第 五 章
description
Transcript of 第 五 章
-
Internet
-
1
-
datagram
-
H1AH2H2
-
virtual circuit
-
2 InternetThe Internet is an interconnected collection of many networks.
-
internetworkinginternetworkinternet
-
internet layerTCP/IPTCPIPTCP/IPIPInternet ProtocolICMP
-
2.1 IPbest-efforts IPIPv4IPv6
-
1 IPv4
-
IPIPIP
-
2IPIPIPIPv432IP11000001 00100000 11011000 00001001 193.32.216.9IP
-
IPIPABC
-
IPIPICANNABC
-
IP01 013213200127.xx.yy.xx
-
ABCA224-2 = 16777214B216-2 = 65534C28-2 = 254ABCA27-2 = 126B214-2 = 16382C221-2 = 2097152ABCA1.0.0.0~126.255.255.255B128.1.0.0~C
-
3subnet
-
IP
-
+
-
subnet mask +320255.255.255.0+IP 128.10.1.1 AND 255.255.255.0 = 128.10.1.0
-
4 IPdirect deliveryindirect delivery
-
IP
-
Cloud
Mac II
202.38.64.0
Q
A
20.0.0.0
R
30.0.0.0
S
40.0.0.0
202.38.64.1
20.0.0.5
20.0.0.6
30.0.0.6
30.0.0.7
40.0.0.7
20.0.0.0
30.0.0.0
202.38.64.0
255.0.0.0
255.0.0.0
255.255.255.0
40.0.0.0
255.0.0.0
R
A
0
20.0.0.5
30.0.0.7
0
1
0
1
0
1
202.38.64.0
default
255.255.255.0
0.0.0.0
202.38.64.1
0
0
-
IPIP D N if DIP then protocol else if N then D else if D then else if N then else if then else
-
5CIDRCIDRaggregate
-
200020482121CIDRL232-log2L194.24.0.0 255.255.248.0/194.24.0.0/21
-
CIDRISP194.24.0.0 20481140961210241010
-
194.24.0.0/2111111111 11111111 11111000 00000000194.24.8.0/22 11111111 11111111 11111100 00000000 194.24.16.0/20 11111111 11111111 11110000 00000000 194.24.17.4194.24.17.4 AND 255.255.248.0 = 194.24.16.0194.24.17.4 AND 255.255.252.0 = 194.24.16.0194.24.17.4 AND 255.255.240.0 = 194.24.16.0
-
ISP16192.4.16.0~192.4.31.016C16192.4.16.0/2016
-
RFC 1519IPv443200194.0.0.0195.255.255.255198.0.0.0199.255.255.255200.0.0.0201.255.255.255202.0.0.0203.255.255.255
-
IPIPCIDR
-
CIDRIP192.4.23.0 192.4.16.0/20192.4.23.0/24
-
6MTUMTU1500MTU576MTUMTUIPIPMTUfragmentation
-
138HNN H + N MTU N 8
-
HMTUNNN H + NMF01 /8
-
4000IPMTU1500IP20 N 1480148014801020
-
MTU
-
IPMF=0
-
IP
-
2.2 IP
-
ARPIPABIP IBIBBIP
-
ARP/RARP1IP0800166IP4ARP1ARP2RARP3RARP4ARP080616
-
ABIPMACAARPMACIPBIPAARPARPIPIPBARPMAC2BARPAMAC
-
ARPARPARPARPARPARPARPARP15
-
ARPARPARPARPAARPIPARPAARPAARP
-
ARPIPARPARP1ARPIPIPARP
-
Three interconnected /24 networks: two Ethernets and an FDDI ring.Three interconnected /24 networks: two Ethernets and an FDDI ring.
