* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Document
Policies promoting wireless broadband in the United States wikipedia , lookup
Airborne Networking wikipedia , lookup
Computer security wikipedia , lookup
Wake-on-LAN wikipedia , lookup
Distributed firewall wikipedia , lookup
Extensible Authentication Protocol wikipedia , lookup
Point-to-Point Protocol over Ethernet wikipedia , lookup
List of wireless community networks by region wikipedia , lookup
Computer network wikipedia , lookup
Zero-configuration networking wikipedia , lookup
IEEE 802.11 wikipedia , lookup
Wireless security wikipedia , lookup
Deep packet inspection wikipedia , lookup
Cracking of wireless networks wikipedia , lookup
Piggybacking (Internet access) wikipedia , lookup
Recursive InterNetwork Architecture (RINA) wikipedia , lookup
UniPro protocol stack wikipedia , lookup
Course ILT Introducing Protocols Unit objectives Discuss access protocols Discuss transport protocols Discuss remote access protocols Discuss security protocols Course ILT Topic A Topic A: Introduction to protocols Topic B: Channel access methods Topic C: Transport protocols Topic D: Remote access protocols Course ILT IEEE 802 series The 802 series of specifications was named after the date when the IEEE Computer Society “Local Network Standards Committee,” Project 802, held their first meeting, which was in February (2) of 1980(80) The 802 series of specifications define the physical media for each specification (802.3, 802.4, 802.5, and so on) Course ILT Protocol compatibility A computer, by using one protocol, cannot communicate directly with a computer that uses a different protocol Course ILT Access protocols The Data Link layer specifies how devices attached to the network can gain access to network resources The Institute of Electrical and Electronic Engineers (IEEE) modified the OSI reference model by breaking the data link layer into two additional layers – Media Access Control (MAC) layer – Logical Link Control (LLC) layer Course ILT The Data Link layer - Modified Course ILT Activity A-1 Identifying protocols Course ILT Topic B Topic A: Introduction to protocols Topic B: Channel access methods Topic C: Transport protocols Topic D: Remote access protocols Topic E: Security protocols Course ILT Channel access methods Determine the physical methodology by which data is sent across the transmitting media Course ILT Introducing Ethernet CSMA/CD networks are more popularly known as Ethernet networks Ethernet and 802.3 are CSMA/CD specifications CSMA/CA The most common implementation of contention access – Does not detect collisions as much as it attempts to avoid collisions (??) Course ILT Data collisions Ethernet topologies Course ILT Some Ethernet topologies (pg 4-9) – – – – – – – – – – – 10Base-T 10Base-FL 100Base-TX 100Base-FX 1000Base-TX 1000Base-CX 1000Base-SX 1000Base-LX 10Base-SR 10Base-LR 10Base-ER Course ILT Activity B-1 Discussing Ethernet methods Course ILT Introducing token passing/Token Ring A token is passed among the nodes of the network Whichever node is in possession of the token is permitted to transmit Token Ring and 802.5 Course ILT Features of Token Ring include – Logical ring usually wired as a physical star – Transfer rate of 4 to 16 Mbps – Unshielded twisted pair, shielded twisted pair, or fiber optic cable – Deterministic, it is possible to predict the passage of the token Course ILT Beaconing The beacon frame is used to define a failure domain The failure domain includes the station reporting the failure, its nearest active upstream neighbor (NAUN), and everything in between Course ILT Failure domain Course ILT FDDI Uses a double fiber ring The secondary ring is for redundancy Runs at 100 Mbps It is typically found as the backbone connecting buildings on a campus or wider area, as nodes can be over 60 miles apart Course ILT ATM Topology that can reach throughput of almost 10000 Mbps – (WAN) Is more commonly implemented at 155 or 622 Mbps Uses small packets, which are called cells Equipment is expensive Smaller organizations will probably go to the cheaper Gigabit Ethernet standard Course ILT Activity B-2 Discussing Token Ring methods Course ILT Wireless – 802.11 and 802.11x IEEE 802.11 is a group of specifications for wireless networks Among others, specifications include 802.11, 802.11a, 802.11b and 802.11g Course ILT Wireless 802.11x wireless networks consist of Wireless Access Points (WAPs) and wireless clients WAPs operate at the Physical and Media Access Control (MAC) layer of the OSI model WAPs can, on average, communicate with up to 30 clients within a 100 meter radius Course ILT Frequency Hopping Spread Spectrum Frequency Hopping Spread Spectrum (FHSS) uses