The document discusses the evolution of Ethernet standards over four generations from its creation in 1976. It describes the IEEE 802 project which established standards for LAN communication. The original Ethernet standard defined the data link layer to consist of logical link control (LLC) and media access control (MAC) sublayers. It also established physical layer standards and frame formats for early Ethernet implementations using thick and thin coaxial cable and twisted pair wiring in bus and star topologies. Later changes like bridging and switching increased bandwidth and separated collision domains to support higher data rates.
This document provides an overview of Internet Protocol version 4 (IPv4) and version 6 (IPv6). It discusses the need for a network layer in an internetwork, the key components and functioning of IPv4 including packet structure, fragmentation, and checksum calculation. It then covers the advantages of IPv6 over IPv4 and the differences in packet format and extension headers between the two protocols. Finally, it discusses the challenges of transitioning from IPv4 to IPv6 and different transition strategies like running both protocols simultaneously, tunneling, and header translation.
The document discusses network models including the OSI model and TCP/IP protocol suite. The OSI model has 7 layers - physical, data link, network, transport, session, presentation, and application layers. Each layer has a specific function in communication. Similarly, the TCP/IP protocol suite has 5 layers that correspond to the OSI layers - physical, data link, network, transport, and application. The document also discusses different types of addresses used in networking including physical, logical, port, and specific addresses.
The document discusses the Internet Control Message Protocol (ICMP). ICMP provides error reporting, congestion reporting, and first-hop router redirection. It uses IP to carry its data end-to-end and is considered an integral part of IP. ICMP messages are encapsulated in IP datagrams and are used to report errors in IP datagrams, though some errors may still result in datagrams being dropped without a report. ICMP defines various message types including error messages like destination unreachable and informational messages like echo request and reply.
The document summarizes key concepts related to network layer addressing, error reporting, and multicasting from Chapter 21. It includes:
1) Address mapping allows mapping between logical and physical addresses either statically or dynamically using protocols like ARP.
2) ICMP handles error reporting and network queries that IP lacks. It includes error messages and query messages.
3) IGMP manages group membership and multicast addressing and routing. It allows hosts to join multicast groups.
A MAC address is a 48-bit hardware address that uniquely identifies network interfaces for communication in an Ethernet network. It is stored in the network card's firmware and is usually written as 12 hexadecimal digits separated by hyphens. An IP address is a 32-bit logical address that identifies a device on an IP network and can be configured manually or automatically via DHCP. Private IP address ranges like 10.0.0.0/8 and 192.168.0.0/16 are non-routable and used for local area networks.
The document discusses address resolution protocol (ARP) which maps logical IP addresses to physical MAC addresses on a local area network. It explains that ARP broadcasts a request to find the MAC address associated with a given IP address, and the device with that IP address responds with its MAC. This dynamic address mapping is stored in an ARP cache for future use. It also describes how different network protocols may use ARP or similar methods to perform address mapping between logical and physical addresses.
The document discusses IEEE standards for local area networks (LANs) including Ethernet LANs, Token Ring LANs, and wireless LANs. It describes the IEEE 802 standards family, common LAN topologies and cabling, how CSMA/CD and token protocols work, and comparisons of Ethernet and Token Ring technologies. It also outlines wireless LAN specifications including 802.11, 802.11a, 802.11b, and 802.11g.
This document provides an overview of Internet Protocol version 4 (IPv4) and version 6 (IPv6). It discusses the need for a network layer in an internetwork, the key components and functioning of IPv4 including packet structure, fragmentation, and checksum calculation. It then covers the advantages of IPv6 over IPv4 and the differences in packet format and extension headers between the two protocols. Finally, it discusses the challenges of transitioning from IPv4 to IPv6 and different transition strategies like running both protocols simultaneously, tunneling, and header translation.
The document discusses network models including the OSI model and TCP/IP protocol suite. The OSI model has 7 layers - physical, data link, network, transport, session, presentation, and application layers. Each layer has a specific function in communication. Similarly, the TCP/IP protocol suite has 5 layers that correspond to the OSI layers - physical, data link, network, transport, and application. The document also discusses different types of addresses used in networking including physical, logical, port, and specific addresses.
The document discusses the Internet Control Message Protocol (ICMP). ICMP provides error reporting, congestion reporting, and first-hop router redirection. It uses IP to carry its data end-to-end and is considered an integral part of IP. ICMP messages are encapsulated in IP datagrams and are used to report errors in IP datagrams, though some errors may still result in datagrams being dropped without a report. ICMP defines various message types including error messages like destination unreachable and informational messages like echo request and reply.
The document summarizes key concepts related to network layer addressing, error reporting, and multicasting from Chapter 21. It includes:
1) Address mapping allows mapping between logical and physical addresses either statically or dynamically using protocols like ARP.
2) ICMP handles error reporting and network queries that IP lacks. It includes error messages and query messages.
3) IGMP manages group membership and multicast addressing and routing. It allows hosts to join multicast groups.
A MAC address is a 48-bit hardware address that uniquely identifies network interfaces for communication in an Ethernet network. It is stored in the network card's firmware and is usually written as 12 hexadecimal digits separated by hyphens. An IP address is a 32-bit logical address that identifies a device on an IP network and can be configured manually or automatically via DHCP. Private IP address ranges like 10.0.0.0/8 and 192.168.0.0/16 are non-routable and used for local area networks.
The document discusses address resolution protocol (ARP) which maps logical IP addresses to physical MAC addresses on a local area network. It explains that ARP broadcasts a request to find the MAC address associated with a given IP address, and the device with that IP address responds with its MAC. This dynamic address mapping is stored in an ARP cache for future use. It also describes how different network protocols may use ARP or similar methods to perform address mapping between logical and physical addresses.
The document discusses IEEE standards for local area networks (LANs) including Ethernet LANs, Token Ring LANs, and wireless LANs. It describes the IEEE 802 standards family, common LAN topologies and cabling, how CSMA/CD and token protocols work, and comparisons of Ethernet and Token Ring technologies. It also outlines wireless LAN specifications including 802.11, 802.11a, 802.11b, and 802.11g.
The document describes the Internet Protocol version 4 (IPv4). It discusses the IPv4 datagram format including the header fields, fragmentation, and options. It also covers how IPv4 provides an unreliable datagram delivery service and must be paired with TCP for reliability. The document discusses security issues with IPv4 like packet sniffing, modification, and spoofing, and how IPSec can provide protection against these attacks.
This document discusses the data link layer, which prepares network layer packets for transmission by encapsulating them into frames. It identifies common data link layer protocols for both LANs and WANs. The data link layer controls media access through logical link control and media access control sublayers. Media access control methods include controlled access like token ring and contention-based access like CSMA/CD. Frame structure is also discussed, with frames containing source/destination addresses, error checking fields, and encapsulated network layer data. Different frame types are used depending on the logical and physical network topology.
This document discusses different types of computer network switching, including circuit switching, packet switching, and virtual circuit switching. Circuit switching establishes a dedicated connection between nodes for the duration of a call. Packet switching divides messages into packets that are routed independently through a network on a first-come, first-served basis without dedicated connections. Virtual circuit switching combines aspects of circuit switching and packet switching by establishing paths for packets through a three-phase process of setup, data transfer using local addressing, and teardown.
