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LINUX NETWORKINGTOPIC 6.0Internet Protocol (IP) in UDP/IP and TCP/IPIP is the network layerpacket delivery service (host-to-host).translation between different data-link protocols.

IP DATAGRAMSIP provides connectionless, unreliable delivery of IP datagrams.Connectionless: each datagram is independent of all others.Unreliable: there is no guarantee that datagrams are delivered correctly or at all.

IP ADDRESSESIP is a network layer - it must be capable of providing communication between hosts on different kinds of networks (different data-link implementations).The address must include information about what network the receiving host is on. This makes routing feasible.

IP ADDRESSESIP addresses are logical addresses (not physical)32 bits.Includes a network ID and a host ID.Every host must have a unique IP address.IP addresses are assigned by a central authority (Internet Corporation for Assigned Names and Numbers -- ICANN)

SERVICES PROVIDED BY IPConnectionless Delivery (each datagram is treated individually).Unreliable (delivery is not guaranteed).Fragmentation / Reassembly (based on hardware MTU).Routing.Error detection.

IP DATAGRAM FRAGMENTATIONEach fragment (packet) has the same structure as the IP datagram. IP specifies that datagram reassembly is done only at the destination (not on a hop-by-hop basis).If any of the fragments are lost - the entire datagram is discarded (and an ICMP message is sent to the sender).

UDP (USER DATAGRAM PROTOCOL)UDP is a transport-layer protocolcommunication between processes

UDP uses IP to deliver datagrams to the right host.PORTSUDP/IP uses an abstract destination point called a protocol port.Ports are identified by a positive integer.Operating systems provide some mechanism that processes use to specify a port.

PORTSHost AHost BProcessProcessProcessProcessProcessProcessUDP FeaturesDatagram DeliveryConnectionlessUnreliableHalf-duplexSource PortDestination PortLengthChecksumDataUDP Datagram FormatTCP (Transmission Control Protocol)TCP is an alternative transport layer protocol supported by TCP/IP.TCP provides:Byte-StreamConnection-orientedReliableFull-duplexTCP vs. UDPQ: Which protocol is better ?A: It depends on the application.

TCP provides a connection-oriented, reliable byte stream service (lots of overhead).

UDP offers minimal datagram delivery service (as little overhead as possible).

IPX / SPXInternetwork Packet Exchange/Sequenced Packet Exchangenetworks using the Novell NetWare OS.IPX is a network layer protocolSPX is a transport layer protocolIPX having similarities to IPSPX having similarities to TCPIPX / SPX (cont..)Novell's UnixWare supported IPX/SPX natively.Open Enterprise Server Linux: does not support IPX/SPX (have to use an additional software package)Open source FreeBSD OS includes an IPX/SPX stackAppleTalkproprietary suite of protocols developed by Apple Inc.included in the original Macintosh released in 1984.corresponds closely to the Network layer

NETWORKING MODEL FOR AppleTalkOSI ModelCorresponding AppleTalk layersApplicationApple Filing Protocol (AFP)PresentationApple Filing Protocol (AFP)SessionZone Information Protocol (ZIP), AppleTalk Session Protocol (ASP), AppleTalk Data Stream Protocol (ADSP)TransportAppleTalk Transaction Protocol (ATP), AppleTalk Echo Protocol (AEP), Name Binding Protocol (NBP), Routing Table Maintenance Protocol (RTMP)NetworkDatagram Delivery Protocol (DDP)Data linkEtherTalk Link Access Protocol (ELAP), LocalTalk Link Access Protocol (LLAP)TokenTalk Link Access Protocol (TLAP), Fiber Distributed Data Interface (FDDI)PhysicalLocalTalk driver, Ethernet driver, Token Ring driver, FDDI driverDLC (Down able Contents)is a form of digital media distributed through the Internet.used to refer specifically to content created for video games that is released separately from the main video game release.Or used to refer to any type of digital entertainment media distributed online.allowed users to download games using a telephone line or over the cable line.

DECneta suite of network protocols created by Digital Equipment Corporation1975 - peer-to-peer network architectures (built for 4 layers)1980 - transforming DEC into a networking powerhouse1982 - evolved into a 7 layer OSI compliant networking protocol2010 - an open-source version has been developed for the Linux OS. DECnet code has been embedded in the Linux kernel

DECnet PHASE IV PROTOCOL SUITELayersCorresponding ProtocolsApplicationDAP: Data Access ProtocolCTERM: Command TerminalNetwork ManagementNICE: Network Information & Control ExchangeMOP: Maintenance Operation ProtocolSessionSCP: Session Control ProtocolTransportNSP: Network Service ProtocolNetworkDRP: DECnet Routing ProtocolData linkDDCMP: Digital Data Communications Message ProtocolPhysicalEthernet, Token ring, FDDI,NIC (Network Interface Card)is a hardware device that handles an interface to a computer networkallows a network-capable device to access that network. has a ROM chip that contains a MAC Addressexists on the Data Link Layer of the OSI model NIC (Network Interface Card)4 techniques NIC used to transfer data:Polling (microprocessor examines the status of the peripheral under program control)Programmed I/O (microprocessor alerts the designated peripheral by applying its address to the system's address bus)Interrupt-driven I/O (peripheral alerts the microprocessor that it's ready to transfer data)DMA (intelligent peripheral assumes control of the system bus to access memory directly - removes load from the CPU but requires a separate processor on the card)COMMANDSpingifconfigdhclient

ping COMMANDis a computer network administration utility used to test the reach ability of a host on an Internet Protocol (IP) network to measure the round-trip time for messages sent from the originating host to a destination computer.operates by sending Internet Control Message Protocol (ICMP) echo request packetsUsed as a tool to troubleshoot problems in an IP network. ifconfig COMMANDshort for interface configurationIt is a system administration utility in Unix-like operating systems to configure, control, and query TCP/IP network interface parameters originally appeared in 4.2BSD as part of the BSD TCP/IP suite.setting an interface's IP address and netmask, and disabling or enabling a given interfaceto display and analyze network interface parameters.