thuc tap tong quan ve ipv6 yjpdevqvzm 20130322112350 4

7/30/2019 Thuc Tap Tong Quan Ve Ipv6 YjpDEvqVzM 20130322112350 4

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Mc lc 1Danh mc cc ch vit tt 3Danh mc cc t kho 4

Danh mc cc bng v hnh v 6Li ni u 8

Chng 1 : Cc vn ca a ch IPv41. a ch IPv42. Cc vn ca IPv43. Cc u im m IPv6 cung cp

91016

Chng 2 : Tng quan v a ch IPv6

1. Cu trc v cc loi a ch IPv61.1.Cu trc1.2.Cp pht a ch IPv61.3.Cc loi a ch IPv6

1.1.1. a ch unicast1.1.2. a ch Anycast211.1.3. a ch Multicast1.1.4. Cc dng a ch IPv6 khc

2. Cu trc trng header ca gi tin IPv62.1.Cu trc Header ca gi tin IPv62.2.Extension header

3. ICMPv63.1.Cu trc3.2.Mt s loi bn tin ICMP3.3.Qu trnh phn mnh v xc nh MTU

4. Neighbour discoverry4.1.Cc bn tin ICMP s dng trong neighbour discovery4.2.Bn tin Router Solicitation4.3.Mt s chc nng m ND cung cp

5. Autoconfiguration5.1.Stateful v Stateless autoconfiguration5.2.Router v network renumbering

6. nh tuyn trong IPv66.1.Distance vector

1717171919212122

23232526262729313131313232353535

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6.2.Link state6.3.RIP v RIPng6.4. OSPF v OSPFn

7. Security trong IPv6

7.1.Cc mode hot ng7.2.Hot ng

353636394040

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Danh mc cc ch vit tt

ID : Indentify DigitIP : Internet Protocol

VLSM : Variable Length Subnet MaskCIDR: Classless Inter-Domain RoutingNAT : Network Address TranslationPAT : Port Address TranslationRFC : Request For Commentaddr : addressTLA : Top Level AggregationNLA : Next Level AggregationSLA : Site Level AggregationRES : ReversedTTL : Time To LiveECN : Explicit Congestion NotificationICMP : Internet Control Message ProtocolMTU : Maximum Transmission UnitPMTU : Path Maximum Transmission Unitadv : advertismentDHCP : Dynamic Host Configuration ProtocolREQ : RequestCONFL : ConfilctINFO-REQ : Information RequestRELAY-FORW : Relay Forward

DNS : Domain Name ServerLSA : Link State AdvertismentRIP : Routing Information ProtocolOSPF : Open Shortest Path FirstDBD : Database Descryption PacketLSR: LinkState RequestLSU : LinkState UpdateLSACK: LinkState AcknowledgeDR: Designated RouterBDR: Backup Designated Router

AH : Authentication HeaderESP : Encapsulating Security PayloadND : Neighbour discovery

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Danh mc cc t kho

Variable Length Subnet Mask: l phng php chia nh 1 a ch mng lnthnh cc mng nh hn c subnet mask khc nhau

Classless Inter-Domain Routing : l phng php gp cc a ch mng nhthnh 1 a ch mng ln duy nht.Request For Comment : l phng thc xy dng cc chun m ca IETF.Trong , bt c ai cng c th ng gp xy dng nn mt chun hon chnhPort Address Translation : l phng thc chuyn i c a ch IP v port do cng mt lc c th cung cp nhiu phin NAT ra ngoi InternetTop Level Aggregation : l nh cung cp cp cao nht. Cc nh cung cp thphn mun c cp a ch IP cn phi ng k vi nh cung cp ny. khu vcBc M l NIC (Network Information Center), khu vc Chu u l NCC(Network Coodirnoction Center), Chu -Thi Bnh Dng l APINC.Next Level Aggregation : l cc nh cung cp cp tip theo. VD nh cc ISP(FPT, VDC, )Site Level Aggregation : cc t chc, s dng Internet, s c th c nhiu sitekhc nhau, mi site s c 1 gi tr Site Level Aggregation ID khc nhau nhdanh cho 1 siteTime To Live : mt gi tin khi i trong mng s c gn 1 gi tr TTL. Milnqua 1 Router n s gim gi tr trng ny i 1. Nu TTL = 0, gi tin s b hu.Explicit Congestion Notification : trng thng bo tc nghnInternet Control Message Protocol : giao thc s dng tng 3 dng phthin li khi gi gi tinMaximum Transmission Unit : dung lng ti a ca gi tin khi truyn trong

mngDynamic Host Configuration Protocol : giao thc dng cu hnh t ng choc host khi n mi kt ni vo mngDomain Name Server : server ng vai tr dch t tn min sang a ch IP hocngc liLink State Advertisment : bn tin qung b dng trong cc giao thc nh tuynLink State, cc Router s dng thng tin thu thp t LSA xy dng vv updatebng nh tuynNode : tt c cc thit b chy v s dng IPv6. Bao gm c Router v hostRouter : l mt node c kh nng chuyn tip cc gi tin IPv6 c a ch ch ko

phi l a ch ca n.Host : l 1 nde ko c kh nng chun tip cc gi tin IPv6 c a ch ch ko phil n.Link: bao gm mt hoc nhiu mng con cng ni vo 1 interface ca Router.Authentication header : l header m rng cung cp cc phogn thc xc thc vbo mt d liu cho gi tin IPv6.

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Extension Header : l phn header nm gia header ca IPv6 v header ca cctng trn, cung cp cho IPv6 mt s chc nng mi.Fragmentation : l qu trnh chia nh ph ni dung ca git in IPv6 c thchin bi node gi nhm tho mn kch thc ti cho php ca 1 link.Neighbour discovery : l qu trnh xc nh cc mi quan h v thu thp thng tin

gia cc node l hng xm vi nhau.Network prefix : l phn u, c nh ca a ch IPv6 dng xc nh a chmng ca 1 a ch IPv6.