-
2.3 ICMPICMPICMPICMPIPIPICMPICMPICMPIP
-
ICMPICMPTTL0ICMP//
-
ICMPtype15codeChecksumICMP
-
ICMPpingPingICMP Type=8Code=0 Echo Request Type=0Code=0 Echo ResponseEcho Response
Process
type(0 or 8)
code(0)
checksum
optional data
0
7
8
15
16
31
5-27 ICMP
sequence number
identifier
8 bytes
-
ICMPTracerouteTracerouteTracerouteType=8Code=0Echo RequestIPTTL1TTL1TTL0ICMPTracerouteIPType=8Code=0Echo RequestIPTTL2 IPTTL3ICMPType=0Code=0Echo Response
-
3
-
3.1 Distance Vector
Connect
Process
Text
B
B
B
B
B
B
2
1
3
1
2
5
6
1
5-4
-
DVBellman-FordBellman-Fordxy N(x)xc(x,p)xpN(x)xydx(y)dx(y) = minp{c(x,p) + dp(y)}pN(x)p xyBellman-FordDVBellman-Ford
-
DVBellman-Ford
-
DV(a) A subnet. (b) Input from A, I, H, K, and the new routing table for J.
-
Route Information ProtocolRIPRIP303016RIP16RIPRIPRIPUDP
-
3.2 Link State
-
HELLOECHO2
-
32
-
LS
-
Dijkstra
-
Open Shortest Path FirstOSPFOSPFOSPFOSPFRIPOSPFIP89
-
3.3 ASarea
-
3.4 N-Way-Unicast
-
1
-
(a) A subnet. (b) a Sink tree. (c) The tree built by reverse path forwarding.
-
3.5
-
(a) A network. (b) A spanning tree for the leftmost router. (c) A multicast tree for group 1. (d) A multicast tree for group 2.
-
DVMRPpruneGGSG
-
4
-
-CPU
-
CPU
-
1admission controltraffic shapingtraffic policing
-
2warning bit
-
3choke packetshop-by-hop choke packets
-
4Ramdom Early Detection, RED p AvgLen = (1- Weight)AvgLen + WeightSampleLen p TCP
-
5
-
(a) Two Ethernets connected by a switch. (b) Two Ethernets connected by routers.
-
5.1
-
IPDst IP addr = H2Src IP addr = H1Dst MAC addr = M1Src MAC addr= H1IPDst IP addr= H2Src IP addr = H1Dst addr = M2Src addr = M1IPDst IP addr = H2Src IP addr = H1Dst MAC addr = H2Src MAC addr= M2
-
MBoneoverlay networkMBone
-
MBone
Direct access storage
Process
Dst addr =
Dst addr =
IP
IP
Dst IP addr = M2
Src IP addr = M1
Dst addr =
M2
M1
C
D
IP
-
5.2
-
Autonomous SystemASASASICANNASASAS
-
routing metricInternet
-
InternetIGPASOSPFRIPEGPASBGP
-
ASASASAS
-
BGPASASASBGP speakerBGPBGPASASBGPtransitASstubAS
-
ASAS2BGP speaker128.96, 192.4.153, 192.4.32, 192.4.3AS2AS1BGP speaker128.96, 192.4.153, 192.4.32, 192.4.3
QAS5
A AS2
B (AS3)
P(AS4)
AS1
RAS6
SAS7
128.96192.4.153
192.4.32192.4.3
192.12.69
192.4.54192.4.23
5-10
-
routing arbiterBGPAS
-
6 IPIPmigratoryroamingIPIPIP
-
home networkhome addressforeign networkcare-of addresshome agentforeign agent
-
IPARPARPMACARPARPARP
-
:MAC
-
7 IPv6IPv6...IPv6IPv4
-
IPv6128168000:0:0:0:123:4567:89AB:CDEF08000::123:4567:89AB:CDEFIPv6IPv6anycast
-
IPv6IPv640IPv4IPv6IHLIPv640Next headerIPv6
-
IPv6IPv4
-
IPv4IPv6IPv4IPv6
-
8 CPUCPU
-
IP
-
IPCPUI/OCPUCPUCPUCPU
-
I/O
-
IPCPUCPUCPUCPUCPU
-
IP
DMA
MAC
CPU
DMA
MAC
CPU
DMA
MAC
CPU
CPU
5-30
-
IPMGRMulti-gigabit routerCPUcrossbarCPUCrossbar
-
CPU
5-31
-
MGR
-
IPIPIPIP/CIDRARP
-
914333438394043
134142
1 2