Diagnostic Tools

Diagnostic Tools• Network Monitor - Tracks usage of network resources(good for establishing a network baseline).
• Performance Monitor - Tracks usage of various resources over time(good for establishing a general baseline).
• Tone Generator - Used to test cabling. Identifies which cable or wire is being tested by generating different tones.
• TDR (Time Domain Reflectometer): Sends a signal down a cable and measures the distance that the signal travelled before bouncing back(like sonar). Used to find opens and shorts in cables.
• Oscilloscope - Tests cable by determining where there are shorts, crimps or attenuation.
• Protocol Analyzers - This tool is used to monitor network traffic and display packet and protocol statistics and information.
• Optical Testers - A tool used to monitor and troubleshoot the performance of a fiber optic network.
• Crimping Tools - Crimping tools are used to connect cabling to their appropriate connectors. There are different crimping tools for different types of connections.
• Punch Down Tool - A punch down tool is used to connect cabling such as telephone and ethernet to wall jacks.

Network Management

Network Management
This section discusses network management, storage and recovery concepts:
• VLAN - A virtual LAN is a local area network with a definition that maps workstations on some other basis than geographic location (for example, by department, type of user, or primary application). The virtual LAN controller can change or add workstations and manage loadbalancing and bandwidth allocation more easily than with a physical picture of the LAN. Network management software keeps track of relating the virtual picture of the local area network with the actual physical picture.
• Fault Tolerance - Fault-tolerance describes a computer system or component designed so that, in the event that a component fails, a backup component or procedure can immediately take its place with no loss of service. Fault tolerance can be provided with software, or embedded in hardware, or provided by some combination. This is an important component of disaster recovery which is being included more and more in operating system software. For example, Windows 2000 includes RAID and tape backup functions although additional hardware is required.
• Network Attached Storage - Network Attached Storage, or NAS, is a data storage mechanism that uses special devices connected directly to the network media. These devices are assigned an IP address and can then be accessed by clients via a server that acts as a gateway to the data, or in some cases allows the device to be accessed directly by the clients without an intermediary. Some of the big advantages of NAS include the expandability; need more storage space, add another NAS device and expand the available storage. NAS also brings an extra level of fault tolerance to the network. In a direct attached storage environment, a server going down means that the data that that server holds is no longer available. With NAS, the data is still available on the network and accessible by clients. Fault tolerant measures such as RAID can be used to make sure that the NAS device does not become a point of failure.

Remote Access Protocols and Services

Remote Access Protocols and ServicesThis section describes some of the various protocols and services used for remote and secure connections.
• RAS - RAS stands for "Remote Access Service", Microsoft's term for modem pools. This service provides dial-in access to networks and to the Internet.
• PPP - Point-to-point Protocol (PPP) is a method for connecting a personal computer to the Internet using a standard phone line and a modem. The difference between PPP and other, older dial-up procedures is that a PPP setup will establish a direct Internet connection that allows the PC to use TCP/IP (Internet-based) applications.
• PPTP - The Point to Point Tunneling Protocol (PPTP) provides for the secure transfer of data from a remote client to a private server by creating a multi-protocol Virtual Private Network(VPN) by encapsulating PPP packets into IP datagrams. Setting Up PPTP requires a PPTP Client, PPTP Server and a Network Access Server(NAS). PPTP does not support the Appletalk protocol.
• IPsec - IPSec is a suite of Internet-standard protocols that allow secure, encrypted communications between two computers over an insecure network. IPSec provides end-to-end security, meaning that the IP packets are encrypted by the sending computer, are unreadable en route, and can be decrypted only by the recipient computer.
• L2TP - L2TP creates a tunnel through a public network that is authenticated on both ends, uses header compression, and relies on IPSec for encryption of data passed through the tunnel. L2TP works like PPTP in that it creates a "tunnel", but uses IPSec encryption in order to support non-IP protocols and authentication.
• SSL - SSL (Secure Sockets Layer) uses a technique called public-key cryptography to provide encrypted connections. This enables you to move information across the Internet with confidence that it will not be intercepted or modified in transit. This is heavily used in e-commerce and can be identified by a URL that begins with HTTPS.
• Kerberos - This form of security has been evolving in the Unix world for a long time and is now becoming a standard. Kerberos provides mutual authentication between a client and a server or between servers before a network connection is opened between them. Rather than sharing a password, computers share a cryptographic key, and they use knowledge of this key to verify each other's identities. Kerberos security only works with computers running Kerberos security software.

CCNA NOTES

• FDDI - Fiber Distributed Data Interface (FDDI) is an appealing choice for high-speed data networking. Essentially, it is a very high-speed token ring network connected by optical fibers. With a data transfer rate of 100Mbps, the ring can support up to 500 nodes with as much as 2 km of spacing between adjacent nodes.
• ATM - ATM stands for Asynchronous Transfer Mode and is a high-speed, packet-switching technique that uses short fixed length packets called cells. ATM can transmit voice, video, and data over a variable-speed LAN and WAN connections at speeds ranging from 1.544Mbps to as high as 622Mbps. ATM is capable of supporting a wide range of traffic types such as voice, video, image and data.
• Frame Relay - Frame relay is a secure, private network that utilizes a logical path or ?virtual circuit? to allocate bandwidth for high performance transmissions. Frame relay is the premier high-speed packet-switching protocol communicating data, imaging, and voice between multiple locations. Frame relay is available in a range of bandwidths from 56 Kbps to full T1 (1.54 Mbps).