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Danh mc cc bng v hnh v

Chng 1 : Cc vn ca a ch IPv4Bng 1.1 : Cc lp a ch IPv4 9Bng 1.2 : a ch IP private

10Hnh 1.1 : a ch IPv4 9Hnh 1.2 : VD v a ch broadcast ca 1 mng 1

0Hnh 1.3 : VD v s dng CIDR 1

3Hnh 1.4 : VD v NAT 1

3Hnh 1.5 : Hot ng ca PAT 1

4Chng 2 : Tng quan v a ch IPv6Bng 2.1 : Cp pht a ch IPv6 1

7Bng 2.2 : Trng ID scope 2

2Bng 2.3 : So snh header ca IPv4 v Ipv6 2

4Bng 2.4 : Cc gi tr ca trng Next header 2

5Hnh 2.1 : So snh ko gian a ch IPv4 v IPv6 1

7Hnh 2.2 : 1 s VD vit a ch IPv6 1

7Hnh 2.3 : Cu trc a ch Global unicast 1

9Hnh 2.4 : cu trc phn cp ca a ch unicast 2

0Hnh 2.5 : Cu trc a ch site local 2

0Hnh 2.6 : Gn a ch link local 2

0Hnh 2.7 : Cu trc a ch link local 2

0Hnh 2.8 : gn ia ch trong 1 link 2

1Hnh 2.9 : cu trc a ch anycast dng gn cho 1 subnet 2

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Hnh 2.10 : cu trc a ch multicast 21

Hnh 2.11 : Cu trc a ch IPv4 trong IPv6 22

Hnh 2.12 : Cu trc gi tin IPv6 2

4Hnh 2.13 : So snh header ca gi tin IPv4 v IPv6 2

4Hnh 2.14 : cu trc gi tin IPv6 v trng extension header 2

5Hnh 2.15 : Cu trc bn tin ICMP 2

6Hnh 2.16 : cu trc bn tin ICMP des unrechable 2

7Hnh 2.17 : Cu trc bn tin ICMP packet too big 2

8Hnh 2.18 : Cu trc bn tin ICMP time exceeded 28

Hnh 2.19 : Cu trc bn tin ICMP parameter problem 29

Hnh 2.20: Echo Request 29

Hnh 2.21 : Echo reply 29

Hnh 2.22 : Path MTU discovery 3

0Hnh 2.23 : Cu trc bn tin Router Solicitation 31

Hnh 2.24 : Hot ng ca RIP 36

Hnh 2.25 : S chuyn trng thi v trao i cc gi tin gia 2 interface OSPF 37

Hnh 2.26 : hot ng ca DR v BDR 38

Hnh 2.27 : S chuyn trng thi ca 1 interface OSPF 39

Hnh 2.28 : Cu trc AH 41

Hnh 2.29 : Cu trc ESP 41

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L ni u

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a chi IPv6 c nhm chuyn trch v k thut ca IETF (InternetEngineering Task Force) ca hip hi Internet xut thuc hin trnc c s ktha cu trc v t chc ca IPv4.

IPv4 c 32 bits a ch vi kh nng l thuyt c th cung cp 1 khng giana ch 32

2=4.294.967.296 a ch. Cn IPv6 vi 128 bits a ch, di gp 4 ln

IPv4, c kh nng cung cp 1 khng gian a ch gp 962 ln. S a ch ny nuri u trn b mt qu t th mi mt vung c khong 656.570 t t a ch.y l mt khng gian a ch cc ln vi mc ch ko ch cho Internet m cncho tt c cc mng my tnh, h thng vin thng, h thng iu khin v thmch cho tng vt dng gia nh.

Vi tc pht trin hin nay, ko gian a ch IPv4 cn kit. Vn chuyn i sang IPv6 l tt yu trong tng li. Vic nm bt trc cc k thuttruyn i v thc hin cc dch v trn nn IPv6 l vn ht sc cn thit.Trong qu trnh thc tp em tin hnh nghin cu v cc vn kh khn ca

IP v4 hin nay v l thuyt tng quan v IPv6.

Chng 1 : Cc vn ca a ch IPv4

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1. a ch IPv4a ch IP ang c s dng hin ti(IPv4) c 32 bit chia thnh 4 Octet (mi

Octet c 8 bit, tng ng 1 byte) cch m u t tri qua phi bt 1 cho n bt32, cc Octet tch bit nhau bng du chm (.), bao gm c 3 thnh phn chnh.

a ch ca mng ( Net ID ) a ch ca my ( Host ID ).a ch Internet c th biu hin dng bit nh phn:

Hnh 1.1 : a ch IPv4

Cc lp a ch IP

Bng 1.1 : Cc lp a ch IPv4a ch cho host v a ch mng

Ta thc hin php AND a ch IP v Subnet mask ta c a ch mngVD : host A c a ch IP 10.34.23.134 v subnet mask 255.0.0.0

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Nh vy host A thuc mng c a ch 10.0.0.0Khi tt c cc host bit l 1 ta c a ch broadcast.

Hnh 1.2 : VD v a ch broadcast ca 1 mnga ch public v private : khi 1 my c kt ni vo mng public n c

gn cho 1 a ch IP v a ch ny ko c trng vi bt c my no trong mng.a ch IP public ny c ng k qua ISP. Vi s pht trin nh hin nay camng Internet th a ch IP public ang trn cn kit. Mt trong nhng phngphp gii quyt vn trn l s dng a ch private. C 3 di a chprivate l :

Bng 1.2 : a ch IP private

2. Cc vn ca IPv42.1.Khng gian a chDo IPv4 ch dng 32 bits nh a ch nn ko gian a ch IPv4 ch c 322

a ch. Vi s pht trin mnh m ca Internet hin nay, ti nguyn a ch IPv4

gn cn kit. gii quyt vn thiu ht a ch IP, ngi ta s dng rt nhiuphng php nh: Subneting, VLSM, CIDR, NAT.

2.1.1. SubnettingHy xt n mt a ch IP class B, 139.12.0.0, vi subnet mask l

255.255.0.0 (c th vit l: 139.12.0.0/16, y s 16 c ngha l 16 bits c

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dng cho NetworkID). Mt Network vi a ch th ny c th cha 65,534 nodeshay computers . y l mt con s qu ln, trn mng s c y broadcast traffic.

Ga s chng ta chia mng ny ra lm bn Subnet. Cng vic s bao gm babc:

Xc nh Subnet mask mi Lit k ID ca cc Subnet mi Cho bit IP address range ca cc HostID trong mi Subnet

Bc 1: Xc nh Subnet mask mi m cho n 4 trong h thng nh phn (cho 4 Subnet) ta cn 2 bits.Do ci Subnet mask s cn 16 (bits trc y) +2 (bits mi) = 18 bitsa ch IP mi s l 139.12.0.0/18 ( con s 18 thay v 16 nh trc y). Cons hosts ti a c trong mi Subnet s l: ((2^14) 2) = 16,382. V tng s cchosts trong 4 Subnets l: 16382 * 4 = 65,528 hosts.