ICMP is a helper protocol that supports IP by providing error reporting and simple queries. ICMP messages are encapsulated as IP datagrams with a 4 byte header containing the type, code, and checksum. Common ICMP error messages include Destination Unreachable (sent when a datagram cannot be forwarded), Redirect (informs about a better route), and Time Exceeded (sent when the TTL reaches zero).
Ethernet is a family of networking technologies commonly used in LANs, MANs and WANs. It was first standardized in 1983 at 10 Mbps and has since been updated to support higher speeds up to 10 Gbps. Fast Ethernet runs at 100 Mbps using the same frame format as standard Ethernet. Gigabit Ethernet runs at 1 Gbps while maintaining compatibility. Ten-Gigabit Ethernet operates at 10 Gbps while keeping the same frame format as prior standards.
A switched network consists of interconnected nodes called switches that can temporarily connect devices linked to the switch. There are three main types of switching: circuit switching, datagram/packet switching, and virtual circuit switching. Circuit switching requires resource reservation and dedicates resources for the duration of a connection. Datagram switching does not reserve resources and allocates them on demand. Virtual circuit switching has aspects of both by dedicating resources only for packets belonging to the same connection. Switches can be constructed in single-stage or multistage designs, with multistage switches using fewer crosspoints.
- IPv4 addresses are 32-bit numbers that uniquely identify devices connected to the internet. IPv6 addresses are 128-bit numbers introduced to replace IPv4 due to its limited 32-bit address space running out.
- IPv4 addresses are divided into classes A, B, C based on the first bits, with each class allocating a different number of addresses. IPv6 addresses use a 128-bit address space and are written in hexadecimal colon notation.
- Network Address Translation (NAT) was introduced to allow sharing of IPv4 addresses since the available addresses were insufficient. NAT maps private IPv4 addresses to public addresses for connecting to the internet.
The document discusses various IEEE 802 standards for networking technologies including Ethernet, wireless LAN (802.11), and their variants and evolutions over time. It provides details on Ethernet standards and implementations such as 802.3, 10BASE5, 10BASE2, 10BASE-T, 10BASE-F, Fast Ethernet, and Gigabit Ethernet. It also summarizes key aspects of wireless networking standards such as 802.11 components, frame format, and physical layer specifications including FHSS, DSSS, OFDM, and associated data rates and frequencies.
Controlled access protocols allow only one node to send at a time to avoid message collisions. There are three main controlled access methods: reservation, polling, and token passing. Reservation methods divide time into intervals, with reservation frames preceding data frames to reserve slots. Polling methods involve a primary station periodically polling secondary stations for data. Token passing methods use a token frame that circulates between stations, with each station only allowed to transmit when holding the token.
Distance vector routing works by having each node maintain a routing table with the minimum distance to reach every other node. Nodes share their routing tables with immediate neighbors periodically or when changes occur, allowing each node to learn optimal routes throughout the network. Each node sends only the minimum distance and next hop information to neighbors, who update their own tables. This sharing of routing information allows all nodes to gradually learn the least-cost routes.
The document discusses various technologies used for data transmission over telephone and cable networks, including:
1. Telephone networks originally used analog circuit switching to transmit voice calls but have transitioned to separate digital data transfer and signaling networks.
2. Traditional telephone lines support dial-up modems using modulation/demodulation to transmit data within the 3000Hz bandwidth for voice calls.
3. Digital Subscriber Line (DSL) technologies like ADSL provide higher bandwidth internet over existing telephone lines by using frequencies up to 1.1MHz.
4. Cable networks originally provided unidirectional video but now support bidirectional high-speed internet using technologies like DOCSIS to share bandwidth over coaxial and fiber-opt
This document discusses various application layer protocols. It begins with an agenda that lists OSI models, encapsulation processes, application protocol design, and specific protocols including HTTP, DNS, FTP, Telnet, DHCP, and SMTP. For each protocol, it provides details on how the protocol functions, message formats, and roles of clients and servers. The document is intended to describe key application layer protocols and their basic operations.
This ppt contains what is dhcp, it's need, advantages, disadvantages, IP address assignment process and types, DHCP architecture and lastly some differences.
The document provides an overview of the OSI model and TCP/IP networking model. It describes the seven layers of the OSI model from the physical layer to the application layer and their responsibilities in networking. It also discusses the four layers of the TCP/IP model and compares it to the OSI model. Key protocols like TCP, UDP, IP, Ethernet, and HTTP are explained in their respective layers along with functions like encapsulation and data flow between layers. Network analysis tools like Wireshark are also mentioned.
The document discusses wireless LAN standards including IEEE 802.11 and Bluetooth. It provides an overview of IEEE 802.11 specifications and architecture, addressing mechanisms, and physical layers. It also covers Bluetooth technology, describing its ad hoc network architecture and layers such as baseband and L2CAP. Various concepts are illustrated with figures including basic service sets, extended service sets, MAC layers, and frame formats.
The document discusses Point-to-Point Protocol (PPP), which provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP consists of encapsulating packets into frames, a Link Control Protocol (LCP) for establishing and configuring the connection, and Network Control Protocols (NCPs) for network layer configuration. It describes PPP frame formats, byte stuffing for transparency, and authentication protocols like PAP and CHAP. The presentation includes a Wireshark demo and addresses questions about PPP design requirements and non-requirements.
This presentation outlines the core functions of TCP - Transmission Control Protocol.
These comprise TCP Connection Control, TCP Flow Control, TCP Error Control, TCP Congestion Control, TCP Options and TCP Timers.
TCP/IP is the Internet core protocol that provides reliable, connection-oriented and stream-based communication service. Most of Internet traffic is carried in TCP connections, so scalability and reliability are crucial for a stable network on a global scale.
Overview of UDP protocol.
UDP (User Datagram Protocol) is a simple extension of the Internet Protocol services. It basically provides simple packet transport service without any quality of service functions.
Unlike TCP, UDP is connection-less and packet-based. Application PDUs (application packets) sent over a UDP socket are delivered to the receiving host application as is without fragmentation.
UDP is mostly used by applications with simple request-response communication patterns like DNS, DHCP, RADIUS, RIP or RPC.
Since UDP does provide any error recovery such as retransmission of lost packets, the application protocols have to take care of these situations.
This document discusses the evolution of Ethernet standards over multiple generations, from the original Standard Ethernet to Fast Ethernet and Gigabit Ethernet. It describes the IEEE project that established networking standards and details key changes to Ethernet like increased speeds of 100 Mbps for Fast Ethernet and 1000 Mbps for Gigabit Ethernet. Diagrams and tables illustrate different implementations and topologies for the various Ethernet standards.
This document discusses the evolution of Ethernet technology over three generations from traditional Ethernet to Fast Ethernet to Gigabit Ethernet. It describes the MAC and physical layers of each generation and shows diagrams of their frame formats, implementations, and encoding techniques. Key aspects covered include Ethernet addressing, connection methods, bandwidth sharing, bridging, switching, full-duplex operation, and standards such as 802.3.
The document describes the Internet Protocol version 4 (IPv4). It discusses the IPv4 datagram format including the header fields, fragmentation, and options. It also covers how IPv4 provides an unreliable datagram delivery service and must be paired with TCP for reliability. The document discusses security issues with IPv4 like packet sniffing, modification, and spoofing, and how IPSec can provide protection against these attacks.
