middleware pour software radio€¦ · computer networks network layer & ip protocol...
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P.Bakowski 1
Computer NetworksComputer Networks Network Layer & IP protocolNetwork Layer & IP protocol
bako@ieee.orgbako@ieee.org
www.smartcomputerlab.orgwww.smartcomputerlab.org
P.Bakowski 2
digital digital communicationcommunication
Functional LayersFunctional Layers
Network layerNetwork layer
Transport layerTransport layer
Application layerApplication layer
Physic layerPhysic layerMAC layerMAC layerLink layerLink layer
datadata : text, audio, video,.. : text, audio, video,..
segmentssegments , , datagramsdatagrams
packetspackets
framesframes
bitsbits
signalssignals
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Network Layer & Internet InfrastructureNetwork Layer & Internet Infrastructure
long links & many routers long links & many routers => => transmission & routing errorstransmission & routing errors
TransportTransport
ApplicationApplication
Network layerNetwork layerNetworkNetwork
TransportTransport
ApplicationApplication
Network layerNetwork layerNetworkNetwork
NetworkNetwork NetworkNetwork NetworkNetwork
routerrouterrouterrouter routerrouter routerrouter
routerrouterrouterrouter
corruption of bits corruption of bits loss of packetsloss of packets
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Network Layer & Internet InfrastructureNetwork Layer & Internet Infrastructure
IP packets and @IP are analyzed by routersIP packets and @IP are analyzed by routers
Transport Transport
Application Application
Network Network
routerrouter
Network Network
routerrouter
LANLANLANLAN switchswitchswitchswitch
Network layerNetwork layerrouterrouter
IP packetIP packet
LAN LAN
ETHETH
Locally the IP packets are carried by Ethernet/WiFi framesLocally the IP packets are carried by Ethernet/WiFi frames
Network Network
IP packetIP packet
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IP addressing scheme (v4)IP addressing scheme (v4)The Internet addressing scheme is two-level scheme :The Internet addressing scheme is two-level scheme :• network levelnetwork level (network address or number) (network address or number) • host level host level (host address or number) (host address or number)
hosthost
routerrouter
switchswitch
switchswitch
routerrouter
networknetwork
routerrouter
32-bit32-bit
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IP addressing scheme (v4)IP addressing scheme (v4)There are two kinds of addressing schemes :There are two kinds of addressing schemes :based on based on classes classes : A,B,C,D: A,B,C,D
AA 0...0... 0 – 127...0 – 127...
/11/11
0 (20 (221211)1) 0 (20 (211111)1)
172.19.64.141172.19.64.141
based on based on prefixprefix (class-less) (class-less)
128 – 191...128 – 191...10..10..BB192 – 223...192 – 223...110110110.110.CC
1110.1110. 224 – 239...224 – 239... multicastmulticast
DD
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IP addressing scheme (v4)IP addressing scheme (v4)
switchswitch
switchswitch
32-bit32-bit
201.123.34.201.123.34.xxxxxx
201.123.34.201.123.34.1010 unicastunicast
routerrouterrouterrouter routerrouter
all computers on this network are all computers on this network are « visible »« visible »
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IP addressing scheme (v4)IP addressing scheme (v4)
routerrouter
switchswitch
switchswitch
routerrouter routerrouter
32-bit32-bit
201.123.34.201.123.34.xxxxxx
201.123.34.201.123.34.255255 broadcastbroadcast
all computers on this network are all computers on this network are « visible »« visible »
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IP addressing scheme (v4)IP addressing scheme (v4)
switchswitch
switchswitch
32-bit32-bit
231.123.34.15231.123.34.15
joinjoin and and leaveleave
routerrouterrouterrouter routerrouter
231.123.34.15231.123.34.15 multicastmulticast
201.123.34.201.123.34.1010201.123.34.201.123.34.1212201.123.34.201.123.34.2121201.123.34.201.123.34.3232
201.123.34.201.123.34.1010 201.123.34.201.123.34.1212
201.123.34.201.123.34.2121201.123.34.201.123.34.3232
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IP packetsIP packets
IHLIHL – header length – header length (in 32-bit words)(in 32-bit words)
TOSTOS – Type of Service (6-bit field) – Type of Service (6-bit field)
Total LengthTotal Length of IP of IP packetpacket or or fragmentfragment in bytes in bytes
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IP packetsIP packets
IdentifierIdentifier – a unique – a unique value for IP packet and value for IP packet and all its fragmentsall its fragments
IP FlagsIP Flags : : D – Don't fragmentD – Don't fragmentM – More fragmentsM – More fragments
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IP packetsIP packets
TTLTTL – the maximal – the maximal number of routing number of routing hopshops
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IP fragmentationIP fragmentation
IP fragIP fragETHETH IP fragIP fragETHETH IP fragIP fragETHETH IP fragIP fragETHETH
13-bit ?13-bit ?
