Network+

Transmission Control Protocol /Internet Protocol:
A nonproprietary, routable network protocol suite that enables computers to communicate over all types of networks. Native protocol of the Internet and required for Internet connectivity.

1. network/node address structure
2. tools for static and dynamic address assignment
3. name resolution services
4. utilities for testing and configuration.

1.0.0.0 to 127.255.255.255
1st octet
last 3 octets
255.0.0.0

128.0.0.0 to 191.255.255.255
1st 2 octets
last 2 octets
255.255.0.0

192.0.0.0 to 223.255.255.255
1st 3 octets
last octet
255.255.255.0

A: 10.0.0.0 to 10.255.255.255
B: 172.16.0.0 to 172.31.255.255
C: 192.168.0.0 to 192.168.255.255

20 (data)
21 (control)

22 (Remote login protocol)

23

25

53

69

80

110

119

123

143

443

File Transfer Protocol

Secure Shell

Simple Mail Transfer Protocol

Domain Name Service

Trivial File Transfer Protocol

Network News Transfer Protocol

Network Time Protocol

Internet Message Access Protocol version 4

Internet Corporation for Assigned Names and Numbers controls the leasing and distribution of IP addresses, formerly handled by IANA (Internet Assigned Number Authority) formed 1993.

Variable length subnet mask:
used to create subnets that each have only the number of nodes required

Classless Inter Domain Routing
also called supernetting;
a subnetting method treating a VLSM as a 32-bit binary word to provide the exact number of nodes and networks required. With CIDR, multiple class-based networks can be represented as a single block. Used for most addressing today.

TCP/IP -> OSI
Application -> App/Pres/Sess
Transport -> Transport
Internet -> Network
Network -> Data/Physical

Utilities such as socket services and NetBIOS over TCP/IP

Connection and communication

Addressing and routing

Services that send and receive frames from the network

IANA

TCP and UDP

Well-known: 0 to 1,023
Registered: 1,024 to 49,151
Dynamic: 49,152 to 65,535

1. TCP: connection-oriented, guaranteed delivery. Sends data, waits for ACK, and fixes errors.
2. UDP (User Datagram Protocol): connectionless, best effort delivery.

Primarily serves to assign correct destination address to a data packet. Resolves name of receiving node to that node's IP address and passes IP address from Transport layer to Internet layer where IP uses the subnet mask to determine if the receiving node is on the same subnet or a remote network, and delivers the packet. (Note: if on a remote network, IP only delivers to the default gateway on the local network, the gateway then undertakes its own MAC resolution process.)

Address Resolution Protocol (in TCP/IP)

Supports the IP by resolving IP address to MAC address.
1. ARP receives IP Addr from IP.
2. If ARP has MAC Addr in cache, it returns it to IP.
3. If not in cache, ARP issues broadcast to resolve IP Addr.
4. The target node responds with a unicast including its MAC Addr.
5. ARP adds MAC Addr to cache and sends it to IP.

Reverse Address Resolution Protocol

Allows a node on a LAN to discover its IP addr from a router's ARP table or cache. A network admin creates a table on the LAN's router that maps each node's MAC addr to an IP addr.

Internet Control Message Protocol
--a service on IP protocol that reports on the condition of a connection between two nodes (to help avoid flooding)

Internet Group Management Protocol
--supports multicasting in a routed environment

A piece of software within an operating system that connects an application with a network protocol. In TCP/IP, the socket links the IP addr with the port number of the service.

{protocol,local-addr,local-process}
Example:
{tcp, 193.44.234.3, 53}

Cyclic Redundancy Check
--uses a predefined math calculation to compute CRC code based on the data block and attaches code to the data block. Receiver uses same calculation to compute and compare CRC code.

Error Detection And Correction
--data sent with an EDC (Error Detection Code); if an error is found, the data can be rebuilt by the receiver.

1. Buffering- temporary storage of input until main system is ready. Typically handled by network card in networking.
2. Data Windows- multiple packets sent as a block or window and acknowledgement sent only for entire block.
2 (a) Fixed windows- set number of packets per block
2 (b) Sliding windows- variable block sizes with size continually reevaluated during transmission

either 4-pin or 6-pin connector for Cat 1 twisted pair cable in phone systems and not suitable for network connectivity.