This document discusses the data link layer, which prepares network layer packets for transmission by encapsulating them into frames. It identifies common data link layer protocols for both LANs and WANs. The data link layer controls media access through logical link control and media access control sublayers. Media access control methods include controlled access like token ring and contention-based access like CSMA/CD. Frame structure is also discussed, with frames containing source/destination addresses, error checking fields, and encapsulated network layer data. Different frame types are used depending on the logical and physical network topology.
This document discusses different types of computer network switching, including circuit switching, packet switching, and virtual circuit switching. Circuit switching establishes a dedicated connection between nodes for the duration of a call. Packet switching divides messages into packets that are routed independently through a network on a first-come, first-served basis without dedicated connections. Virtual circuit switching combines aspects of circuit switching and packet switching by establishing paths for packets through a three-phase process of setup, data transfer using local addressing, and teardown.
ICMP is a helper protocol that supports IP by providing error reporting and simple queries. ICMP messages are encapsulated as IP datagrams with a 4 byte header containing the type, code, and checksum. Common ICMP error messages include Destination Unreachable (sent when a datagram cannot be forwarded), Redirect (informs about a better route), and Time Exceeded (sent when the TTL reaches zero).
Ethernet is a family of networking technologies commonly used in LANs, MANs and WANs. It was first standardized in 1983 at 10 Mbps and has since been updated to support higher speeds up to 10 Gbps. Fast Ethernet runs at 100 Mbps using the same frame format as standard Ethernet. Gigabit Ethernet runs at 1 Gbps while maintaining compatibility. Ten-Gigabit Ethernet operates at 10 Gbps while keeping the same frame format as prior standards.
A switched network consists of interconnected nodes called switches that can temporarily connect devices linked to the switch. There are three main types of switching: circuit switching, datagram/packet switching, and virtual circuit switching. Circuit switching requires resource reservation and dedicates resources for the duration of a connection. Datagram switching does not reserve resources and allocates them on demand. Virtual circuit switching has aspects of both by dedicating resources only for packets belonging to the same connection. Switches can be constructed in single-stage or multistage designs, with multistage switches using fewer crosspoints.
- IPv4 addresses are 32-bit numbers that uniquely identify devices connected to the internet. IPv6 addresses are 128-bit numbers introduced to replace IPv4 due to its limited 32-bit address space running out.
- IPv4 addresses are divided into classes A, B, C based on the first bits, with each class allocating a different number of addresses. IPv6 addresses use a 128-bit address space and are written in hexadecimal colon notation.
- Network Address Translation (NAT) was introduced to allow sharing of IPv4 addresses since the available addresses were insufficient. NAT maps private IPv4 addresses to public addresses for connecting to the internet.
The document discusses various IEEE 802 standards for networking technologies including Ethernet, wireless LAN (802.11), and their variants and evolutions over time. It provides details on Ethernet standards and implementations such as 802.3, 10BASE5, 10BASE2, 10BASE-T, 10BASE-F, Fast Ethernet, and Gigabit Ethernet. It also summarizes key aspects of wireless networking standards such as 802.11 components, frame format, and physical layer specifications including FHSS, DSSS, OFDM, and associated data rates and frequencies.
Controlled access protocols allow only one node to send at a time to avoid message collisions. There are three main controlled access methods: reservation, polling, and token passing. Reservation methods divide time into intervals, with reservation frames preceding data frames to reserve slots. Polling methods involve a primary station periodically polling secondary stations for data. Token passing methods use a token frame that circulates between stations, with each station only allowed to transmit when holding the token.
Distance vector routing works by having each node maintain a routing table with the minimum distance to reach every other node. Nodes share their routing tables with immediate neighbors periodically or when changes occur, allowing each node to learn optimal routes throughout the network. Each node sends only the minimum distance and next hop information to neighbors, who update their own tables. This sharing of routing information allows all nodes to gradually learn the least-cost routes.
The document discusses various technologies used for data transmission over telephone and cable networks, including:
1. Telephone networks originally used analog circuit switching to transmit voice calls but have transitioned to separate digital data transfer and signaling networks.
2. Traditional telephone lines support dial-up modems using modulation/demodulation to transmit data within the 3000Hz bandwidth for voice calls.
3. Digital Subscriber Line (DSL) technologies like ADSL provide higher bandwidth internet over existing telephone lines by using frequencies up to 1.1MHz.
4. Cable networks originally provided unidirectional video but now support bidirectional high-speed internet using technologies like DOCSIS to share bandwidth over coaxial and fiber-opt
This document discusses various application layer protocols. It begins with an agenda that lists OSI models, encapsulation processes, application protocol design, and specific protocols including HTTP, DNS, FTP, Telnet, DHCP, and SMTP. For each protocol, it provides details on how the protocol functions, message formats, and roles of clients and servers. The document is intended to describe key application layer protocols and their basic operations.
This ppt contains what is dhcp, it's need, advantages, disadvantages, IP address assignment process and types, DHCP architecture and lastly some differences.
The document provides an overview of the OSI model and TCP/IP networking model. It describes the seven layers of the OSI model from the physical layer to the application layer and their responsibilities in networking. It also discusses the four layers of the TCP/IP model and compares it to the OSI model. Key protocols like TCP, UDP, IP, Ethernet, and HTTP are explained in their respective layers along with functions like encapsulation and data flow between layers. Network analysis tools like Wireshark are also mentioned.
The document discusses wireless LAN standards including IEEE 802.11 and Bluetooth. It provides an overview of IEEE 802.11 specifications and architecture, addressing mechanisms, and physical layers. It also covers Bluetooth technology, describing its ad hoc network architecture and layers such as baseband and L2CAP. Various concepts are illustrated with figures including basic service sets, extended service sets, MAC layers, and frame formats.
The document discusses Point-to-Point Protocol (PPP), which provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP consists of encapsulating packets into frames, a Link Control Protocol (LCP) for establishing and configuring the connection, and Network Control Protocols (NCPs) for network layer configuration. It describes PPP frame formats, byte stuffing for transparency, and authentication protocols like PAP and CHAP. The presentation includes a Wireshark demo and addresses questions about PPP design requirements and non-requirements.
This presentation outlines the core functions of TCP - Transmission Control Protocol.
These comprise TCP Connection Control, TCP Flow Control, TCP Error Control, TCP Congestion Control, TCP Options and TCP Timers.
TCP/IP is the Internet core protocol that provides reliable, connection-oriented and stream-based communication service. Most of Internet traffic is carried in TCP connections, so scalability and reliability are crucial for a stable network on a global scale.
Overview of UDP protocol.
UDP (User Datagram Protocol) is a simple extension of the Internet Protocol services. It basically provides simple packet transport service without any quality of service functions.
Unlike TCP, UDP is connection-less and packet-based. Application PDUs (application packets) sent over a UDP socket are delivered to the receiving host application as is without fragmentation.
UDP is mostly used by applications with simple request-response communication patterns like DNS, DHCP, RADIUS, RIP or RPC.
Since UDP does provide any error recovery such as retransmission of lost packets, the application protocols have to take care of these situations.