Bc 2: Lit k ID ca cc Subnet miTrong a ch IP mi (139.12.0.0/18) con s 18 ni n vic ta dng 18 bits, mt bn tri, ca 32 bit IP address biu din a ch IP ca mt Subnet.Subnet mask trong dng nh phn Subnet mask11111111 11111111 11000000 00000000 255.255.192.0Nh th NetworkID ca bn Subnets mi c l:Subnet Subnet ID trong dng nh phn Subnet ID1 10001011.00001100.00000000.0000000

0139.12.0.0/18

2 10001011.00001100.01000000.00000000

139.12.64.0/18

3 10001011.00001100.10000000.00000000

139.12.128.0/18

4 10001011.00001100.11000000.00000000

139.12.192.0/18

Bc 3: Cho bit IP address range ca cc HostID trong mi SubnetV Subnet ID dng ht 18 bits nn s bits cn li (32-18= 14) c dng choHostID.Nh ci lut dng cho Host ID l tt c mi bits khng th u l 0 hay 1Subnet HostID IP address trong dng nh

phn

HostID IP address Range

1 10001011.00001100.00000000.0000000110001011.00001100.00111111.11111110

139.12.0.1/18-139.12.63.254/18

2 10001011.00001100.01000000.00000001

139.12.64.1/18-139.12.127.254/18

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10001011.00001100.01111111.11111110

3 10001011.00001100.10000000.0000000110001011.00001100.10111111.1111111

0

139.12.128.1/18-139.12.191.254/18

4 10001011.00001100.11000000.0000000110001011.00001100.11111111.11111110

139.12.192.0/18 139.12.255.254

2.1.2. Variable Length Subnet Mask(VLSM) .VLSM (Variable Length Subnet Masking) c ngha thc hin nhiu hn mt

mt n trn cng lp (class) chnh ca mt mng. N cho php s dng a ch IPhiu qu hn cho my (host) v cc mng con (subnet). iu ny l rt cn thit

trn mt mng khng c khng gian a ch IP lnVD : Cho trc net 192.168.1.0 /24. Yu cu trin khai 3 network sau: HCM100 my, Cn Th 50 my, H Ni 50 myMn 1 bit chia subnet, nh vy gi tr netmask mi l /25 (255.255.255.128).Khi ta c 2 network:

Net 0:192.168.1.0 (khng dng v y l a ch i din cho net0)192.168.1.1192.168.1.2

.........192.168.1.126192.168.1.127 (khng dng v y l a ch broadcast ca net0)

Net 1:192.168.1.128 (khng dng v y l a ch i din cho net1)192.168.1.129192.168.1.130.........192.168.1.254192.168.1.255 (khng dng v y l a ch broadcast ca net1)

Chn Net0 cho HCM, lc mt my HCM s c IP dng 192.168.1.x (x chyt 1 n 126), netmask: 255.255.255.128.By gi ta chia net1 ra lm 2 bng cch mn thm 1 bit na: /26(255.255.255.192)Ta s c 2 net mi, mi net c 62 host (64 - 2)net1a:

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192.168.1.128 (khng dng v y l a ch i din cho net1a)192.168.1.129192.168.1.130.......192.168.1.190

192.168.1.191 (khng dng v y l a ch broadcast ca net1a)

net1b:192.168.1.192 (khng dng v y l a ch i din cho net1b)192.168.1.193192.168.1.194.....192.168.1.254192.168.1.255 (khng dng v y l a ch broadcast ca net1b)

Ta chn net1a cho Cn Th v net1b cho H Ni.Nh vy trong Vit nam ti HCM gi tr netmask l /25, cn th v h ni l /26

2.1.3. CIDRCIDR lm gim "gnh nng" cho cc Internet Router (B nh tuyn trong

mng Internet) bng cch "gp" cc ng truyn (knh truyn) v cho php mta ch IP cho th "i din" cho hng ngn a ch ("nt" mng khc) c nhu cuc "phc v" bi cc nh cung cp ng trc Internet (Internet backboneprovider). Tt c cc gi tin gi cho cc a ch s c chuyn n cho ISP (vd M l US Sprint hoc MCI). Vo nm 1990, c khong 2000 knh truyn

trn mng Internet. Nm nm sau, con s ny tng ti 30.000 knh truyn.Khng c k thut CIDR, cc router trong mng Internet khng th h tr slng cc "nt" mng Internet lin tc gia tng nhanh chng.

Hnh 1.3 : VD v s dng CIDR

2.1.4. NAT (RFC 1631)L phng php vn dng trng header ca gi tin IP qua a ch ch,

a ch ngun hoc c ch, c ngun c thay th bng a ch khc do ngiqun tr thit lp.

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Hnh 1.4 : VD v NATNAT cho php cc thit b hot ng bin gii ca mng dng stub (mng

ch c 1 ng sang mng hng xm ca n).2.1.4.1. Cc loi a ch trong NAT

Trong NAT. ta nh ngha 1 s loi a ch sau Inside local addr : l a ch IP gn cho 1 host trong mng, thng l a

ch private Inside globe addr : l a ch public c cung cp bi ISP. N i din

cho 1 hoc nhiu a ch Inside local Out side local addr : l a ch ca mt host bn ngai mng c bit

bi cc host trong mng Outside global addr : l a ch m ISP gn cho 1 host ngoi mng

2.1.4.2. Hot ng ca NATKhi gi tin t trong mng i ra s chuyn i t a ch local addr sang

global addr. Khi gi tin i t ngoi vo,, Router s tham kho bng NAT nh

x a ch global thnh a ch local.C 3 loi NAT Static NAT : a ch ca c mng khi i ra ngoi c thay th bi 1 a

ch duy nhto Cho php giu thng tin ca mng bn trong vi cc mng bn

ngoi, tng thm tnh bo mto Ch cho php nh x 1-1 gia a ch local v a ch globalo Hu dng vi cc a ch ca host phi c truy cp t

internet(DNS Server hay Mail Server) Dynamic NAT : a ch c mng khi i ra ngoi c thay th bi 1 a ch

trong 1 tp hp cc a ch c gn cho trc. PAT : a ch ca mng khi i ra ngoi c s dng NAT kt hp vi 1 s

iu kin (port)o S dng 1 gi tr duy nht source port gn cho gi tr inside

global add nhm phn bit cc phin translationo Gi tr source port c m ho bi 16 bits nn n tng s phin

NAT l 2 m 16.