8-pin twisted pair connector

for 75-ohm coax cable used to connect TV and FM antenna leads. Comes with screw-on or as a slip-on connector.

Straight Tip
Used for multimode fiber optic cable. Have a straight ceramic center bin and bayonet lockdown. Most popular fiber connector and often used in patch panels.

Standard Connector or Subscriber Connector
Used for single-mode fiber optic cable. Box-shaped that snap into a receptacle.

FireWire
Either 6-pin or 4-pin connector.

Local Connector
Used for both single- and multimode fiber optic cable. About half the size of ST or SC with round ceramic ferrule and RJ-45 type latch. Can be used to transition installations from twisted pair copper to fiber.

Mechanical Transfer Registered Jack
Used for multimode fiber optic cable. Compact snap-to-lock connector with TWO strands of fiber attached with one connector.

Twist-lock coax ThinNet connector (RG58/U or RG58A/U cable)

15-pin connector used to connect device to transceiver on ThickNet. Transceiver connected to ThickNet coax with vampire tap which pierces cable.
--Also called DIX connector.

Because this address is in one of the IP address ranges that RFC 1918 recommends be reserved for private networks.

NetBEUI is faster and easier to configure

Repeaters amplify signals on a network, enabling the signal to travel over longer distances and reducing signal degradation. A disadvantage is that on Ethernet networks, there is a maximum amount of time that a signal can take to reach a network, and repeaters slow down travel time.

1) Physical; 2) Data Link; 3) Network; 4) Transport; 5) Session; 6) Presentation; 7) Application -- "Please Do Not Throw Sausage Pizza Away""

Star ring

the physical networking medium, such as cabling, connectors, and repeaters

RJ-11

they generate and detect voltage, to transmit and receive signals carrying data

it sets the data transmission rate and monitors data error rates. It does not provide error correction

it bridges the networking media with the abstract software and data streams

to divide data it receives from the Network Layer into frames that can be transmitted by the Physical layer

Open System Interconnection /1980's

connectivity devices such as bridges and switches, because they decode frames and use the frame information to transmit data to its correct recipient

it manages addressing, routing, and segmentation and reassembly of packets

Number 6 -- It serves as translator between the application and the network. -Data is formatted in a schema that the network can understand; this format varies with the type of network used. -Also manages data encryption and decryption, such as scrambling of passwords.

Number 5 -- Establishes and maintains communication between two nodes on the network. Considered the "Traffic Cop" of network communications.-The term "session" refers to a connection for data exchange between two parties: it is most often used in context of terminal and mainframe communication.

routers belong to the Network Layer because they use addressing, usage patterns, and availability to intelligently direct data from sender to receiver

ensuring data arrives reliably, even across segments. the Transport Layer checks the order or sequence of frames and checks errors

establishing and maintaining communication between two nodes on the network

the Session Layer

a connection for data exchange between two parties; most often with terminal-to-mainframe communications

translates between the application and the network. At the Presentation layer, data are formatted in a schema that the network can understand; this format varies with the type of network used

the Presentation Layer manages encryption and decryption, such as the scrambling of passwords

it provides interfaces to the software that enable it to use network services

IP addresses can be assigned through static addressing (in which IP addresses are permanently assigned to workstations) or dynamic addressing (in which IP addresses are assigned for the current session only. An advantage of static IP addressing is that it doesn’t require a DHCP server. An advantage of dynamic IP addressing is that fewer IP addresses than the total number of workstations can satisfy the needs of a network.

file transfer, file management, and message handling for electronic mail

A router can route data to the correct network in a way that is similar to a switch’s method. However, a router can also forward a message to its correct destination over the most efficient available route to destinations far removed from the LAN it is connected to.