This document discusses the evolution of Ethernet standards over multiple generations, from the original Standard Ethernet to Fast Ethernet and Gigabit Ethernet. It describes the IEEE project that established networking standards and details key changes to Ethernet like increased speeds of 100 Mbps for Fast Ethernet and 1000 Mbps for Gigabit Ethernet. Diagrams and tables illustrate different implementations and topologies for the various Ethernet standards.
This document discusses the evolution of Ethernet technology over three generations from traditional Ethernet to Fast Ethernet to Gigabit Ethernet. It describes the MAC and physical layers of each generation and shows diagrams of their frame formats, implementations, and encoding techniques. Key aspects covered include Ethernet addressing, connection methods, bandwidth sharing, bridging, switching, full-duplex operation, and standards such as 802.3.
This document discusses various topics related to network layer issues in computer networks, including IPV4 addressing, classful addressing, subnetting, and supernetting. It provides examples to illustrate how to calculate the number of addresses in an IP range, extract network information from IP addresses of different classes, determine subnet masks and subnet addresses when subnetting a network, and calculate supernet masks and combine multiple class C blocks into a supernetwork. The key aspects covered are IP address notation and length, classful addressing system, subnetting and supernetting techniques, and network/subnet/supernet masks.
The document discusses IPv4 addressing in TCP/IP networking. It covers the following topics:
1. Classful addressing which divides the IPv4 address space into classes A, B, C, D, and E and assigns blocks of addresses to networks. This leads to inefficient use of addresses.
2. Classless addressing which was introduced to replace classful addressing and allow flexible subnetting to better utilize the available addresses.
3. Special addresses like network, broadcast addresses and how subnet masks are used to identify the network portion of an IP address.
4. Network address translation (NAT) which can help alleviate the depletion of available IPv4 addresses by allowing multiple devices to share a single public IP address
This document discusses Zigbee and its role in wireless sensor networks. It begins by describing how sensors have evolved from simple devices without computation or communication abilities, to sensor nodes that can process data and communicate wirelessly. It then introduces Zigbee as an important wireless communication standard developed for low data rate applications requiring long battery life. The document explains that Zigbee targets applications in areas like smart energy meters and home automation due to its low power consumption and cost. It compares Zigbee to other wireless standards like Bluetooth and Wi-Fi, noting that Zigbee is best suited for simple sensor applications. Examples of commercial Zigbee products are also provided.
Ethernet has evolved from using coaxial cable to operate at speeds of 10 Mbps to using twisted-pair copper or fiber optic cables to operate at speeds of 1 Gbps or higher. It uses CSMA/CD for media access and detects collisions using a jam signal, then devices perform a random backoff before retransmitting. Ethernet frames contain source and destination MAC addresses, length/type, data, and FCS fields, with minimum and maximum frame sizes of 64 and 1518 bytes respectively.
This document provides an overview of fiber to the x (FTTX) networks using passive optical networks (PON). It begins with an introduction to FTTX and PON technologies. It then discusses the different PON architectures including point-to-multipoint PON using optical splitters, active optical networks with dedicated fibers, and hybrid networks. The document also covers considerations for PON including bandwidth, distance, security, quality of service, and future developments in PON technologies.
The document discusses wireless local area networks (WLANs) and security. It describes WLAN concepts including ad hoc and infrastructure modes. It covers WLAN security standards such as WEP, WPA, and 802.11i. It also discusses Cisco's unified wireless solutions including mesh networks, LWAPP, and AWPP protocols.
The document discusses the history and standards of Ethernet wired local area networks (LANs). It describes the IEEE Project 802 which established standards for the physical and data link layers of major LAN protocols. It then provides details on standard Ethernet, including the MAC sublayer, frame format, address types, encoding, and physical implementations. Fast Ethernet and Gigabit Ethernet are also summarized as higher speed successors to standard Ethernet.
This document summarizes some key changes in Ethernet standards over time that enabled higher data rates and compatibility with other networks. It discusses three changes: bridged Ethernet, switched Ethernet, and full-duplex Ethernet. Bridged Ethernet divides a LAN into segments using bridges, raising bandwidth and separating collision domains. Switched Ethernet uses switches with one port per hub to further segment the network. Full-duplex Ethernet allows two devices on a link to transmit and receive simultaneously, effectively doubling bandwidth and eliminating collisions.
This document summarizes the contents of Chapter 5, which covers LANs and WLANs. Section A defines network classifications like PAN, LAN, MAN and WAN. It also describes network building blocks such as standards, devices, topology and protocols. Section B covers wired networks including Ethernet basics, equipment and setup. Section C discusses wireless networks, focusing on Bluetooth, Wi-Fi standards, equipment and setup. Section D reviews using LANs to share files, printers and potential issues. The chapter provides an overview of fundamental networking concepts.
This document summarizes key aspects of IEEE 802.11 wireless LANs. It describes wireless LAN characteristics like infrastructure-based and ad-hoc networks. It discusses components like stations, access points, and service sets. It covers protocols like CSMA/CA and RTS/CTS for medium access control. It also discusses power management, roaming, and scanning functions important for wireless mobility.
This document defines and compares different types of computer networks including local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). It describes how LANs and WANs have integrated over time through the use of networking devices like bridges, routers, and switches. It also provides an overview of network design considerations and various internet and wireless connectivity options.
The document discusses wireless LAN standards including IEEE 802.11 and Bluetooth. It describes the architecture and layers of IEEE 802.11, including the physical and data link layers. It discusses topics like basic service sets, extended service sets, CSMA/CA, frame formats, and addressing. It also covers the architecture of Bluetooth including piconets, scatternets, and the Bluetooth layers.
The document discusses the MAC sublayer in the 802.11n wireless LAN standard. It describes how the 802.11n MAC sublayer aims to improve protocol efficiency, support quality of service standards, and minimize contention overhead through techniques like selective retransmission. It also examines how the 802.11n MAC protocol operates in different modes and addresses problems like hidden and exposed nodes through physical and virtual sensing methods.
Wireless LANs can be used for LAN extension between buildings, nomadic access for mobile users, and temporary ad hoc networks. There are several wireless LAN categories including infrared, spread spectrum, and narrowband microwave networks. Infrared networks have an unlimited radio spectrum but are limited by concerns of eye safety and range. Spread spectrum networks use multiple-cell configurations with either peer-to-peer or hub-based topologies. Narrowband microwave networks can be licensed to avoid interference or use unlicensed spectrum at low power over short ranges.
The document discusses Token Bus, which combines features of Ethernet and Token Ring. It operates as a physical bus but with stations logically organized into a ring, passing a token among them. Only the station holding the token can transmit data. Token Bus was limited to industrial applications and saw no commercial use for data communication. It uses the token passing mechanism over a physical bus topology at the data link layer.
The document discusses the evolution of Ethernet networking standards over time. It describes how IEEE Project 802 was started in 1985 to set standards for interconnecting equipment from different manufacturers. It then provides details on the original Standard Ethernet created in 1976 and its subsequent generations. The document also outlines changes to Standard Ethernet like bridging and switching. It discusses the Fast Ethernet and Gigabit Ethernet standards that succeeded Standard Ethernet by providing higher data rates of 100 Mbps and 1000 Mbps respectively.