a wide range of frequencies in the 2.4 Ghz band Data is transmitted on a single frequency at any given time, however, the signal hops from frequency to frequency in a pseudorandom pattern This transmission technology can be used by 802.11 Course ILT Direct Sequence Spread Spectrum Direct Sequence Spread Spectrum (DSSS) also operates in the 2.4 Ghz band It employs a mechanism whereby the data being transmitted is spread over multiple frequencies, allowing for higher throughput rates DSSS is used by the 802.11b and 802.11g standards Course ILT Orthogonal frequency division multiplexing With Orthogonal Frequency Division Multiplexing, the radio signal is split into multiple, smaller signals These signals are transmitted at the same time, but at different frequencies OFDM operates in the 5 Ghz band, which makes it more resistant to interference than FHSS and DSSS OFDM is used by the 802.11a standard Course ILT Bluetooth Bluetooth’s aim is to allow the creation of small, short range, wireless networks, usually within a single room It has a range of 10 meters, speeds of up to 1 Mbps and uses FHSS Bluetooth and 802.11x devices cannot communicate with one another Course ILT Infrared Infrared (IR)allows for wireless connection of devices at very close range It is line of sight technology Infrared’s range is up to 1 meter and speeds range from 115 Kbps to 4 Mbps Course ILT Activity B-3 Discussing wireless communications Course ILT Topic C Topic A: Introduction to protocols Topic B: Channel access methods Topic C: Transport protocols Topic D: Remote access protocols Topic E: Security protocols Course ILT Connectionless protocols Used when sending small packets of data, usually less than 1 KB Packets are infrequently dropped No need for the increased overhead of acknowledging each receipt Course ILT Connection-oriented protocols Used to send a large amount of information that is divided into multiple packets for transmission Uses packet sequence numbers to verify packet order and acknowledges the receipt of each packet The lost or improperly delivered packets, which are not acknowledged as a successful receipt, can be retransmitted Course ILT Transport protocols Transport protocols manage network communications and determine how data should be presented to the next layer The protocols responsible for transporting data – – – – NetBEUI IPX/SPX TCP/IP AppleTalk Course ILT NetBEUI NetBEUI (NetBIOS Extended User Interface) is a high-speed protocol first introduced by IBM – Designed for use on small networks (20-200 nodes – Provides good error protection – Provides tuning parameters to match network and organizational requirements continued Course ILT NetBEUI – Has limited memory overhead requirements – Supports both connectionless and connection-oriented traffic – Is not a routable protocol and so does not perform well on larger networks Course ILT NetBIOS NetBIOS (Network Basic Input/Output System) is an application interface operating at the session layer By using NetBIOS – Applications can communicate with NetBIOS-compliant protocols – You can manage communication sessions between computers – You can track computers by the computer name continued NetBIOS Course ILT NetBIOS is supported over NetBEUI – It can be supported over other protocols, such as IPX/SPX and TCP/IP Course ILT IPX/SPX Internetwork Packet Exchange (IPX) Sequenced Packet Exchange (SPX) Course ILT IPX/SPX Is a Novell proprietary protocol Available as monolithic (old) or ODI-compliant IPX provides connectionless service SPX provides connection-oriented services Is a routable protocol Is the default NetWare 3.x and 4.x protocol and supported by NetWare 5.x and 6.x Course ILT TCP/IP The protocol for most medium to largesized networks Is the current de facto standard for internetwork communications Provides guaranteed delivery, proper sequencing, and data integrity checks If errors occur during transmission, TCP is responsible for retransmitting the data Course ILT TCP/IP Transport layer protocols TCP/IP Transport layer protocols User Datagram Protocol (UDP) Course ILT AppleTalk AppleTalk is a protocol suite developed by Apple Corp. in the 1980’s for networks consisting of Macintosh computers The original cabling system used in these networks is called LocalTalk AppleTalk Phase 2 complies with the IEEE 802 standard and provides Ethernet support through EtherTalk Course ILT AppleTalk network addresses AppleTalk network addresses are 24 bits in length 16 bits are used for the network portion and 8 bits for the node’s address The node address is self-assigned Given this setup, there can be 65,000 networks with up to 256 nodes each Course ILT Gateway Connect incompatible networks at the fourth