Network Layer addresses and Data Link Layer addresses

Because it is unconcerned about the data that it is routing and is only concerned with the destination address of the data

The Ipconfig (on Windows NT/2000/XP) and Winipcfg (on Windows 9x) commands are used to display a machine’s IP address and the MAC address of its NIC. The Ping command is used to send a signal to a remote computer and test connectivity.

addresses hardwired into the networking device, also called physical, MAC, or hardware addresses

IPX/SPX and TCP/IP are routable, and NetBEUI is not.

addresses assigned to devices through operating software, also called logical or virtual addresses

Regular telephone lines, ISDN, DSL, cable modem, T1, Ethernet

they are hierarchical, so they can be easily interpreted by routers and used to direct data to their destinations

Possible answers: Cable modem and DSL

10-Mbps Ethernet (10 Mbps), Fast Ethernet (100 Mbps), and Gigabit Ethernet (1000 Mbps)

100 meters (328 feet)

two sublayers: the Logical Link Control (LLC) sublayer and the Media Access Control (MAC) sublayer

The transmission speed (100 Mbps)

reliability and flow control services

it appends the physical address of the destination computer onto the data frame

1. ThinNet (185 m max)
a) RG58/U - 5 mm, solid core, 50 ohms
b) RG58A/U - 5mm, stranded core, 50 ohms

2. ThickNet (500 m max)
RG8 - 10 mm, solid core, 50 ohms

UTP (Unshielded Twisted Pair)
- typically 4 pair of stranded or solid conductors. Lengths up to 100 m.

STP (Shielded Twisted Pair)
- typically 4 pair of stranded or solid conductors surrounded by foil. Lengths up to 100 m [same as UTP]. Used in Token Ring networking

1 - Voice, not networking
2 - Digital phone and low-speed networks. Max 4 Mbps
3 - Ethernet. Max 10 Mbps
4 - IBM Token Ring. Max 16 Mbps
5 - Fast Ethernet. Max 100 Mbps
5e- Gigabit Ethernet. Max 350 Mbps
6 - Gigabit Ethernet. Max 1 Gbps
7 - Gigabit Ethernet. Max 1+ Gbps
NOTE: The primary difference between Cat 3 and Cat 5 cable is the number of twists per inch, with Cat 5 more tightly wound.

Carries single optical signal. Small core (down to 5 microns) allows only a single beam of light.

Core typically 50 microns or larger, permitting multiple optical signals. Light sent at angles, reflecting off sides of the strand along the length.

Core typically 50 microns or larger, allowing mutiple beams. Light transmitted through each of multiple layers inside core. Longer maximum distance and more expensive than step index multimode fiber.

FireWire (IEEE 1394) use a shielded cable similar to STP with either 4 or 6 conductors. Can connect up to 63 devices to form a small local network.

A device used to connect the drops in a physical star topology into a logical bus topology. Support speeds of 10 Mbps or 100 Mbps or both simultaneously.

- Active hub also serves as a repeater.
- Managed hub (aka intelligent hub) enable admin to monitor and configure operation.
- Switching hub reads destination of packet and directs it to correct port. May also support load balancing.

Used to connect drops in a physical star topology into a logical bus topology. Forward packets to correct port based on MAC addr. Works with a pair of ports connecting two segments as needed.

- Cut-through: forwards packet as soon as received. No error checking or processing.
- Fragment-free: Examines first 64 bytes of each packet for damage by a collision. Forwards packet only if no damage found, thus reducing network congestion.
- Store-and-forward: Calculates CRC for each packet and forwards only if matched.

Divides a logical bus network into subnets. Examine MAC addr of each packet and forwards only if addressed to a different port (segment). Generally, a bridge should be located so that no more than 20% of traffic needs to cross the bridge.

- Learning bridge: Examines traffic and determine the addresses of the subnets connected to each port, configuring themselves automatically.

Connects multiple networks that use the same protocol. Can only work with routable protocols: those that provide separate network and node addresses. Can be a dedicated device or implemented as software running on a node, typically with two NICs.

Converts data between incompatible systems. May be a device, software or a system. May translate data between different operating systems, between different email formats, or between different networks.

NOTE: Do not confuse a gateway with what TCP/IP calls a default gateway which just forwards IP data packets.

The intermediary between the computer's data bus and the network. aka network adaptor or network card.

Identify the NIC by opening local area connection Properties and viewing the 'Connect Using' area.

