Advanced Networks Revision (Bournemouth Uni)

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Adv. NetInternet Protocol (IP)IPv62^128 addressesFirst 64bits used as network addressSecond 64bits host addressNo CIDR SubnettingPacket size up to 64KBNo fragmentation - Makes use of Path MTU ...HeaderFixed HeaderVersionTraffic classFlow label (QoS management)Payload LengthNext headerSpecifies next encapsulated header --or- ...Specifies presence of extension headersHop limitSource AddressDestination AddressExtension HeaderContext-specific headersOne or more can be includedExamplesRoutingFragmentationAuthentication (IPsec)Destination optionsIPv42^32 AddressCIDR subnettingHeaderVersionHeader lengthDiffServ (QoS)Total LengthIdentificationFlagsReserved, must be 0Don't FragmentMore FragmentsFragment offsetTTLProtocolChecksumSource addressDestination addressFragmentationIf datagram is larger than MTU then pack ...More fragment flag indicates if there ar ...Fragment offset indicates how many fragm ...Don't fragment flag will make datagrams ...Wireless802.11Legacy2.4GHz band1 - 2 MbpsFHSS (Frequency Hopping Spread Spectrum)DSSS (Direct Sequence Spread Spectrum)A54Mbps5GHz ISM BandShort range (30m)OFDMB2.4GHzGreater range (90m)11MbpsBetter modulation than 1997DSSS/FHSSG54Mbps90m rangeOFDM (with compatibility for B)N2.4GHz and 5GHzUpto 600Mbps (144 achievable)Multi In Multi Out (MIMO)250m rangeWiMAXWorldwide Interoperability for Microwave ...IEEE 802.16-2004 fixed infrastructureScalable Orthogonal Frequency Division M ...802.16e supports mobile devicesUpto 74MbpsUpto 10 miles w/Line of Sight5 Miles non Line of SightZigbeeLow powerWireless meshOperates at 868MHz, 2.4GHzBinary Phase Shift Keying (BPSK) at 868M ...Quadrature Phase Shift Keying (QPSK) at ...20Kbps @ 868MHz250Kbps @ 2.4GHzRange 10 - 75mLow latency from sleepIncompatible with GPL and many FOSS Lice ...DevicesZigBee Co-ordinator (ZC)Root of networkBridge to other networksOnly one per networkTrust Center and Key RepositoryZigBee Router (ZR)Application functionActs as a mesh nodeZigBee End Device (ZED)No RoutingVery little hardwarePushes data onto networkDirect Sequence Spread Spectrum (DSSS)Carrier Sense Multiple Access/Collision ...CellularLayer 4 ProtocolsTCPConnection OrientatedTransmission Control ProtocolTCP HandshakeSYN flag setRandom SYN number setSYN segment transmittedReciever responds with ACK and SYN +1Reliable datagram deliveryApplicationsWeb browsingEmailBursty dataData which requires reliabilitySliding Window MechanismCertain number of bytes are transmitted ...Window size negotiated with recieverWhen window size reaches 0, transmission ...As ACKs are receved, space is freed in t ...UDPUser Datagram ProtocolConnectionlessBest effort deliveryApplicationsBroadcastRouting TablesGamesStreaming audio/videoTime sensitive applicationsICMPInternet Control Message ProtocolConnectionlessUnreliablepingICMP 8 - Echo RequestICMP 0 - Echo ReplyRedirect (ICMP 5)User sends datagram destined for network ...Router R1 knows that network X can be re ...R2 is also directly connected to the hos ...Router R1 sends ICMP redirect to host st ...R1 forwards original datagram to destina ...Host from then on uses R2 to send datagr ...Destination Unreachable (ICMP 3)Routing ProtocolsAutonomous SystemsInterior Gateway ProtocolsRouting Protocols used within ASRIP (Routing Information Protocol)IGRP (Interior Gateway Routing Protocol)OSPF (Open Shortest Path First)Exterior Gateway ProtocolsRouting Protocols used to link AS'sBGP (Border Gateway Protocol)Distance Vector Routing ProtocolsMetric is # hops to destination netRouters frequently propagate routing tab ...Routing tables only passed between direc ...Link State Routing ProtocolsBest route based on a number of factorsLink speedCongestionManual preferenceIf interface changes state, neighbours a ...Routers have knowlege of entire network ...Quality of Service (QoS)ReliabilityAcceptable ratio of packet lossAcceptable error rateDelivery timeReduction of jitterPeak data rateATM (Asyncronous Transfer Mode)Small, fixed length cells (53 bytes)5 byte header48 byte payloadAllows very fast switchingNo need for stop bitsNo frame-size headers to readConnection orientated protocolQoS for time sensitive dataFiber opticTransmission speeds (per physical link)155Mbps Long Distance622Mbps Short distanceHeadersVirtual Path Identifiers (VPI)Virtual Circuit Identifiers (VCI)Generic Flow Control (GFC) - Submultiple ...Payload Type Identifier (PTI)Cell Loss Priority (CLP)Header Error Control (HEC)Each physical link can carry many VPIs1 VPI can carry many VCIsAllows VPIs to be carved up to requireme ...1 VPI could carry voice, data and video ...2 Types of CellUNI (User Network Interface)NNI (Network to Network Interface)NNI Uses General Flow Control (GFC) to i ...ATM Adaption Layers (AAL)AAL1Constant Bitrate (CBR)Connection OrientatedFixed, constant connectionsAAL2Variable Bitrate (VBR)Connection OrientatedAudio and VideoAAL5Variable Bitrate (VBR)Connection OrientatedUsed for dataAAL3/4VariableConnectionlessRarely usedDefined at connection set up, not in hea ...Domain Name System (DNS)Maps IP addresses to friendly namesHierarchialOrganisational (.gov, .mil)Geographical (.fr, .uk)DNS Zone - area for which a DNS server i ...Authoritative NS - A nameserver which ca ...Non-authoritative - A nameserver which h ...Address Resolution Protocol (ARP)Maps an IP address to a MAC addressARP Probe queries who an IP belongs toARP update informs other hosts that the ...ARP frames are broadcast
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Adv. Net
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Internet Protocol (IP)
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IPv6
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2^128 addresses
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First 64bits used as network address
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Second 64bits host address
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No CIDR Subnetting
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Packet size up to 64KB
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No fragmentation - Makes use of Path MTU Discovery (PMTUD)
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Header
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Fixed Header
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Version
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Traffic class
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Flow label (QoS management)
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Payload Length
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Next header
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Specifies next encapsulated header --or--
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Specifies presence of extension headers
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Hop limit
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Source Address
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Destination Address
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Extension Header
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Context-specific headers
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One or more can be included
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Examples
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Routing
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Fragmentation
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Authentication (IPsec)
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Destination options
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IPv4
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2^32 Address
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CIDR subnetting
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Header
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Version
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Header length
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DiffServ (QoS)
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Total Length
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Identification