through seventh layers of the OSI model by using protocol conversion and routing services Course ILT Activity C-1 Discussing transport protocols Course ILT Topic D Topic A: Introduction to protocols Topic B: Channel access methods Topic C: Transport protocols Topic D: Remote access protocols Topic E: Security protocols Course ILT Remote access protocols Protocols provide a serial connection to a network device, such as a host and a router The standard protocols include – Serial Line Internet Protocol (SLIP) – Point-to-Point Protocol (PPP) – Point-to-Point Tunneling Protocol (PPTP) Course ILT Serial Line Internet Protocol (SLIP) SLIP defines a sequence of characters that frame IP packets over a serial line The protocol was devised to handle communications over fairly slow links (<19.2 Kbps) Serial Line Internet Protocol (SLIP) Course ILT Disadvantages include – Inability to provide packet addressing – Inability to provide any packet ID information – Lack of error detection or error correction mechanisms – Lack of compression mechanisms Course ILT Point-to-Point Protocol (PPP) Is the current methodology for transporting multiprotocol datagrams over point-to-point links Defined to be a multiprotocol transport over serial links and therefore, can support TCP/IP, IPX, DECNet, CLNP, AppleTalk, and other protocol datagrams Point-to-Point Protocol (PPP) Course ILT Advantages include – Ability to employ data compression techniques – Link quality monitoring – Ability to support security features such as confirming the identity of users attempting to establish a connection – Mechanisms for error detection and error correction – Ability to provide a higher level of security through encryption Course ILT Point-to-Point Tunneling Protocol Remote clients can access the corporate network across the Internet securely You can configure PPTP filtering on a network adapter so that only PPTP packets are permitted Operates across PPP connections Data is encrypted and encapsulated inside PPP packets Course ILT Point-to-Point Protocol over Ethernet Point-to-Point Protocol over Ethernet (PPPoE) is derived from the PPP protocol Was designed to provide secure connectivity to the Internet for broadband connections that use an Ethernet rather than a serial connection PPPoE is defined in RFC 2516 Course ILT Remote Desktop Protocol Remote Desktop Protocol (RDP) is part of Windows NT Terminal Server and Windows 2000/2003 Terminal Services RDP enables display of and input into applications running on a remote Windows computer RDP operates at the Application layer of the OSI model Course ILT Activity D-1 Discussing remote access protocols Course ILT Topic E Topic A: Introduction to protocols Topic B: Channel access methods Topic C: Transport protocols Topic D: Remote access protocols Topic E: Security protocols Course ILT Internet Protocol Security Internet Protocol Security (IPSec) is a suite of protocols It’s used to encrypt data packets It uses one of two modes of encryption, transport or tunnel Transport mode is less secure than tunnel mode Course ILT Layer 2 Tunneling Protocol Layer 2 Tunneling Protocol (L2TP) is an extension to the PPP protocol It’s an enhanced tunneling protocol used in VPN implementations Supports multiple protocols Is optimized to work with IPv6 and IPSec Operates at the Data Link layer of the OSI model Is defined in RFC 2661 Course ILT Secure Sockets Layer Secure Sockets Layer (SSL) was developed by Netscape Enables secure, reliable transmissions over the Internet Is supported by both Internet Explorer and Netscape Navigator Uses a private and public key system (RSA) to encrypt and decrypt data transmissions Course ILT Wired Equivalent Privacy Wired Equivalent Privacy (WEP) is a security protocol for secure data transmission in wireless LANs (WLANs) It was intended to simulate the physical security of a wired LAN Uses a single, manually configured, static key for data encryption WEP is not as secure as originally believed Course ILT Wi-Fi Protected Access Wi-Fi Protected Access (WPA) was developed to improve on WEP’s functionality Provides for user authentication using the Extensible Authentication Protocol (EAP) Data encryption is more secure through the use of the Temporal Key Integrity Protocol (TKIP) Course ILT 802.1x 801.1x is a standard that uses EAP for user authentication in 802.11 wireless networks A supplicant (client) requests access to the wireless network from an authenticator (access point) Course ILT Activity E-1 Discussing security protocols Course ILT Unit summary Learned about access protocols Discussed channel access methods Learned about transport protocols Discussed remote access protocols Learned about security protocols