Connects wireless devices and can connect to wired networks. Have a network interface to connect to a wired network and an antenna or infrared receiver to receive wireless signals.

The ITU (International Telecommunications Union), which in 1992 absorbed the functions of the CCITT.

Device that both sends and receives data. Today, most are built into the network card. Used to connect NIC to the network media.

This is a role, not a specific device.

A device that regenerates a signal to improve transmission distance. Used frequently with coax media. Most networks now use twisted pair cabling and do not have repeaters.

5-4-3 Rule: Can connect up to 5 segments using 4 repeaters; however, only 3 of those segments can contain nodes.

Bus, Ring, Star, and Mesh

a) Physical bus - Each node is connected directly to a network cable with a T-connector or tap. Data signals pass by the node, not through the node.
b) Logical bus - Network in which all nodes see the network signal at the same time.

the basic physical layout of a network; it does not specify devices, connectivity methods, or addresses on the network

a) Physical Star - uses a central connectivity device, such as a hub, with separate connections to each node.
b) Logical star - Central device polls each node to see if it needs to transmit and controls the amount of access the node has to the cable. Less common than logical ring or logical bus.

Number 1-- contains Physical networking medium:cabling,connectors,repeaters-Protocols generate & detect voltage so as to transmit and recieve signals. -Sets the transmission rate, monitors data,error rates, does not correct errors.

a) Physical ring - All nodes are connected in a continuous circle. Each node reads the signal from its upstream neighbor and retransmits signal to its downstream neighbor. Signal quality is high.
b) Logical ring - Each node receives data only from its upstream neighbor and retransmits only to its downstream neighbor.

"bus, ring, and star

a) Physical mesh - Each node has a direct connection to every other node. Typically used to provide reliable connections between separate independent networks.

Number 3 -- Manages addressing and routing data based on addressing patterns of usage and availability.-Routers belong because they use the information to intelligently direct data from sender to receiver. -Responsible for segmentation and reassembly.

IEEE 802.2

Number 4 -- Responsible primarily for ensuring that data are transferred from point A to B (which may or may not be on the same network segment) reliably and without errors.-Example:Transport layer ensures that data are sent and received in the same order, or sequence. It also establishes the level of packet error checking.

Number 7-- It provides interfaces to the software that enable it to use network services. Some of the services provided by the application layer include file transfer, file management, and message handling for electronic mail.

IEEE 802.3

IEEE 802.11

LLC (Logical Link Control enables multiple upper-layer protocols to share the same media. Controls how frames are placed on the media. Checks CRC and either ACKs or NACKs the data. Controls data flow so the input doesn't flood.
MAC (Media Access Control) manages media access method. [Don't confuse it with MAC address.] In contention-based networks, MAC sub-layer is responsible for the carrier sense; in a token passing network, it is responsible for the token.

Logical Link Control --
Developed to address the need for MAC-layer addressing in bridges. Specifies the frame size and rate. Packets can be sent over Ethernet and Token Ring networks using either copper or fiber media.

Number 2 -- bridges the networking media with astract software and data streams.-Primary function to divide data it receives from network layer into frames that can be transmitted by the physical layer. -Bridges, switches work because they decode frames and use the frame information to transmit data to correct recipient.

a hybrid of more than one simple physical topology

Ethernet uses CSMA/CD and is most efficient in a physical star, logical bus topology --
IEEE Spec/Speed/Type of Ethernet/IEEE Standards --
a) 802.3/ 10Mbps/ Ethernet/ 10Base2/5/FL/T (e.g. 10Base2 & 10Base5 & 10BaseFL etc.)
b) 802.3u/ 100Mbps/ Fast Ethernet/ 100BaseFX/T/T4/TX
c) 802.3z/ 1000Mbps or 1Gbps/ Gigabit Ethernet/ 1000BaseCX/LX/SX/T
d) 802.3ae/ 10Gbps/ 10 Gigabit Ethernet/ 10GBaseSR/LR/ER

a network that uses the physical layout of a star and the token-passing data transmission method

Token Ring --
- Either 4 or 16 Mbps
- Token passing access
- Physical Star topology connecting each node to a MSAU, or MAU, (Multi Station Access Unit).
- STP/UTP listed as Cat 1, 2, or 3 cable
- Baseband signaling

peer-to-peer, star, ring, mesh, tiered

Fiber Distributed Data Interface --
- 100 Mbps
- Token passing access
- Dual fiber ring topology
Second ring is normally for backup but can carry data in certain installations, extending capacity to 200 Mbps. Provides redundant, high capacity networking with fault tolerance.