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Flags
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Reserved, must be 0
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Don't Fragment
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More Fragments
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Fragment offset
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TTL
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Protocol
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Checksum
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Source address
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Destination address
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Fragmentation
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If datagram is larger than MTU then packet is fragmented
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More fragment flag indicates if there are more fragments to come
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Fragment offset indicates how many fragmented bytes have been sent
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Don't fragment flag will make datagrams be dropped if they are too large
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Wireless
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802.11
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Legacy
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2.4GHz band
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1 - 2 Mbps
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FHSS (Frequency Hopping Spread Spectrum)
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DSSS (Direct Sequence Spread Spectrum)
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A
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54Mbps
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5GHz ISM Band
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Short range (30m)
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OFDM
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B
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2.4GHz
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Greater range (90m)
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11Mbps
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Better modulation than 1997
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DSSS/FHSS
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G
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54Mbps
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90m range
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OFDM (with compatibility for B)
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N
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2.4GHz and 5GHz
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Upto 600Mbps (144 achievable)
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Multi In Multi Out (MIMO)
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250m range
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WiMAX
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Worldwide Interoperability for Microwave Access
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IEEE 802.16-2004 fixed infrastructure
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Scalable Orthogonal Frequency Division Multiple Access (SOFDMA)
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802.16e supports mobile devices
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Upto 74Mbps
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Upto 10 miles w/Line of Sight
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5 Miles non Line of Sight
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Zigbee
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Low power
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Wireless mesh
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Operates at 868MHz, 2.4GHz
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Binary Phase Shift Keying (BPSK) at 868MHz
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Quadrature Phase Shift Keying (QPSK) at 2.4GHz
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20Kbps @ 868MHz
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250Kbps @ 2.4GHz
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Range 10 - 75m
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Low latency from sleep
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Incompatible with GPL and many FOSS Licences
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Devices
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ZigBee Co-ordinator (ZC)
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Root of network
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Bridge to other networks
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Only one per network
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Trust Center and Key Repository
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ZigBee Router (ZR)
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Application function
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Acts as a mesh node
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ZigBee End Device (ZED)
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No Routing
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Very little hardware
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Pushes data onto network
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Direct Sequence Spread Spectrum (DSSS)
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Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA)
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Cellular
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Layer 4 Protocols
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TCP
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Connection Orientated
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Transmission Control Protocol
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TCP Handshake
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SYN flag set
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Random SYN number set
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SYN segment transmitted
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Reciever responds with ACK and SYN +1
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Reliable datagram delivery
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Applications
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Web browsing
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Email
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Bursty data
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Data which requires reliability
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Sliding Window Mechanism
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Certain number of bytes are transmitted before requiring an ACK
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Window size negotiated with reciever
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When window size reaches 0, transmission stops
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As ACKs are receved, space is freed in the window
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UDP
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User Datagram Protocol
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Connectionless
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Best effort delivery
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Applications
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Broadcast
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Routing Tables
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Games
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Streaming audio/video
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Time sensitive applications
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ICMP
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Internet Control Message Protocol
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Connectionless