Carrier Ethernet provides standardized, carrier-class Ethernet services on a global scale. It builds upon Metro Ethernet by expanding the services to cover worldwide networks traversing multiple countries and access networks. Carrier Ethernet is defined by five key attributes that distinguish it from traditional LAN-based Ethernet: it provides standardized services across multiple networks; can scale to support millions of nodes and high bandwidths; offers reliable service with fast protection from link failures; ensures quality of service through service level agreements; and manages services through centralized operations support systems.
The document discusses different generations of wired local area network (LAN) technologies, starting with Standard Ethernet. It describes Standard Ethernet's characteristics, including its addressing mechanism, CSMA/CD access method, efficiency of around 39%, and popular implementations using coaxial cable or twisted-pair wiring operating at 10 megabits per second. The document also briefly outlines Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet as evolutions of the original Standard Ethernet specification that increased supported speeds over time.
This document discusses the evolution of Ethernet standards over multiple generations, from the original Standard Ethernet to Fast Ethernet and Gigabit Ethernet. It describes the IEEE project that established networking standards and details key changes to Ethernet like increased speeds of 100 Mbps for Fast Ethernet and 1000 Mbps for Gigabit Ethernet. Diagrams and tables illustrate different implementations and topologies for the various Ethernet standards.
This document discusses the evolution of Ethernet standards over multiple generations from the original Ethernet created at Xerox PARC to modern Gigabit and Ten-Gigabit Ethernet standards. It covers the work of the IEEE 802 committee to establish standards enabling interoperability among networking equipment from different manufacturers. Key standards discussed include the original 10 Mbps Standard Ethernet, the 100 Mbps Fast Ethernet standard 802.3u, and the 1 Gbps and 10 Gbps Gigabit Ethernet standards 802.3z and beyond. The document includes diagrams illustrating Ethernet frame formats, addressing schemes, cable types and network topologies for different generations of Ethernet standards.
This document discusses the evolution of Ethernet standards over multiple generations from the original Ethernet created in 1976 to modern Gigabit Ethernet. It describes the work of IEEE Project 802 to set standards enabling interoperability among networking equipment from different manufacturers. Key standards discussed include the original 10 Mbps Standard Ethernet, as well as faster variants like Fast Ethernet operating at 100 Mbps, Gigabit Ethernet at 1 Gbps, and Ten-Gigabit Ethernet. The physical layer and data link layer are examined along with changes to Ethernet like bridging, switching, and full-duplex operation that increased speed and supported higher data rates over time.
The document discusses the evolution of Ethernet standards over time from the original Ethernet created in 1976 to modern gigabit Ethernet. It covers the IEEE 802 project to standardize LAN protocols and the development of standard Ethernet, fast Ethernet, and gigabit Ethernet. Key aspects summarized include the purpose of IEEE project 802, the development of Ethernet through four generations to support higher data rates, and summaries of the implementations and encoding for standard, fast, and gigabit Ethernet variants.
The document discusses the evolution of Ethernet networking standards over time. It begins with the original Ethernet created in 1976 and the IEEE 802 project launched in 1985 to set standards. Key standards discussed include Standard Ethernet from 10 Mbps to 100 Mbps Fast Ethernet to 1 Gbps Gigabit Ethernet. The standards define the data link and physical layers and underwent changes like bridging, switching, and full duplex to support higher speeds and larger networks while maintaining backward compatibility.
The document discusses the evolution of Ethernet networking standards established by the IEEE. It describes the original Ethernet standard from 1976 and its four generations. It then discusses how standards were developed under Project 802 to enable interoperability between networking equipment from different manufacturers. Key standards discussed include Standard Ethernet, Fast Ethernet, Gigabit Ethernet, and Ten-Gigabit Ethernet, along with their different implementations and topology options. The standards define aspects of the physical and data link layers to support higher networking speeds and capabilities.
This document discusses Ethernet networking concepts and technologies. It provides an overview of the history and development of Ethernet, including the ALOHA network and the development of Ethernet II and IEEE 802.3 standards. The key differences between Ethernet II and IEEE 802.3 are described, such as frame formats, transceiver issues, and topological support. Manchester encoding is explained as a method used in Ethernet to detect transmission errors. Details are also given about the datalink layer, address formats, and the various 10 Mbps Ethernet specifications defined by IEEE 802.3.
Ethernet is a widely used local area network technology that operates at the Physical and Data Link layers of the OSI model. It uses CSMA/CD access method to share the transmission medium and detect collisions. Key Ethernet standards include 10Base-T, 100Base-TX, 1000Base-T, and 10GBase-T for copper cable, as well as 100Base-FX and 1000Base-LX for fiber-optic cable. Switches help improve network performance by segmenting collision domains and enabling full-duplex transmissions.
Ethernet uses CSMA/CD access method where nodes can sense carrier and detect collisions. It was first defined in 1978 and formed basis for IEEE 802.3 standard. It uses exponential backoff to retry transmission after collisions and is limited to 2500m to ensure collisions can be detected. Ethernet addresses are unique to each adapter and frames contain fields for source, destination, data and error checking.
This document provides an overview of Ethernet network fundamentals, including:
- The OSI model layers that Ethernet operates in (physical and data link layers)
- Key components and functions of Ethernet including frames, addressing, and the CSMA/CD media access method
- The evolution of Ethernet from early implementations using coaxial cable to modern switched networks using fiber optics and speeds of 1Gbps+
- How MAC addresses are used to uniquely identify devices on an Ethernet network
The document describes a method for calculating the frame check sequence (FCS) in tagged Ethernet frames. It begins by providing background on FCS and how it is used to detect errors in Ethernet frames. It then discusses IEEE 802.1Q tagging, which inserts additional fields into frames to support features like VLANs. The key proposal is a method to calculate the FCS for a tagged frame efficiently based on the FCS already calculated for the original frame, since they contain mostly the same information. This involves expressing the frames as polynomials and using properties of cyclic redundancy codes to derive a relationship between the FCS values.
The document presents a method for calculating frame check sequences (FCS) in tagged Ethernet frames. It begins with background on FCS and IEEE 802.1Q tagging. It then proposes a method to calculate the FCS of a tagged frame using the FCS of the original frame. The method expresses the original and tagged frames as polynomials and shows that the FCS of a tagged frame can be obtained by adding a precalculated value to the FCS of the original frame. Examples are provided to demonstrate the method. The method allows for faster FCS calculation compared to other methods and is particularly useful for applications with low latency tolerances like voice over IP.
The Ethernet frame has a standard structure that defines fields like the destination address, source address, and optional Q-Tag for VLAN tagging. It began as defined in the DIX standard and was later modified by IEEE 802.3, with the key change being whether the type/length field defined type or length. The frame structure allows interfaces to read frames by destination address and ignore unwanted traffic. The preamble provides synchronization and the addresses define unicast, multicast, or broadcast traffic with the first bits of each address field.
In 1985, the Computer Society of the IEEE started a project, called Project 802, to set standards and to enable inter communication among equipment from a variety of manufacturers.
Project 802 is a way of specifying functions of the physical layer and the data link layer of major LAN protocols.
Introducing BoxLang : A new JVM language for productivity and modularity!Ortus Solutions, Corp
Just like life, our code must adapt to the ever changing world we live in. From one day coding for the web, to the next for our tablets or APIs or for running serverless applications. Multi-runtime development is the future of coding, the future is to be dynamic. Let us introduce you to BoxLang.