1) the distance they must cover
2) the higher number of users they serve
3) and heavier traffic they often handle

A family of specs for Wireless LAN technology --
- 11Mbps (802.11b) or 54Mbps (802.11g)
- Star topology
- CSMA/CA access
- specifies spread spectrum radio devices in the 2.4 GHz band.
- Provides for both FHSS and DSSS.
Two modes are specified:
1) Infrastructure mode uses one or more WAPs to connect workstations to a cable backbone.
2) Ad-hoc mode uses a peer-to-peer configuration in which each wireless workstation talks directly to other workstations.

a WAN with single interconnection points for each location

1) organization has only a few sites
2) access to dedicated circuits

Signal type is either Baseband or Broadband. Specification is {speed}{signal type}{media} such as 10BaseTX: {10Mbps}{Baseband}{2-pair UTP Cat 5}.
Media codes include:
2=ThinNet coax; 5=ThickNet coax; T=UTP or STP Cat 3,4, or 5; TX=2-pair UTP Cat 5; T4=4-pair UTP Cat 3,4, or 5; CX=Balanced copper media on coax; F=Fiber optic; FL=Fiber optic link; FB=Fiber optic backbone; LX/SX/LR/SR/ER=other fiber modes.

transmission methods

a set of rules specifying how data are packaged and transmitted over network media

1. Controlled or deterministic methods
a) Multiplexing, either time-division (TDM) or frequency-division (FDM) in which a multiplexer, or mux, contol access by each node and combine signals from multiple nodes.
b) Polling which may used demand priority
c) Token-based
2. Contention-based or competitive access
a) CSMA/CD (Carrier Sense Multiple Access/Collision Detection) in which a node monitors for collision fragments after transmitting. If collision detected, the node repeats transmission until successful.
b) CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) in which a node transmits a jam signal advertising its intent to transmit data.

1. Broadcast - nondirectional using a single frequency.
a) Low-power, max range about 70 meters.
b) High-power, much longer range; more expensive.

2. Spread spectrum signals are sent over more than one frequency for security.
a) FHSS (frequency hopping spread spectrum) uses one frequency at a time, changing channels at set intervals.
b) DSSS (direct sequence spread spectrum) converts signal into multiple digital data signals called chips. The set of chips is sent simultaneously via multiple frequencies. Also includes EDAC (error detection and correction) information which the receiver uses to reconstruct signal if some channels are noisy.

10KHz to 1 GHz

Token Ring, LocalTalk, FDDI, ATM, and the most popular, Ethernet

In baseband, digital signaling is used to send data over a single medium using the entire bandwidth of that medium. Devices cannot send and receive simultaneously. Multiple baseband signals can be sent by using time-division multiplexing.

In broadband, analog signaling transmits data over a portion of the bandwidth of the medium. Devices cannot send and receive over the same broadband channel. Multiple broadband signals can be combined and sent over a single medium by using frequency-division multiplexing.

1. Reliability protocols - provide a way to ensure that data transfer occurs.
2. Connection protocols - Used for establishing a connectionless or connection-oriented service for upper layers.
3. Routing protocols - ensure that data is transferred to the correct location. In an unswitched network, routing is virtually unnecessary because nodes are directly connected. In a switched network, the routing function determines the path of a data packet.

1. Terminal emulation protocols
2. File access and file transfer protocols
3. Email protocols
4. Remote action protocols - determine whether a process should be performed by a client node or a server.
5. Multiple session protocols - enable multiple network links to be established.
6. Network management protocols
7. Task-to-task protocols - enable software processes to communicate over network.
8. Codeset and data structure protocols - Define how data is represented and translate data for nodes tha use different coding schemes.

switching

IPv4 uses a 32-bit address for a max of ~4,295 billion addresses and divides the address space into fixed classes.