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o Nu gi tr source port c s dng, PAT c gng tm gi tr utin avai trong khong 0-511, 512-1023, 1024-65535.

Hnh 1.5 : Hot ng ca PAT2.1.4.3. u v nhc im ca NAT

Nh thy trn, s dng NAT c 1 s u v nhc im sau :u im

NAT cho php tit kim a ch IP bng ch cho php s dng a ch

private trong c mng intranet. NAT tng s tin cy ca kt ni ra ngoi internet. Mun thay i 1 mng cn phi nh a ch li ton b mng. Chi ph s t

l thun vi s lng host cn phi cn phi chuyn i sang a ch mi.NAT cho php chin lc onh a ch c vn tn ti v ng thi vn htr chin lc a ch mi

Nhc im NAT lm tng tr : tr trong qu trnh switching. CPU s phi kim tra mi

gi tin xc nh n c phi translate gi tin hay ko? V sau thayi IP header thm ch c TCP header.

1 nhc im ln na l khi ta s dng NAT, ta ko c kh nng kim trangun gc ca a ch IP trong cc kt ni end-to-end. Rt kh tm radu vt ca gi tin tri qua nhiu ln thay i a ch qua nhiu ln NAT.

NAT khin cho 1 s ng dng s dng a ch IP ko lm vic do n giua ch IP. Cc ng dng s dng a ch vt l m ko s dng tn min sko th ti c a ch ch m a ch ny b translate qua NAT.

NAT h tr TCP/UDP tuy nhin n ko cho php cc a ch ch hay ngunca cc ng dng truyn d liu nh HTTP, TFTP, Telnet. Cc ng dngm NAT h tr : ICMP, FTP, NetBIOS over TCP/IP, DNS, Real Audio

2.2.nh tuynCc Router quyt nh ng i ca gi tin. Cc giao thc nh tuyn s s

dng cc phng php ng duy tr cc thng tin ny. Tuy nhin cc gi tin ca ch ch trn ng internet backbone phi c nh tuyn qua cc Routernondefault s dng giao thc nh tuyn BGP. Cc Router ny phi duy tr 1 listtt c cc tuyn trn Internet, Routing Information Base(RIB). Mi thnh phn

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trong RIB l 1 tuyn. Theo s pht trin ca Internet, kch thc ca RIB ngycng ln v tr nn qua phc tp tnh ton.

2.3.Thit lp cu hnh cho cc thit b phc tpTt c cc thit b IPv4 u phi c cu hnh bng tay hoccu hnh theo

kiu statefull (DHCP). Vi s pht trin ca Internet hin nay, ngy cng c nhiuthit b s dng a ch IP, chng ta cn phi c 1 c ch cu hnh t ng v ngin hn.

2.4.Vn end-to-end2 im u cui c th hot ng vi nhau m ko cn bt v ng truyn

trung gian. iu ny cho php tng ng dng hot ng 1 cch n gin hn. Tuynhin do vic s dng cc ko gian a ch private v NAT khin cho IPsec ko thp dng. IPsec l mt thc m bo security tng network. Ngoi ra, ko phing dng no cng chy trn NAT. NAT h tr TCP/UDP tuy nhin n ko cho

php cc a ch ch hay ngun ca cc ng dng truyn d liu nh HTTP,TFTP, Telnet. Cc ng dng m NAT h tr : ICMP, FTP, NetBIOS over TCP/IP,DNS, Real Audio

3. Cc u im m IPv6 cung cpNh ni trn, IPv4 c kh nhiu nhc im, trong quan trng nht l

vic khng gian a ch IPv4 ang cn kit. iu ny dn n tt yu phi ra imt th h a ch mi gii quyt c nhng nhc im ca IPv4, l IPv6.Th h a ch IPv6 ko nhng gii quyt c nhng vn ca IPv4 m cn cungcp thm 1 s u im :

Khng gian a ch ln Kh nng m rng v nh tuyn H tr end to end d dng hn Ko c phi phn mnh, ko cn trng header checksum. Security : do IPv6 h tr IPsec, n lm cho cc node IPv6 tr nn an ton

hn(thc ra IPsec c th hot ng c vi c IPv4 v v6. Autoconfiguration : IPv4 cung cp 2 c ch config 1 node. Cu hnh tnh

th ko cho php thay i theo thi gian, trong khi cu hnh ng cho phpmt node request thng tin cu hnh v thng tin c th thay i theo

tng phin. Cu hnh ng trong IPv4 lin quan n statefulautoconfiguration bi v thnh thong cc thng tin cu hnh cn c luli(a ch MAC). IPv6 thm vo 1 c im na l statelessautoconfiguration cho php kt ni vo mng m ko cn contact vi server.

Mobility : cho php h tr cc node mobile IP Hot ng : trng IPv4 header lm thay i kch thc ca gi tin IP v

thng b b i ko tnh n. Do cc Router thng chuyn hng hac t

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chi cc gi khi n busy. y chnh l l do ta ko trin khai IPsec trn nnIPv4. Cc Router IPv6 hot ng khc gia trn cch x l khc i vi ach IP v cc tuyn

Cost : gim gia thnh v cng tc qun l, tng an ninh, hot ng tthn, cn t tin hn ng k a ch IP. Cc chi ph ny s cn bng chi

ph cho vic chuyn t IPv4 sang IPv6.

Chng 2 : Tng quan v a ch IPv6

1. Cu trc v cc loi a ch IPv61.1.Cu trca ch IPv6 c chiu di 128 bits, nn vn nh a ch l ht sc kh khn.

Hnh 2.1 : So snh ko gian a ch IPv4 v IPv6

Ngi ta quy c vit 128 bits thnh 8 nhm, mi nhm 2 bytes mi byte biudin bng 2 s h 16, mi nhm ngn cch nhau bi du :

Hnh 2.2 : 1 s VD vit a ch IPv6

Quy tc rt gn : Trong 1 a ch, 1 nhm lin tip cc s 0 c th thay th bng ::. Quy tc

rt gn ny ch c php s dng 1 ln vi 1 a ch

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Ngoi ra, cn c th vit cc a ch theo cc tin t (prefix), l cc bit caoca a ch IPv6, iu ny c li cho vic nh tuynVD : FEDC:BA98:7600::/40