The same identifier !The same identifier !
IP packetIP packet
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IP fragmentation – an exampleIP fragmentation – an example
IP fragIP frag
20+? 20+?
ETHETH
IP packet: 20 header bytes + 5000 data bytes IP packet: 20 header bytes + 5000 data bytes + +
MTU for Ethernet is 1500 bytesMTU for Ethernet is 1500 bytes
IP fragIP fragETHETH
20+1480 20+1480
IP fragIP fragETHETH
20+1480 20+1480
IP fragIP fragETHETH
20+1480 20+1480
13-bit13-bit
TL=1500,FO=0TL=1500,FO=0 TL=1500,FO=185TL=1500,FO=185 TL=1500,FO=370TL=1500,FO=370 TL=?,FO=?,M=?TL=?,FO=?,M=?
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How to get IP addressHow to get IP addressThere are There are two waystwo ways to get an IP address : to get an IP address :● The The manualmanual (fixed) – the user/administrator (fixed) – the user/administrator fixes the addresses fixes the addresses ● The The automaticautomatic (dynamic)- the directly visible (dynamic)- the directly visible router provides the IP address + the IP address router provides the IP address + the IP address of the router/gateway + the address of the DNS of the router/gateway + the address of the DNS serverserverff:ff:ff:ff:ff:ffff:ff:ff:ff:ff:ff broadcastbroadcast
routerrouterCLICLI
ETHETH IPHIPH UDP:67UDP:67
replyreply
ETHETH IPHIPH UDP:67UDP:67
requestrequest
6767
DDynamic ynamic HHost ost CControl ontrol PProtocolrotocol
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How to get physical addressHow to get physical address
ff:ff:ff:ff:ff:ffff:ff:ff:ff:ff:ff 172.19.64.140172.19.64.140
To communicate between computers we need to use To communicate between computers we need to use physical addressesphysical addresses. . Before sending an IP packet we must acquire the physical Before sending an IP packet we must acquire the physical (MAC) destination address via (MAC) destination address via Address Request ProtocolAddress Request Protocol – – ARPARP ! !
SRCSRC DSTDST
ETHETH IPHIPH ARP:requestARP:request
ETHETH IPHIPH ARP:replyARP:reply 172.19.64.140172.19.64.140
Cache ARPCache ARP
@IP @IP @ETH @ETH @IP @IP @ETH @ETH @IP @IP @ETH @ETH @IP @IP @ETH @ETH
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internetinternetinternetinternet
routerrouter
routerrouter
BGP protocolBGP protocol
Routing protocols (tables)Routing protocols (tables)
ASASASASRR
routerrouterRRRR RR
router/gatewayrouter/gateway
ASASASAS
routerrouter
RR
RR
CC
TT TT TT TTAutonomous SystemAutonomous System
Free/OrangeFree/Orange
LANLANLANLAN SSRR
TT TT TT
RR
RIP protocolRIP protocol
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The Implementation : IP layerThe Implementation : IP layer
OS OS kernelkernel
UDP/TCPUDP/TCPIP/ICMP/RIPIP/ICMP/RIPARPARP/RARP/RARP
« socket » interface« socket » interface
Ethernet/WiFi interfaceEthernet/WiFi interface
Network layerNetwork layer
Transport layerTransport layer
Application layerApplication layer
Physic layerPhysic layerMAC layerMAC layerLink layerLink layer
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SummarySummary
Internet (Internet (networknetwork) layer architecture) layer architecture IP addressingIP addressing with classes & class-less with classes & class-less IPIP packets packets headerheader and functions and functions IP fragmentationIP fragmentation How to get How to get IP addressIP address How to learn How to learn physical addressphysical address – MAC address – MAC address Routing IP packetsRouting IP packets over Internet over Internet
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Complementary lecturesComplementary lectures
4.1. Network Layer Overview4.1. Network Layer Overview4.2. Network Services4.2. Network Services4.3. Internetworking4.3. Internetworking4.4. IP Prefixes4.4. IP Prefixes4.5. IP Forwarding4.5. IP Forwarding4.6. IP helpers: ARP and DHCP4.6. IP helpers: ARP and DHCP4.7. IP Packet Fragmentation4.7. IP Packet Fragmentation4.8. IP Errors and ICMP4.8. IP Errors and ICMP4.10 Network Address Translation (NAT)4.10 Network Address Translation (NAT)
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