IPv6 uses a 128-bit address divided into eight 16-bit blocks. Also provides hierarchical addressing, simplified headers, support for time-sensitive traffic, and a new structure for unicast addressing.

circuit switching, message switching, packet switching

Carrier Sense Multiple Access with Collision Detection (CSMA/CD). Ethernet networks at any speed of any frame type use CSMA/CD

A Channel Service Unit/Data Service Unit is a combination of two WAN connectivity devices that work together to terminate the ends of a digital T1 or T3 line from a phone network. The DSU receives the signal from the LAN and passes it to the CSU which converts the signal to be compatible with the digital data service (DDS) on the WAN line. The DSU and CSU can be separate devices or combined into one device.

collisions increase

Integrated Services Digital Network is a digital switching technology that carries both voice and data over digital phone lines or PSTN wires. The terminal adapter prepares data for transmission on the phone line.

4Mbps, 16Mbps, 100Mbps, and 1Gbps

Software or hardware device that blocks unsolicited traffic.

IEEE 802.5
Very similar to the other Token Ring standard, IBM Token Ring.

Public Switched Telephone Network
Also called POTS (Plain Old Telephone Service)

generally more expensive than Ethernet

1-Physical: Hub, Repeater
2-Data-link: Switch, Bridge
3-Network: Router

NIC and WAP work between layers 1 and 2.

high reliability and fault tolerance

Multistation Access Units (MAUs)

NetBEUI (NetBIOS Extended User Interface) is found in Windows 95 and older networks. Fast and simple. Relies on NetBIOS broadcast traffic for node discovery and name resolution which is inefficient. Implemented at data-link layer of OSI, identifying nodes by both a NetBIOS node name and MAC address. MAC address has no location (network) element so NetBEUI is NOT routable.

IPX/SPX (Internetwork Packet Exchange/Sequenced Packet Exchange) is a proprietary routable network protocol used in older (v. 3 & 4) Novell NetWare. [Now use TCP/IP]
IPX is a connectionless, Network-layer protocol providing best-effort data delivery.
SPX is a connection-oriented Transport-layer protocol providing guaranteed data delivery.

IPX/SPX nodes are assigned a 12-byte IPX internetwork number represented by 24 hexadecimal digits: 4 byte network number / 6 byte node number / 2 byte socket number. A server is assigned both an 8 char name and an 8 digit hexadecimal address (4 bytes).

Class A: N H H H;
Class B: N N H H;
Class C: N N N H

AppleTalk is a routable protocol used in older Mac networks. [Now use TCP/IP]
AppleTalk networks have a hierarchical address structure and supports various physical topologies, including TokenTalk, EtherTalk, and FDDITalk.
Windows servers include support for AppleTalk; however, for Mac clients to authenticate to Windows server computers, the Windows servers must also run the Services for Macintosh network component, providing file and print services for Mac clients.

AppleTalk networks can interoperate with TCP/IP networks. AppleTalk over IP is provided by Apple and other vendors.

Class B

1. Static addresses are manually assigned by admin at each node. Typically used only for dedicated devices such as router interfaces, network printers, or servers.
2. Dynamic assignment is made automatically by a DHCP (Dynamic Host Configuration Protocol) server.
3. Self-assigned using APIPA (Automatic Private Internet Protocol Addressing), a service enabling a DHCP client to configure itself automatically with an IP address in the range of 169.254.0.1 to 169.254.255.254 if no DHCP server responds to the client's DHCP discover broadcast. APIPA addresses are not routable.

Class C

Public IP addresses are available for use on the Internet. Private IP addresses are used on private intranets that are isolated from the Internet. Networks that use private IP addresses can access the Internet through a proxy server, which substitutes its IP address for the address of the device trying to access the Internet.

Packet switching
Circuit switching
ISDN
FDDI
T1
T3
OCx
X.25

Modulation, demodulation

A WAN switching technology in which each packet takes the best route available.

A WAN switching technology in which a single path from one endpoint to another is built when a connection is needed. Once the path is established, all data follows that path. The path is dropped when the connection is no longer needed. The path, and therefore the connection characteristics, may differ each time the connection is made.