Dynamic. Modular. Productive.
BoxLang redefines development with its dynamic nature, empowering developers to craft expressive and functional code effortlessly. Its modular architecture prioritizes flexibility, allowing for seamless integration into existing ecosystems.
Interoperability at its Core
With 100% interoperability with Java, BoxLang seamlessly bridges the gap between traditional and modern development paradigms, unlocking new possibilities for innovation and collaboration.
Multi-Runtime
From the tiny 2m operating system binary to running on our pure Java web server, CommandBox, Jakarta EE, AWS Lambda, Microsoft Functions, Web Assembly, Android and more. BoxLang has been designed to enhance and adapt according to it's runnable runtime.
The Fusion of Modernity and Tradition
Experience the fusion of modern features inspired by CFML, Node, Ruby, Kotlin, Java, and Clojure, combined with the familiarity of Java bytecode compilation, making BoxLang a language of choice for forward-thinking developers.
Empowering Transition with Transpiler Support
Transitioning from CFML to BoxLang is seamless with our JIT transpiler, facilitating smooth migration and preserving existing code investments.
Unlocking Creativity with IDE Tools
Unleash your creativity with powerful IDE tools tailored for BoxLang, providing an intuitive development experience and streamlining your workflow. Join us as we embark on a journey to redefine JVM development. Welcome to the era of BoxLang.
Enterprise Knowledge’s Joe Hilger, COO, and Sara Nash, Principal Consultant, presented “Building a Semantic Layer of your Data Platform” at Data Summit Workshop on May 7th, 2024 in Boston, Massachusetts.
This presentation delved into the importance of the semantic layer and detailed four real-world applications. Hilger and Nash explored how a robust semantic layer architecture optimizes user journeys across diverse organizational needs, including data consistency and usability, search and discovery, reporting and insights, and data modernization. Practical use cases explore a variety of industries such as biotechnology, financial services, and global retail.
MongoDB vs ScyllaDB: Tractian’s Experience with Real-Time MLScyllaDB
Tractian, an AI-driven industrial monitoring company, recently discovered that their real-time ML environment needed to handle a tenfold increase in data throughput. In this session, JP Voltani (Head of Engineering at Tractian), details why and how they moved to ScyllaDB to scale their data pipeline for this challenge. JP compares ScyllaDB, MongoDB, and PostgreSQL, evaluating their data models, query languages, sharding and replication, and benchmark results. Attendees will gain practical insights into the MongoDB to ScyllaDB migration process, including challenges, lessons learned, and the impact on product performance.
Conversational agents, or chatbots, are increasingly used to access all sorts of services using natural language. While open-domain chatbots - like ChatGPT - can converse on any topic, task-oriented chatbots - the focus of this paper - are designed for specific tasks, like booking a flight, obtaining customer support, or setting an appointment. Like any other software, task-oriented chatbots need to be properly tested, usually by defining and executing test scenarios (i.e., sequences of user-chatbot interactions). However, there is currently a lack of methods to quantify the completeness and strength of such test scenarios, which can lead to low-quality tests, and hence to buggy chatbots.
To fill this gap, we propose adapting mutation testing (MuT) for task-oriented chatbots. To this end, we introduce a set of mutation operators that emulate faults in chatbot designs, an architecture that enables MuT on chatbots built using heterogeneous technologies, and a practical realisation as an Eclipse plugin. Moreover, we evaluate the applicability, effectiveness and efficiency of our approach on open-source chatbots, with promising results.
ScyllaDB Leaps Forward with Dor Laor, CEO of ScyllaDBScyllaDB
Join ScyllaDB’s CEO, Dor Laor, as he introduces the revolutionary tablet architecture that makes one of the fastest databases fully elastic. Dor will also detail the significant advancements in ScyllaDB Cloud’s security and elasticity features as well as the speed boost that ScyllaDB Enterprise 2024.1 received.
An All-Around Benchmark of the DBaaS MarketScyllaDB
The entire database market is moving towards Database-as-a-Service (DBaaS), resulting in a heterogeneous DBaaS landscape shaped by database vendors, cloud providers, and DBaaS brokers. This DBaaS landscape is rapidly evolving and the DBaaS products differ in their features but also their price and performance capabilities. In consequence, selecting the optimal DBaaS provider for the customer needs becomes a challenge, especially for performance-critical applications.
To enable an on-demand comparison of the DBaaS landscape we present the benchANT DBaaS Navigator, an open DBaaS comparison platform for management and deployment features, costs, and performance. The DBaaS Navigator is an open data platform that enables the comparison of over 20 DBaaS providers for the relational and NoSQL databases.
This talk will provide a brief overview of the benchmarked categories with a focus on the technical categories such as price/performance for NoSQL DBaaS and how ScyllaDB Cloud is performing.
QA or the Highway - Component Testing: Bridging the gap between frontend appl...zjhamm304
These are the slides for the presentation, "Component Testing: Bridging the gap between frontend applications" that was presented at QA or the Highway 2024 in Columbus, OH by Zachary Hamm.
QR Secure: A Hybrid Approach Using Machine Learning and Security Validation F...AlexanderRichford
QR Secure: A Hybrid Approach Using Machine Learning and Security Validation Functions to Prevent Interaction with Malicious QR Codes.
Aim of the Study: The goal of this research was to develop a robust hybrid approach for identifying malicious and insecure URLs derived from QR codes, ensuring safe interactions.
This is achieved through:
Machine Learning Model: Predicts the likelihood of a URL being malicious.
Security Validation Functions: Ensures the derived URL has a valid certificate and proper URL format.
This innovative blend of technology aims to enhance cybersecurity measures and protect users from potential threats hidden within QR codes 🖥 🔒
This study was my first introduction to using ML which has shown me the immense potential of ML in creating more secure digital environments!
ScyllaDB is making a major architecture shift. We’re moving from vNode replication to tablets – fragments of tables that are distributed independently, enabling dynamic data distribution and extreme elasticity. In this keynote, ScyllaDB co-founder and CTO Avi Kivity explains the reason for this shift, provides a look at the implementation and roadmap, and shares how this shift benefits ScyllaDB users.
CNSCon 2024 Lightning Talk: Don’t Make Me Impersonate My IdentityCynthia Thomas
Identities are a crucial part of running workloads on Kubernetes. How do you ensure Pods can securely access Cloud resources? In this lightning talk, you will learn how large Cloud providers work together to share Identity Provider responsibilities in order to federate identities in multi-cloud environments.
Elasticity vs. State? Exploring Kafka Streams Cassandra State StoreScyllaDB
kafka-streams-cassandra-state-store' is a drop-in Kafka Streams State Store implementation that persists data to Apache Cassandra.
By moving the state to an external datastore the stateful streams app (from a deployment point of view) effectively becomes stateless. This greatly improves elasticity and allows for fluent CI/CD (rolling upgrades, security patching, pod eviction, ...).
It also can also help to reduce failure recovery and rebalancing downtimes, with demos showing sporty 100ms rebalancing downtimes for your stateful Kafka Streams application, no matter the size of the application’s state.
As a bonus accessing Cassandra State Stores via 'Interactive Queries' (e.g. exposing via REST API) is simple and efficient since there's no need for an RPC layer proxying and fanning out requests to all instances of your streams application.