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Unreliable
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ping
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ICMP 8 - Echo Request
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ICMP 0 - Echo Reply
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Redirect (ICMP 5)
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User sends datagram destined for network X via router R1
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Router R1 knows that network X can be reached via a better route R2
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R2 is also directly connected to the host (and R1 knows this)
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Router R1 sends ICMP redirect to host stating the R2 is better
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R1 forwards original datagram to destination
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Host from then on uses R2 to send datagrams to network X
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Destination Unreachable (ICMP 3)
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Routing Protocols
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Autonomous Systems
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Interior Gateway Protocols
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Routing Protocols used within AS
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RIP (Routing Information Protocol)
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IGRP (Interior Gateway Routing Protocol)
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OSPF (Open Shortest Path First)
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Exterior Gateway Protocols
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Routing Protocols used to link AS's
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BGP (Border Gateway Protocol)
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Distance Vector Routing Protocols
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Metric is # hops to destination net
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Routers frequently propagate routing tables to neighbours
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Routing tables only passed between directly connected routers
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Link State Routing Protocols
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Best route based on a number of factors
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Link speed
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Congestion
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Manual preference
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If interface changes state, neighbours are informed
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Routers have knowlege of entire network topography
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Quality of Service (QoS)
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Reliability
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Acceptable ratio of packet loss
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Acceptable error rate
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Delivery time
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Reduction of jitter
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Peak data rate
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ATM (Asyncronous Transfer Mode)
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Small, fixed length cells (53 bytes)
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5 byte header
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48 byte payload
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Allows very fast switching
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No need for stop bits
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No frame-size headers to read
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Connection orientated protocol
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QoS for time sensitive data
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Fiber optic
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Transmission speeds (per physical link)
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155Mbps Long Distance
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622Mbps Short distance
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Headers
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Virtual Path Identifiers (VPI)
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Virtual Circuit Identifiers (VCI)
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Generic Flow Control (GFC) - Submultiplexing
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Payload Type Identifier (PTI)
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Cell Loss Priority (CLP)
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Header Error Control (HEC)
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Each physical link can carry many VPIs
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1 VPI can carry many VCIs
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Allows VPIs to be carved up to requirements
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1 VPI could carry voice, data and video separately
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2 Types of Cell
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UNI (User Network Interface)
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NNI (Network to Network Interface)
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NNI Uses General Flow Control (GFC) to increase VPI address space
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ATM Adaption Layers (AAL)
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AAL1
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Constant Bitrate (CBR)
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Connection Orientated
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Fixed, constant connections
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AAL2
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Variable Bitrate (VBR)
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Connection Orientated
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Audio and Video
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AAL5
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Variable Bitrate (VBR)
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Connection Orientated
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Used for data
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AAL3/4
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Variable
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Connectionless
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Rarely used
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Defined at connection set up, not in header
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Domain Name System (DNS)
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Maps IP addresses to friendly names
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Hierarchial
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Organisational (.gov, .mil)
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Geographical (.fr, .uk)
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DNS Zone - area for which a DNS server is responsibel
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Authoritative NS - A nameserver which can provide definitive information on a name
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Non-authoritative - A nameserver which has cached details of a domain
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Address Resolution Protocol (ARP)
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Maps an IP address to a MAC address
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ARP Probe queries who an IP belongs to
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ARP update informs other hosts that the IP has changed for a MAC
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ARP frames are broadcast