Half-duplex, full-duplex

Modem transmission rates are limited by the design of the phone lines as well as the method that phone companies use to convert analog to digital. The overhead of data transmission must also be taken into account. All these factors combine to limit modem transmission over a regular phone line to around 56.6 Kbps. Line noise and available wiring can further limit transmission speed so that 56.6 Kbps cannot be attained.

A WAN technology using digital circuit switching. Uses multiple communication channels with two interface modes: Basic Rate Interface (BRI) or Primary Rate Interface (PRI) which provides more channels for higher bandwidth.

The T-Carrier system is a WAN technology designed to carry multiplexed phone connections.

T1 has speed of 64 Kbps and 24 channels allowing 24 concurrent connections or 1.544 Mbps total bandwidth.

T3 supports 672 channels for 44.736 Mbps total bandwidth (28 T1 lines).

The Optical Carrier (OC) system is a channelized WAN technology for fiber optic cable. The base rate (OC1) is 810 channels for 51.84 Mbps but the standard is open ended. As hardware is developed for faster speeds, new specs are added; e.g., OC3 has 3X the channels and speed of OC1; OC192 has 192X the channels and speed as OC1.

A WAN technology developed in the 1970's using packet switching to get reliable delivery through phone lines.

IP Security is a nonproprietary suite of security standards providing end-to-end authentication and encryption for sessions on IP networks. Allows each client to access resources based on the security level of that particular client.

Layer Two Tunneling Protocol is an internet standard for tunneling PPP sessions across a variety of network protocols, including IP, frame relay, and ATM. L2TP tunnels appear as IP packets, so IPSec Transport Mode provides authenticity, integrity, and confidentiality security controls.

A security protocol combining digital certificates for authentication with RSA public-key data encryption. A website that supports the HTTPS protocol must have an SSL security certificate.

Wired Equivalent Privacy is an older security protocol for wireless networks which has been replaced by WPA. WEP defines an algorithm which gives users the same level of privacy they would have on a wired network not protected by encryption. WEP accounts for lost packets, is self synchronizing, and requires little maintenance.

Wi-Fi Protected Access is a security protocol for wireless networks designed to improve upon WEP. WPA provides improved data encryption and user authentication through the Extensible Authentication Protocol (EAP).

A security protocol for implementing Extensible Authentication Protocol (EAP) over either a wired or wireless Ethernet LAN. Employs an authentication service to secure wireless clients.

Extensible Authentication Protocol enables sytems to use hardware-based identifiers, such as fingerprint scanners or smart card readers, for authentication.

Tunneling is a data transport technique in which a data packet from one protocol ('passenger protocol') is transferred inside the frame or packet of another protocol ('carrier protocol'). This can encapsulate and route nonroutable passenger protocols or provide additional security by hiding passenger data from the carrier network.

A Virtual Private Network provides a secure connection between endpoints by tunneling through a public network. Special VPN protocols are required.

Remote Access Services enable a remote node to connect to a network.

Point-to-Point protocol is the current internet standard for sending IP datagram packets over serial point-to-point links. Can be used in synchronous or asynchronous connections. Supports use of NetBEUI, IP, IPX, and AppleTalk by encapsulating data within the Network Control Protocol (NCP).

Serial Line Internet Protocol is a legacy remote access protocol used for sending IP bytestreams over serial lines such as modem/phone connections. No error checking and no security. Rare today.

Point-to-Point Protocol over Ethernet is a standard providing the functionality of PPP to DSL or cable modem connections that use Ethernet for client connections. It contains a discovery protocol that determines a client's Ethernet MAC address prior to establishing a connection.

Point-to-Point Tunneling Protocol is a Microsoft VPN protocol that increases the security of PPP by providing tunneling and data encryption for PPP packets. Encapsulates any type of network protocol and transports it over IP networks.

Remote Desktop Protocol provides secure remote control of a desktop. Included in Windows Terminal Services. When a client is accessing an application on the Terminal Server, only a screen view is transmitted, not the actual data, which reduces the bandwidth required for the remote session.