Bài giảng Mạng máy tính nâng cao - Chương 1: Overview

1Chapter 01: OverviewMẠNG MÁY TÍNH NÂNG CAO2Data networks developed as a result of business applications that were written for microcomputers. Businesses needed a solution that would successfully address the following three problems: How to avoid duplication of equipment and resources How to communicate efficiently How to set up and manage a network Data networks 3Network topology4Logical TopologiesBroadcastToken Passing5Local-area networks (LANs)6Local-area networks (LANs)LANs consist of the following components: Computers Network interface cards Peripheral devices Networking media Network devices Some common LAN technologies are: Ethernet Token Ring FDDI 7Wide-area networks (WANs)8Wide-area networks (WANs)WANs interconnect LANs, which then provide access to computers or file servers in other locations. Some common WAN technologies are: Modems Integrated Services Digital Network (ISDN) Digital Subscriber Line (DSL) Frame Relay US (T) and Europe (E) Carrier Series – T1, E1, T3, E3 Synchronous Optical Network (SONET)9OSI layersDividing the network into seven layers provides the following advantages: It breaks network communication into smaller, more manageable parts. It standardizes network components to allow multiple vendor development and support. It allows different types of network hardware and software to communicate with each other. It prevents changes in one layer from affecting other layers. It divides network communication into smaller parts to make learning it easier to understand.10TCP/IP model11TCP/IP model12Ethernet and the OSI model13Ethernet and the OSI model14Ethernet Naming – MAC address15Ethernet frame fieldsStart Frame Delimiter : 1010101116Encapsulating Data17De - encapsulating Data18Switches and BridgesData LinkOR123124Each segment has its own collision domainAll segments are in the same broadcast domainBroadcasts are forwarded to all segments19Ethernet Switching20Network Device Domains21Interconnecting Networks with TCP/IP22Introduction to TCP/IPHostInternetTCP/IPHostEarly protocol suiteUniversal23OSI Model and TCP/IP Protocol Model 24Application Layer Overview25Transport Layer Overview26Transport Layer FunctionsNetworkIPXIPTransportSPXTCPUDPDistinguishes between upper layer applicationsEstablishes end-to-end connectivity between applicationsDefines flow control Provides reliable or unreliable services for data transfer27Reliable Transport Layer FunctionsSynchronizeAcknowledge, SynchronizeAcknowledgeData Transfer(Send Segments)SenderReceiverConnection Established28TCP Segment Format20 bytes29Port Numbers30TCP Port Numbers31TCP Three Way Handshake32TCP Three Way Handshake33TCP Three Way Handshake34Denial-of-Service AttacksDenial-of-service (DoS) attacks are designed to deny services to legitimate hosts attempting to establish connections. In a DoS attack, the hacker initiates a synchronization but the receiving device replies to a non-existent, unreachable IP address and then is placed in a wait-state while waiting to receive the final ACK from the initiator. 35TCP Simple Acknowledgment36TCP Simple Acknowledgment37TCP Simple Acknowledgment38TCP Simple Acknowledgment39TCP Simple Acknowledgment40TCP Simple Acknowledgment41TCP Sequence and Acknowledgment Numbers42TCP Sequence and Acknowledgment Numbers43TCP Sequence and Acknowledgment Numbers44TCP Basic Windowing45TCP Sliding Windowing46TCP Sliding Windowing47UDP Segment Format48Network Layer FunctionsDefines logical source and destination addresses associated with a specific protocolDefines paths through networkInterconnects multiple data links49Network Layer Functions50Network Layer Functions51Internet Layer OverviewOSI network layer corresponds to the TCP/IP internet layerInternet Protocol (IP)Internet Control MessageProtocol (ICMP)Address ResolutionProtocol (ARP)Reverse AddressResolution Protocol (RARP)ApplicationTransportInternetData LinkPhysical52IP Datagram53Protocol FieldTransportLayerInternetLayerTCPUDPProtocolNumbersIP17654Internet Control Message ProtocolApplicationTransportInternetData LinkPhysicalDestination UnreachableEcho (Ping)OtherICMP155Address Resolution Protocol56Address Resolution Protocol57Address Resolution Protocol58Address Resolution Protocol59Reverse ARP60Reverse ARP61Reverse ARP62Reverse ARP63Introduction to TCP/IP AddressesUnique addressing allows communication between end stationsPath choice is based on destination address64IP Addressing65IP Address Classes66IP Address Classes67Host Addresses68Determining Available Host Addresses69Addressing without Subnets70Addressing with Subnets71Subnet Addressing72Subnet Addressing73Subnet Mask74Decimal Equivalents of Bit Patterns75Subnet Mask without Subnets76Subnet Mask with Subnets77Subnet Mask with Subnets78Broadcast Addresses