1.2.Cp pht a ch IPv6

Cp pht Cc bit u T l vi ton b khng gianUnassigned 0000 0000 1/256Unassigned 0000 0001 1/256Cc a ch NSAP 0000 001 1/128Unassigned 0000 01 1/64Unassigned 0000 1 1/32Unassigned 0001 1/16Cc a ch Global Unicast 001 1/8Unassigned 010 1/8Unassigned 011 1/8Unassigned 100 1/8Unassigned 101 1/8Unassigned 110 1/8Unassigned 1110 1/16Unassigned 1111 0 1/32Unassigned 1111 10 1/64Unassigned 1111 110 1/128Unassigned 1111 1110 0 1/512

a ch Link-Local Unicast 1111 1110 10 1/1024a ch Site-Local Unicast 1111 1110 11 1/1024a ch Multicast 1111 1111 1/256

Bng 2.1 : Cp pht a ch IPv6Ta c th thy, mi ch c 15% khng gian a ch c s dng trong giai

on ny, cn li 85% c d tr cho tng lai.C 2 c ch cp pht l :

A. Cp pht theo nh cung cpa ch IP s c cc trng ID ca cc nh cung cp TLA ID : nh danh nh cung cp cao nht trong h thng cc nh cung cp

dch v NLA ID : nh danh nh cung cp tip theo SLA ID : nh danh cc site ca khch hng cuiCc TLA l cc nh cung cp cao nht. Cc NLA l cc ISP cn phi xin cp

gi tr NLA ID ca mnh thng qua cc TLA. C 1 s phog php xin cp gi trNLA ID nh sau :

Xin cp qua 6bone community : y l mng th nghim IPv6 trn toncu. Khi tho mn 1 s k ISP s c cp pht IP

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Xin cp qua RIP Gi lp a ch IPv4 vo IPv6 : phng php ny thun li cho vic th

nghim IPv6 trn nn IPv4. 32 bits cui s l a ch IPv4, cn TLA ID cdng 2002::/16

Vi 1 end-user-site sau khi xin a ch s c cp pht a ch v cc TLA

ID, NLA ID ri gn gi tr SLA ID nh danh cc site trong t chc.Tuy nhin, vi phng php ny s ko ti u vi cc t chc ln tri trn mt

khu vc a l rng vi nhiu chi nhnh m mt s trong cc chi nhnh li s dngdch v ca cc nh cung cp khc nhau.

B. Cp pht gia trn v tr a l :Cc a ch c cp pht gia trn khu vc a l v cc nh cung cp ch

cn duy tr cc tuyn bn ngoi lin kt vi cc tuyn ca h. Tuy nhin, ccnh cung cp ko thch phng php ny bi n lm phc tp ho thm qu trnh

qun l a ch. Do s pht trin ca cng ngh cc kh khn trong vic cp phta ch theo nh cung cp c gii quyt. Vic cp pht a ch theo v tr al ch cn oc pht trin nhm cho nhng mc ch automatic v dynamicconfiguration bao gm c vic t ng nh li a ch ton mng khi ISP thayi.

1.3.Cc loi a ch IPv61.3.1. a ch unicast :

cs dng phn bit cc host n l trn mt mng. Bao gm 3 loi ach :

Global : c dng nh dng cc giao din, cho php thc hin kt nicc host trong mng IPv6 ton cu. N ging nh a ch IPv4 nh danh 1host trong mng Internet hin nay.

Link local : nhn dng ng kt ni ni b, ko c a vo nh tuyn. Site local : nhn dng trong phm vi ni b, c th c nhiu nhm.

1.3.1.1. Global unicast

Hnh 2.3 : Cu trc a ch Global unicast

FP=001 : nh dng prefix vi a ch global unicast TLA ID : nh danh nh cung cp cao nht trong h thng cc nh cung

cp dch v RES : cha s dng NLA ID : nh danh nh cung cp tip theo

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SLA ID : nh danh cc site ca khch hng cui Interface ID : c nh danh theo chun EUI-64. Tu thuc vo chun

cc giao tip khc nhau m c a ch interface khc nhau

Nh vy a ch global unicast c thit k phn cp : 48 bits public topology 16 bits site topology 64 bits giao din

Hnh 2.4 : cu trc phn cp ca iach unicast

1.3.1.2. Local unicasta ch local unicast li c chia lm 2 loi : Link local : c s dng t a ch cho cc kt ni n Site local : c dng t a ch cho cc interface trong 1 site

A. Site localCu trc a ch site local unicast

Hnh 2.5 : Cu trc a ch site localQuy tc nh tuyn Router ko th chuyn cc gi tin c a ch ngun hay ch l a ch site

local unicast ra ngoi mng Cc a ch site local ko th chn ng trn ton b internet. Chng ch c

th dng chuyn i gia 2 chng trn cng 1 site

B. Link local

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Hnh 2.6 : Gn a ch link local

Cu trc a ch link local

Hnh 2.7 : Cu trc a ch link locala ch link local ko tham gia nh tuyn

Hnh 2.8 : gn ia ch trong 1 link

1.3.2. a ch Anycastc gn cho 1 nhm cc giao din v cc gi tin c gi n a ch

anycast s c chuyn n giao din gn nht c a ch ny.V mt cu trc, a ch anycast ko phn bit vi da ch unicast, khi a ch

unicast c gn cho nhiu giao din n s tr thnh anycastMc ch ca a ch anycast l h tr nhng t chc c cu trc mng

phn cp. Khi a ch anycast c gn cho cc Router m cc Router ny cchia thnh cc vng. Khi 1 packet n Router cao nht n s c chuyn n

ng thi cc Router trong onHn ch ca a ch anycast Ko c s dng l a ch ngun ca 1 gi tin IPv6 Ko c gn cho 1 host IPv6, ch gn cho Routera ch anycast c bit dng gn cho 1 subnet

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Hnh 2.9 : cu trc a ch anycast dng gn cho 1 subneta ch ny c s dng cho nhng giao din cn giao tip ng thi vi 1 tp

cc Router trn mng1.3.3. a ch Multicast

c dng gn cho 1 tp cc giao din. Mt gi tin c a ch ch lmulticast s c gi n tt c cc giao din c a ch multicast ny

Cu trc a ch multicast

Hnh 2.10 : cu trc a ch multicast ngha cc trng :

8 bit u tin ca a ch 11111111 : nh ngha cho a ch multicast.

bit tip theo ca a ch multicast l cc bit c (flag)3 bt u ko dng n. Bit c th t c bit n nh mt bit nt m.Nhim v ca n l biu th xem a ch l mt a ch tm thi haythng xuyn. Nu a ch l a ch thng xuyn th bit ny s cgn bng 0 cn ngc li n s c gn bng 1.

