Exploring the Packet Delivery Process英文版).ppt

BuildingaSimpleNetwork ExploringthePacketDeliveryProcess Layer1Devices Layer1providesthephysicalmediaanditsencoding Examples EthernetSerialRepeaterPhysicalinterfaceoftheNIC Layer2Devices Layer2devicesprovideaninterfacewiththephysicalmedia Examples NICBridgeSwitch Layer2Addressing MACaddressAssignedtoenddevices Layer3DevicesandTheirFunction Thenetworklayerprovidesconnectivityandpathselectionbetweentwohostsystems Inthehost thisisthepathbetweenthedatalinklayerandtheupperlayersoftheNOS Intherouter itistheactualpathacrossthenetwork Layer3Addressing EachNOShasitsownLayer3addressformat OSIusesanNSAP TCP IPusesIP ARP ARPTable Host to HostPacketDelivery 1of22 Host to HostPacketDelivery 2of22 Host to HostPacketDelivery 3of22 Host to HostPacketDelivery 4of22 Host to HostPacketDelivery 5of22 Host to HostPacketDelivery 6of22 Host to HostPacketDelivery 7of22 Host to HostPacketDelivery 8of22 Host to HostPacketDelivery 9of22 Host to HostPacketDelivery 10of22 Host to HostPacketDelivery 11of22 Host to HostPacketDelivery 12of22 Host to HostPacketDelivery 13of22 Host to HostPacketDelivery 14of22 Host to HostPacketDelivery 15of22 Host to HostPacketDelivery 16of22 Host to HostPacketDelivery 17of22 Host to HostPacketDelivery 18of22 Host to HostPacketDelivery 19of22 Host to HostPacketDelivery 20of22 Host to HostPacketDelivery 21of22 Host to HostPacketDelivery 22of22 DefaultGateway Host BasedTools ping Host BasedTools Table Host BasedTools tracert Summary Layer1providesthephysicalmediaanditsencoding Layer2devicesprovideaninterfacewiththephysicalmedia Layer2addressesareMACaddresses Thenetworklayerprovidesconnectivityandpathselectionbetweentwohostsystems Layer3addressesareIPaddresses Summary Cont Beforeahostcansenddatatoanotherhost itmusthavetheMACaddressofthathost IftheMACaddressisnotknown ARPisusedtomapLayer2toLayer3 ReliablecommunicationrequiresaTCPsession Datasentmustbeacknowledged Ifhostsareondifferentsegments ade