated hardware or software.
Proxy server: proxy servers cache website information for the clients, reducing the amount of requests that need to be forwarded to the actual corresponding web server on the Internet. These save time, use bandwidth efficiently also help to secure the client connections.
Content Filter: filtering is used categorize the websites on the internet. You can allow/block specific website access to the web users of the organization. This can be done by referring to central database or by classifying the websites in real time. filtering can also be made applicable only during certain times of a day or days of a week, if required.
VPN concentrators allow for secure encrypted remote access
4.2 Given a scenario, use appropriate hardware tools to troubleshoot connectivity issues.
Shielded cables usually comprise of one or two insulated wires that are surrounded by an aluminum Mylar foil or a woven braided shield. The foiled shield of the cable ensures better signal transmission by eliminating irregular power frequency and external radio interference. Mostly, power cables which carry high-voltage of electricity are shielded for greater protection and better electric transmission. Shielded cables exhibit better interference rejection characteristics compared to unshielded cables.
The IEEE 1394 interface is a serial bus interface standard for high-speed communications frequently used by personal computers, as well as in digital audio, and digital video, The interface is also known by the brand names of FireWire (Apple), i.LINK (Sony), and Lynx (Texas Instruments).
A punch down tool, also called a punch down tool is used widely by network technicians. It is used for inserting wire into insulation-displacement connectors on punch down blocks or patch panels.
A crimping tool is a tool designed to crimp or connect a connector to the end of a cable. For example, network cables and phone cables are created using a crimping tool to connect the RJ-45 and RJ-11 connectors to the end of the cable.
RG-6 may be used for both analog and digital television transmission.
A toner probe is a simple cable continuity tester. It consists of two pieces of equipment. One is the tone generator and the other is the probe. One end of the cable is hooked to the tone generator, and the other end is observed for tone using a matching probe. It is also called "fox and hound" wire tracer.
A protocol analyzer is used to monitor and troubleshoot problems such as suspicious activity on the network, verification of network load and type of traffic, artificially injecting load on to a network for the purpose of load testing, and other hard to detect problems with the network.
Certifier, or a certification tester is used to examine whether the network complies with ISO or TIA standards as applicable. Some certifiers will also have the capability to test the email, DNS, and DHCP servers for proper response times.
TDR, Time Domain Reflectometer is a tool that finds faults in metallic cabbles like twisted wire pairs and coaxial cables. A similar device, OTDR (short for Optical Time-Domain Replectometer) is used for testing fiber optic cables.
4.3 Given a scenario, use appropriate software tools to troubleshoot connectivity issues.
PING Used to ping the remote system (or the local host) to see that the TCP/IP connection is through.
NBTSTAT This utility displays current NetBIOS over TCP/IP connections, and display NetBIOS name cache.
NETSTAT Displays protocol statistics and current TCP/IP connections since the server was last booted. The command netstat provides active connections on the host with detail like local address, foreign address, etc.
TRACERT Used to determine which route a packet takes to reach its destination from source.
IPCONFIG Used to display Windows IP configuration information. The command ipconfig can be used to display the current TCP/IP configuration of a Windows 2000 computer. Note that on a Win9x, we use winipconfig command to view the current TCP/IP configuration.
NSLOOKUP This utility enables users to interact with a DNS server and display resource records.
ROUTE Used to display and edit static routing tables.
ARP: It is used to view the logical and physical address mapping. (Short for Address Resolution Protocol) cache entries are added to an arp cache table either as static entries (manually entered) or as dynamic (system learned) entries. The cache entries help in minimizing the network load, since it is not necessary to resolve an IP address to hardware address every time a packet is received.
"Fixed arp cache entry" and "Temporary arp cache entry" are fictitious anwers.
RARP (Reverse Address Resolution Protocol): RARP is used to obtain IP address from a known MAC address.
BootP (Bootstrap Protocol): When a diskless workstation is powered on, it broadcasts a BootP request on the network. A BootP server responds with its IP address, Default gateway, etc.
Protocol Analyzer And Packet Analyzer (Sniffer): These are loaded on a computer and are controlled by the user in a GUI environment; they capture packets enabling the user to analyze them and view their contents. Example Network Monitor
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