4 bits tip theo l ID scope : dung gii hn phm vi nhm a chmulticast

Bng 2.2 : Trng ID scope

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112 bit cn li c s dng cho nhm ID. Kch thc ca nhm ID chophp cc a ch multicast dng ht 1/256 phn khng gian a ch caIPv6.

1.3.4. Cc dng a ch IPv6 khc

Ngoi 3 dng a ch trn, IPv6 cn quy nh 1 s loi a ch c bit khc : a ch ko xc nh ::/128 : a ch ny ko c gn cho interface no.

Host khi mi khi to c th s dng a ch ny nh a ch ngun ca ntrc khi n c a ch.

a ch loopback 0:0:0:0:0:0:0:1 : mt node c th s dng a ch ny gi gi tin IP cho chnh n. N ko c s dng nh a ch ngun

a ch IPv4 trong IPv6

Hnh 2.11 : Cu trc a ch IPv4 trong IPv632 bit thp s l a ch IPv4, 96 bits cao gn bng 0

2. Cu trc gi tin IPv6Cu trc gi tin IPv6 c dng nh sau :

Hnh 2.12 : Cu trc gi tin IPv6Header ca gi tin IPv6 bao gm 8 trng (40bytes) so vi IPv4 c 12 trng

v di 20 bytes (nu ko c trng option) hoc 60 bytes (nu c trng option).Do cu trc ca trng header ca IPv6 n gin hn nn vic x l thng tin snhanh hn.

Header n gin hn l do s thay i ca 1 s phng thc hot ng Header c cng kch thc nn b trng header length Qu trnh fragmentation ch do source node thc hin nn cc Router ko

tham gia vo qu trnh fragmentation trng fragmentation ko cn thitTuy nhin qu trnh ny ko nh hng n s tin cy ca qu trnh truyn gi

tinExtension header : IPv6 extenssion header l mt c ch m bng cch

nhng thng tin ca lp internet c m ho trong nhng header ring bit c thc trong header ca IPv6 v cc header ca cc lp trn ca cng 1 gi tin

2.1.Cu trc Header ca gi tin IPv6

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Hnh 2.13 : So snh header ca gi tin IPv4 v IPv6

Cc trng trong header ca gi tin IPv4 Cc trng trong header ca gi tin IPv6Version : u l 4 bits c IPv6 v v4.Trng ny phi c c 2 version IPv6 c th cng tn ti vi IPv4

Header length : ko c IPv6 do headerca cc gi tin IPv6 c cng kch thc,IPv4 cn trng ny do kch thcheader ca n c th thay i do c thmtrng optionType of service/Differentiated Services: trng DS c s dng c IPv4 vv6 bao gm 6 bits ch ra cch m gitin c x l Router m bo QoSDatagram length : tr thnh trng

payload length IPv6. IPv4 trngDL ch ra chiu di ca ton b gi dliu k c header, R c th tnh chiu dipayload bng cch tr chiu diDatagram cho chiu di Header. IPv6th do chiu di header xc nh nnch cn trng PLDatagram Identification : dng xcch datagram ny l do gi nofragment ra. Do IPv6 ko cho php cc

node trung gian fragment gi tin nntrng ny ko cnFlags : c s dng cho phpfragmentFragment Offset : c s dng chophp fragmentTTL :Protocol : ch n giao thc lp cao

Version :Differentiated Services : 6 bit, 2 bitdng cho tng lai, cn 4 bit ch priority

ECN(Explicit Congestion Notification): 2 bitsFlow Label : 20 bits dng xc nhgi tin thuc cng 1 lung. Do mt nodec th l ngun ca nhiu ngun, gi trFL v ch ngun xc ch duy nht 1lungPayload length : 16 bits cha 1 snguyn ch ra chiu di trng payloadbng bytes bao gm c trng IPv6

extension headerNext header : ch ra giao thc nowocj dng x l gi tin.Hop limit : 8 bits. Mi ln 1 nodeforward gi tin n s gim gi tr catrng ny i 1. Nu trng ny = 0, gitin s b hu.Sadd, Dadd

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hn s dng d liu c ng gi vogi tin IPv4. L trng Next headertrong IPv6 ch raHeader checksum :Source add, Destiantion add :

IP option : ko c IPv6

Bng 2.3 : So snh header ca IPv4 v Ipv6

2.2.Extension headerMi loi ca exension header c nh ngha bi 8 bits trng Next header

ca header trc

Hnh 2.14 : cu trc gi tin IPv6 v trng extension header

Cc gi tr ca trng next header

Next header type ValueHop-by-hop OptionsIPv6RoutingFragmentAuthentication

0041434451

to ng hm IPv6

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Destination OptionsEncapsulating Security PayloadNo next header

605059 Ko c header tip theo header ny

Bng 2.4 : Cc gi tr ca trng Next headerCc loi extession header : Hop-by-hop : mt s gi tin IPv6 c yu cu ch do node ngun v node

ch x l, cn li hu ht th u cn t nht 1 Router trung gian x l.Header hop-by-hop c s dng khi 1 trong s cc option cn phi cx l bi mi node trn ng t ngun n ch

Routing : cho php node gi 1 gi tin n 1 hoc nhiu Router ccRouter x l v nh tuyn n ch

Fragment : mc d IPv6 ko cho php cc Router trung gian fragment gitin, cng vic ny l ca cc node ngun v ch. Tuy nhin khi node ngunthy rng n cn phi gi gi qua wongf truyn c MTU nh hn kchthc gi th cc node trung gian c php fragment gi tin v gi tin c

thm trng fragment Authentication : khi s dng phng php xc thc c an ton cao

header ny c s dng Destination : gii hn ch nhng node ch no mi x l nhng option m

gi tin mang theo. Encapsulating Security Payload : khi ta s dung jphng php m ho c

an ton caoCc extension header c sp xp theo 1 th t nht nh sau header chnh

m bo tt c cc thng tin optional c x l bi node ch cng nh ccnode trung gian trong khi cng thi gian cho php cc node x l gi tin theo

thng tin optional.VD : hop-by-hop c t ngay sau header chnh v n phi c x l bi tt

c cc node trung gianDestination c t di cng v cc node trung gian ko nht thit phi x l

option nyTh t cc extension header c khuyn co a ra trong RFC 2460 IPv6 header Hop-by-hop Destination option Routing header Fragment header Authentication header Encapsulation Security Payload header Destiantion option header Upper layer header