MySQL InnoDB Storage Engine: Deep Dive - MydbopsMydbops
This presentation, titled "MySQL - InnoDB" and delivered by Mayank Prasad at the Mydbops Open Source Database Meetup 16 on June 8th, 2024, covers dynamic configuration of REDO logs and instant ADD/DROP columns in InnoDB.
This presentation dives deep into the world of InnoDB, exploring two ground-breaking features introduced in MySQL 8.0:
• Dynamic Configuration of REDO Logs: Enhance your database's performance and flexibility with on-the-fly adjustments to REDO log capacity. Unleash the power of the snake metaphor to visualize how InnoDB manages REDO log files.
• Instant ADD/DROP Columns: Say goodbye to costly table rebuilds! This presentation unveils how InnoDB now enables seamless addition and removal of columns without compromising data integrity or incurring downtime.
Key Learnings:
• Grasp the concept of REDO logs and their significance in InnoDB's transaction management.
• Discover the advantages of dynamic REDO log configuration and how to leverage it for optimal performance.
• Understand the inner workings of instant ADD/DROP columns and their impact on database operations.
• Gain valuable insights into the row versioning mechanism that empowers instant column modifications.
Discover the Unseen: Tailored Recommendation of Unwatched ContentScyllaDB
The session shares how JioCinema approaches ""watch discounting."" This capability ensures that if a user watched a certain amount of a show/movie, the platform no longer recommends that particular content to the user. Flawless operation of this feature promotes the discover of new content, improving the overall user experience.
JioCinema is an Indian over-the-top media streaming service owned by Viacom18.
Supercell is the game developer behind Hay Day, Clash of Clans, Boom Beach, Clash Royale and Brawl Stars. Learn how they unified real-time event streaming for a social platform with hundreds of millions of users.
2. 13-1 IEEE STANDARDS In 1985, the Computer Society of the IEEE started a project, called Project 802, to set standards to enable intercommunication among equipment from a variety of manufacturers. Project 802 is a way of specifying functions of the physical layer and the data link layer of major LAN protocols. The relationship of the 802 Standard to the traditional OSI model is shown in Figure 13.1. The IEEE has subdivided the data link layer into two sublayers: logical link control (LLC) and media access control (MAC). IEEE has also created several physical layer standards for different LAN protocols. Figure 13.1 IEEE standard for LANs
3. Figure 13.2 HDLC frame compared with LLC and MAC frames Framing LLC defines a protocol data unit (PDU) that is somewhat similar to that of HDLC. The header contains a control field like the one in HDLC; this field is used for flow and error control. The two other header fields define the upper-layer protocol at the source and destination that uses LLC. These fields are called the destination service access point (DSAP) and the source service access point (SSAP). The other fields defined in a typical data link control protocol such as HDLC are moved to the MAC sublayer. In other words, a frame defined in HDLC is divided into a PDU at the LLC sublayer and a frame at the MAC sublayer, as shown in Figure 13.2.
4. 13-2 STANDARD ETHERNET The original Ethernet was created in 1976 at Xerox’s Palo Alto Research Center (PARC). Since then, it has gone through four generations. We briefly discuss the Standard (or traditional) Ethernet in this section. Figure 13.3 Ethernet evolution through four generations MAC Sublayer In Standard Ethernet, the MAC sublayer governs the operation of the access method. It also frames data received from the upper layer and passes them to the physical layer. Frame Format The Ethernet frame contains seven fields: preamble, SFD, DA, SA, length or type of protocol data unit (PDU), upper-layer data, and the CRC. Ethernet does not provide any mechanism for acknowledging received frames, making it what is known as an unreliable medium. Acknowledgments must be implemented at the higher layers. The format of the MAC frame is shown in Figure 13.4.
5. Figure 13.4 802.3 MAC frame Destination address (DA). The DA field is 6 bytes and contains the physical address of the destination station or stations to receive the packet. Preamble . of alternating Os and 1 s that alerts the receiving system to the coming frame and enables it to synchronize its input timing. The pattern provides only an alert and a timing pulse. The preamble is actually added at the physical layer and is not (formally) part of the frame. Start frame delimiter (SFD). signals the beginning of the frame. The SFD warns the station or stations that this is the last chance for synchronization. The last 2 bits is 11 and alerts the receiver that the next field is the destination address. Source address (SA). contains the physical address of the sender of the packet. Length or type. This field is defined as a type field or length field. The original Ethernet used this field as the type field to define the upper-layer protocol using the MAC frame. The IEEE standard used it as the length field to define the number of bytes in the data field. Both uses are common today. Data. This field carries data encapsulated from the upper-layer protocols. CRC. The last field contains error detection information, in this case a CRC-32
6. Figure 13.5 Minimum and maximum lengths The minimum length restriction is required for the correct operation of CSMA/CD. An Ethernet frame needs to have a minimum length of 512 bits or 64 bytes. Part of this length is the header and the trailer. The standard defines the maximum length of a frame (without preamble and SFD field) as 1518 bytes. If we subtract the 18 bytes of header and trailer, the maximum length of the payload is 1500 bytes. The maximum length restriction has two historical reasons . First , memory was very expensive when Ethernet was designed: a maximum length restriction helped to reduce the size of the buffer. Second , the maximum length restriction prevents one station from monopolizing the shared medium, blocking other stations that have data to send.
7. Figure 13.6 Example of an Ethernet address in hexadecimal notation Addressing Each station on an Ethernet network (such as a PC, workstation, or printer) has its own network interface card (NIC). The NIC fits inside the station and provides the station with a 6-byte physical address. As shown in Figure 13.6, the Ethernet address is 6 bytes (48 bits), normally written in hexadecimal notation, with a colon between the bytes. Unicast, Multicast, and Broadcast Addresses A source address is always a unicast address--the frame comes from only one station. The destination address, however, can be unicast, multicast, or broadcast. Figure 13.7 shows how to distinguish a unicast address from a multicast address. If the least significant bit of the first byte in a destination address is 0, the address is unicast; otherwise, it is multicast. Figure 13.7 Unicast and multicast addresses
8.
9. Figure 13.8 Categories of Standard Ethernet Figure 13.10 10Base5 implementation -Thick Ethernet 10Base5 was the first Ethernet specification to use a bus topology with an external transceiver (transmitter/receiver) connected via a tap to a thick coaxial cable. The transceiver is responsible for transmitting, receiving, and detecting collisions. The transceiver is connected to the station via a transceiver cable that provides separate paths for sending and receiving. This means that collision can only happen in the coaxial cable.