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Hop-by-hop option v Destination Option Header c th cha 1 hoc nhiuoption. Ko ging cc IPv6 extenssion header khc chi thc hin 1 chc nng, 2header kia l cc header ti to v ch c phn bit bng cch n hot ng

Hop-by-hop : cha cc option c x l ti mi node Destination : cha cc option ch c x l ti node ch

3. ICMPv6L giao thc s dng bn tin ICMPv6 thng bo li hoc thu ht cc p

ng t 1 node ly thng tin cn thit. Cc ng dng nh : ping, trace route, PathMTU Discovery, Neighbour discovery gia trn ICMPv6. Bn tin ICMP cng gi trong gi tin IP v c xc ch bi trng next header = 58

3.1.Cu trc

Hnh 2.15 : Cu trc bn tin ICMP

ngha cc trng Type : 8 bit , ch ra loi bn tin ICMPv6, (0-127) : l bn tin error mess,

(128-255) l bn tin thng bo Code : 8 bits ph thuc vo trng type

Checksum : 16 bits Mess body : cha d liu

3.2.Mt s loi bn tin ICMPBn tin ICMP wocj to ra khi c 1 s li : router ko th gi c gi tin,

node ko th khi phc wcj gi tin b li, .Ch rng khi 1 link ang tc nghnnode ko bao gi gi bn tin ICMP thng bo tc nghn bi iu ny ch lmmi th thm t hn. Mt s phng thc khc tng cao hn s c dng gii quyt vn ny.

3.2.1. Destination unreachable : c gi cho node ngun khi R nhn

c gi tin m n ko th gi i u c.Cu trc bn tin

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Hnh 2.16 : cu trc bn tin ICMP des unrechableCc gi tr c th c ca trng code 0 : ko c tuyn ch : R ko c tuyn ch tng ng vi a ch ch ca gi

tin. Bn tin ny ch c gi vi nhng R ko c default route 1 : communication with administratively prohibited : bn tin ny wocj gi

bi firewall khi 1 loi traffic b cm wocj gi ti 1 host bn trong firewall 2 : cha c gn 3 : addr unreachable : 4 : port unreachable : c to bi node ch khi cc tng trn ko bt s l

gi tin ny th no

3.2.2. Packet too big: c gi cho node ngun khi Router nhn c gitin ln hn gi tr MTU ca link

Cu trc bn tin

Hnh 2.17 : Cu trc bn tin ICMP packet too big

3.2.3. Time exceeded :C 2 loi Khi gi tin chy trong mng trong khong thi gian qu lu m ko n ch

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Gi tin vt qu c thi gian phn mnh v ghp mnh qu luCu trc bn tin

Hnh 2.18 : Cu trc bn tin ICMP time exceededCc gi tin qu lu trong mng s b loi b khi gi tr vt qu gi tr hop

limit. R s xo cc gi tin c gi tr trng hop limit = 0 hoc 1 v gi bn tinICMP v cho node ngun

1 : hop limit vwotj qu gii hn 0 : qu time out m ko gi cBn tin ny c dng cho chc nng trace route u tin 1 bn tin c gi n ch vi hop limit =1, R u tin nhn

c s gi li bn tin time exceeded v node ngun s bt R u tin trnng truyn.

Ngun li gi bn tin th 2 vi hop limit = 2 v R thu 2 s gi li bn tintime exceeded

C th cho n khi gi tin n c ch v node ngun s c thng tin vtt c cc R trung gian

3.2.4. Parameter problem : c gi cho node ngun khi c vn vi 1vi phn ca gi tin IPv6 hoc trng extension header khin choRouter ko th x l v phi xo gi tin.

Cu trc bn tin

Hnh 2.19 : Cu trc bn tin ICMP parameter problem

3.2.5. ICMPv6 Echo Funtion : echo request v echo reply

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Echo request : c gi ti tt c cc a ch valid IPv6 c th thm gi trEcho req ident, seq num v mt s d liu. Gi tr ident v seq phn bit cc gitr reply khc nhau. Data l gi tr optional

Khi 1 node nhn bn tin req n phi gi li bn tin Echo reply vi cc gi trident, seq, v data ging nh bn tin Echo request

Cu trc

Hnh 2.20: Echo Request Hnh 2.21 : Echo reply2 bn tin ny l thnh phn ca lnh Ping

3.3.Qu trnh phn mnh v xc nh MTU3.3.1. Qu trnh phn mnh

Qu trnh phn mnh trong IPv6 ch c cho php gia node ngun v ch,iu ny lm n gin trng header v gim cc thng tin overhead cho nhtuyn. Cc node IPv6 c th c php phn mnh nu cn thit s dng trngfragmentation tuy nhin cc Router trung gian hoc cc node khc ko c phpphn mnh gi tin ln hn MTU

IPv4 cho php phn mnh nu gi tin cha phn mnh mt qu nhiu thigian n ch. Cc Router trung gian thc hin vic phn mnh c th thay iheader ca gi tin n node ch c th ti hp cc mnh li thnh gi tin honchnh.

S dng phn mnh cho php cc node hot ng trong cc mi trng mngkhc nhau hot ng vi nhau tt hn. Node ngun ko cn bt v node ch cngnh thng tin v ng truyn n ch. iu ny lm gim thng tin m nodengun cn phi lu tr v mng v cho php kh nng m rng cao. Tuy nhin,phn mnh lm thm cc header, overhead, v lm Router tn CPU x l.

C 2 cch hn ch phn mnh l : Cch 1( c s dng IPv4) :path MTU discovery : Router s gi 1

gi tin c kch thc bng MTU ca link u tin n ch nu gi tin nlink no m n b phn mnh, Router phn mnh s gi li bn tinICMP ch ra MTU ca link l bao nhiu. Qu trnh c tip din cho n khiR xc nh c link path MTU

Cch 2 : l hn ch n mc ti thiu kch thc gi tin tt c cc linku c th chp nhn c

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3.3.2. IPv6 path MTU discoveryIPv6 s dng c 2 cch hn ch phn mnh trnMTU cho IPv6 c nh ngha RFC 2460 l 1280 bytesTuy nhin IPv6 khuyn co nn s dng c ch MTU discovery s dng bit

dont fragment trong trng flag fragment cc R trung gian gi li bn tinICMP error bo gi tin qu ln

Hnh 2.22 : Path MTU discovery

4. Neighbour discoveryCc node IPv6 trong cng 1 link s dng ND khm ph s tn ti ca nhau,

a ch tng 3 ca nhau, tm Router v duy tr thng tin v ng i xydng neighbour. Nh vy cc giao thc lin quan nh ARP ko cn cn thit na

4.1.Cc bn tin ICMP s dng trong neighbour discoveryND s dng 1 s loi bn tin ICMP sau thc hin cc chc nng ca mnh : Router solicitation : khi 1 inter bt u hot ng, host s gi Router

solicitation yu cu Router gi li Router Adv Router Adv : R s thng bo s tn ti ca n v cc thng s theo chu k

hoc khi nhn c bn tin R Solic Neighbour Solicitation : c gi bi node xc nh a ch link layer

ca neighbour hoc kt xem neighbour c reachable hay ko? Neighbour adv : tr li li bn tin neighbour solic

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Redirect : c s dng bi Router ch cho host first hop tt hn nch.