10. also uses a bus topology, but the cable is much thinner and more flexible. The cable can be bent to pass very close to the stations. In this case, the transceiver is normally part of the network interface card (NIC), which is installed inside the station. Note that the collision here occurs in the thin coaxial cable. This implementation is more cost effective than 10Base5 because thin coaxial cable is less expensive than thick coaxial and the tee connections are much cheaper than taps. Installation is simpler because the thin coaxial cable is very flexible. Figure 13.11 10Base2 implementation - Thin Ethernet or Cheapernet. Figure 13.12 10Base-T implementation - Twisted-Pair Ethernet
11. Uses a physical star topology. The stations are connected to a hub via two pairs of twisted cable. Note that two pairs of twisted cable create two paths (one for sending and one for receiving) between the station and the hub. Any collision here happens in the hub. Compared to 10Base5 or 10Base2, we can see that the hub actually replaces the coaxial cable as far as a collision is concerned. Figure 13.13 10Base-F implementation - Fiber Ethernet uses a star topology to connect stations to a hub. The stations are connected to the hub using two fiber-optic cables. Table 13.1 Summary of Standard Ethernet implementations
12. 13-3 CHANGES IN THE STANDARD The 10-Mbps Standard Ethernet has gone through several changes before moving to the higher data rates. These changes actually opened the road to the evolution of the Ethernet to become compatible with other high-data-rate LANs. Topics discussed in this section: Bridged Ethernet; Switched Ethernet; Full-Duplex Ethernet. Bridged Ethernet The first step in the Ethernet evolution was the division of a LAN by bridges. Bridges have two effects on an Ethernet LAN: They raise the bandwidth and they separate collision domains. In an unbridged Ethernet network, the total capacity (10 Mbps) is shared among all stations with a frame to send; the stations share the bandwidth of the network. If only one station has frames to send, it benefits from the total capacity (10 Mbps). But if more than one station needs to use the network, the capacity is shared. For example, if two stations have a lot of frames to send, they probably alternate in usage. When one station is sending, the other one refrains from sending. We can say that, in this case, each station on average, sends at a rate of 5 Mbps. Figure 13.14 shows the situation.
13. A bridge divides the network into two or more networks. Bandwidth-wise, each network is independent. For example, in Figure 13.15, a network with 12 stations is divided into two networks, each with 6 stations. Now each network has a capacity of 10 Mbps. The 10-Mbps capacity in each segment is now shared between 6 stations (actually 7 because the bridge acts as a station in each segment), not 12 stations. In a network with a heavy load, each station theoretically is offered 10/6 Mbps instead of 10/12 Mbps, assuming that the traffic is not going through the bridge. You can see that the collision domain becomes much smaller and the probability of collision is reduced tremendously. Figure 13.16 Collision domains in an unbridged network and a bridged network
14. Switched Ethernet: The idea of a bridged LAN can be extended to a switched LAN. Instead of having two to four networks, why not have N networks, where N is the number of stations on the LAN? In other words, if we can have a multiple-port bridge, why not have an N-port switch? In this way, the bandwidth is shared only between the station and the switch (5 Mbps each). In addition, the collision domain is divided into N domains. A layer 2 switch is an N-port bridge with additional sophistication that allows faster handling of the packets. Evolution from a bridged Ethernet to a switched Ethernet was a big step that opened the way to an even faster Ethernet, as we will see. Figure 13.17 shows a switched LAN. Full-Duplex Ethernet: One of the limitations of 10Base5 and 10Base2 is that communication is half-duplex (10Base-T is always full-duplex); a station can either send or receive, but may not do both at the same time. The next step in the evolution was to move from switched Ethernet to full-duplex switched Ethernet. The full-duplex mode increases the capacity of each domain from 10 to 20 Mbps.Figure13.18 shows a switched Ethernet in full-duplex mode. Note that instead of using one link between the station and the switch, the configuration uses two links: one to transmit and one to receive.
15. No Need for CSMA/CD In full-duplex switched Ethernet, there is no need for the CSMA/CD method. In a full- duplex switched Ethernet, each station is connected to the switch via two separate links. Each station or switch can send and receive independently without worrying about collision. Each link is a point-to-point dedicated path between the station and the switch. There is no longer a need for carrier sensing; there is no longer a need for collision detection. The job of the MAC layer becomes much easier. The carrier sensing and collision detection functionalities of the MAC sublayer can be turned off. MAC Control Layer Standard Ethernet was designed as a connectionless protocol at the MAC sublayer. There is no explicit flow control or error control to inform the sender that the frame has arrived at the destination without error. When the receiver receives the frame, it does not send any positive or negative acknowledgment. To provide for flow and error control in full-duplex switched Ethernet, a new sublayer, called the MAC control, is added between the LLC sublayer and the MAC sublayer.
16. 13-4 FAST ETHERNET Fast Ethernet was designed to compete with LAN protocols such as FDDI or Fiber Channel. IEEE created Fast Ethernet under the name 802.3u. Fast Ethernet is backward-compatible with Standard Ethernet, but it can transmit data 10 times faster at a rate of 100 Mbps. The goals of Fast Ethernet can be summarized as follows: 1. Upgrade the data rate to 100 Mbps. 2. Make it compatible with Standard Ethernet. 3. Keep the same 48-bit address. 4. Keep the same frame format. 5. Keep the same minimum and maximum frame lengths. MAC Sublayer: A main consideration in the evolution of Ethernet from 10 to 100 Mbps was to keep the MAC sublayer untouched. However, a decision was made to drop the bus topologies and keep only the star topology. For the star topology, there are two choices , as we saw before: half duplex and full duplex. In the half-duplex approach, the stations are connected via a hub; in the full-duplex approach, the connection is made via a switch with buffers at each port. Autonegotiation: A new feature added to Fast Ethernet is called autonegotiation. It allows a station or a hub a range of capabilities. Autonegotiation allows two devices to negotiate the mode or data rate of operation. It was designed particularly for the following purposes:1. To allow incompatible devices to connect to one another. For example, a device with a maximum capacity of 10 Mbps can communicate with a device with a 100 Mbps capacity (but can work at a lower rate). 2. To allow one device to have multiple capabilities. 3. To allow a station to check a hub's capabilities.
17. Physical Layer: The physical layer in Fast Ethernet is more complicated than the one in Standard Ethernet. We briefly discuss some features of this layer. Topology Fast Ethernet is designed to connect two or more stations together. If there are only two stations, they can be connected point-to-point. Three or more stations need to be con- nected in a star topology with a hub or a switch at the center, as shown in Figure 13.19. Figure 13.20 Fast Ethernet implementations
18. Figure 13.21 Encoding for Fast Ethernet implementation Table 13.2 Summary of Fast Ethernet implementations
19. 13-5 GIGABIT ETHERNET The need for an even higher data rate resulted in the design of the Gigabit Ethernet protocol (1000 Mbps). The IEEE committee calls the standard 802.3z. In the full-duplex mode of Gigabit Ethernet, there is no collision; the maximum length of the cable is determined by the signal attenuation in the cable. Topology Gigabit Ethernet is designed to connect two or more stations. If there are only two stations, they can be connected point-to-point. Three or more stations need to be connected in a star topology with a hub or a switch at the center. Another possible configuration is to connect several star topologies or let a star topology be part of another as shown in Figure 13.22.
21. Table 13.3 Summary of Gigabit Ethernet implementations Table 13.4 Summary of Ten-Gigabit Ethernet implementations MAC Sublayer Ten-Gigabit Ethernet operates only in full duplex mode which means there is no need for contention; CSMA/CD is not used in Ten-Gigabit Ethernet. Physical Layer The physical layer in Ten-Gigabit Ethernet is designed for using fiber-optic cable over long distances. Three implementations are the most common: lOGBase-S, lOGBase-L, and 10GBase-E. Table 13.4 shows a summary of the Ten-Gigabit Ethernet implementaions.