4.2.Bn tin Router Solicitation :Cho php 1 node yu cu R gi R adv ngay lp tc. Bng cch ny 1 node c

th ghi nh a ch IP v a ch tng 2 ca Router. Router solicitation c gi

multicast ti tt c cc Router trong bt c phm vi no ca gii hn a ch chIPv6. Tt c cc Router trong phm vi ny phi tr li li vi bn tin Router adv.Bnh thng Router s gi bn tin qung b ny trong 1 chu k nht nh v ngi ti tt c cc node c a ch multicast. Tuy nhin khi p ng yu cu cahost n ch gi li cho host gi bn tin Router Solicitation.

4.2.1. Cu trc bn tin Router Solicitation :

Hnh 2.23 : Cu trc bn tin Router Solicitation

4.3.Mt s chc nng m ND cung cpIPv4 s dng ARP nh x a ch IP vi a ch tng 2, nhng c 1 s hn

ch. ND trong IPv6 cng c chc nng ny tuy nhin n cn cung cp 1 s chcnng phc tp khc

Router discovery : cung cp c ch xc ch local router Prefix discovery : Parameter discovery : c ch xc nh cc thng s ca local link

network, MTU, hop limit, Addr autoconfiguration : Addr resolution : xc nh a ch lp 2 ca 1 host neighbour m ch bt a

ch IP ca n. Nexthop detemination : khi mun gi 1 gi tin i, host phi xc ch a chi

gi. Quyt nh ny gia trn a ch ch ca gi tin v host cn phiquyt ch gi gi tin n thng ch nu trong cng 1 local link hay gin router nu ko trong cng 1 local link.

Neighbour unreachable detection : ht cn c ch cho php xc nhneighbour ca n c reachable ko? Nu l router th default route ngc s dng

Duplicate addr detection : xc nh a ch ny c s dng cha?Redirect :

Link-layer addr change : 1 node khi pht hin a ch lp 2 ca n thay ic th gi multicast update thng tin thay i ny.

Inbound load balancing : 1 node c nhiu a ch lp 2 trn cng 1 inter cth chia ti trn cc inter .

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Load balancing : Anycast addr : Anycast addr c dng xc nh 1 trong 1 tp hp cc

node cung cp nhng dch v tng ng nhau. Cc node trong 1 locallink c th c config nhn ra cng 1 a ch anycast. ND x l a chanycast bng cch cc node nhn cc bn tin Neigh adv

Proxy adv :

5. IPv6 autoconfigurationStateful autoconfiguration : DHCPv6 c pht trin t BOOTP. DHCP cho

php host config bng DHCP server. Server s lu nhng thng tin v a ch IP,a ch link layer ca tt c cc node s dng dv ny trnh c 2 node s dngcng 1 a ch IP

Stateless autoconfiguration : cho php node IPv6 c th t config m ko cnserver

Router v network renumbering : vic s dng a ch local cho php mtmng c th chuyn t nh cung cp ny sang nh cung cp khc. Cc a ch sitelocal cho php ch tuyn trong mng trong khi nh tuyn ngoi mng s cthc hin bng cch config li router gateway.

5.1.Stateful v Stateless autoconfiguration :DHCP server c th cung cp a ch theo 3 cch : Automatic : DHCP server s gn a ch IP 1 cch lu di cho host Dynamic : DHCP s cp pht a ch cho host trong 1 khong thi gian nht

nh

Manual : ngi qun tr s cp pht a ch IP cho host v DHCP ch cdng vn chuyn a ch ny n hostTrong c 3 trng hp, u i hi server phi lu gi thng tin v a ch

cp pht.Stateless autoconfiguration li ko i hi Server phi lu gi thng tin v a

ch cp pht v cho php 1 node c th t config mt cch c lp.2 phng php ny c th hp tc vi nhau thng qua giao thc ND

5.1.1. DHCPv6Cc bn tin : c ng gi s dng UDP.Client ban u cha c a ch IP hoc cha c DHCP cp pht a ch IP

s gi yu cu n n i ch multicast ginh ring cho DHCP server : Tt c cc DHCP agent v server : FF02::1:2 Tt c cc DHCP server : FF05::1:3Tip theo client s tip tc gi gi tin yu cu cp pht a ch multicast mc

d c a ch unicast c th s dng DHCP relay agent gi gi tin t clientn 1 DHCP server xa. iu ny s hiu qu hn so vi vic client gi unicasttrc tip n server.

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Cc loi bn tin DHCPv6 SOLICIT : client gi bn tin ny xc ch DHCP server ADV : server gi li bn tin ny tr li bn tin SOLICIT ch ra rng n

ang cung cp dch v DHCP REQ : client gi bn tin ny yu cu cc thng tin CONFL : client gi bn tin ny n cc server avai thng bo rng a

ch n c cp pht xung t vi a ch trong link m n lin kt RENEW : client gi bn tin ny n server cp pht a ch cho n

gia han a ch ny REBIND : client gi bn tin ny n xin gia hn a ch ng thi xin thm

1 s thng s, bn tin ny oc gi sau khi bn tin RENEW ko c tr li. REPLY : cha cc thng tin config tr li cc bn tin SOLICIT, REQ,

RENEW, REBIND, RELEASE : client gi bn tin ny ti server cp pht a ch ny cho n

thng bo ko s dng a ch ny na DECLINE : client gi bn tin ny ti 1 server ch ra rng a ch ny

c s dng trogn link RECONFIG : server gi bn tin ny cho client ni rng server mi c

thng tin update mi v client phi gi bn tin RENEW hoc REQ nhnthng tin update

INFO-REQ : client gi bn tin ny ti server yu cu cc thng sconfig, m ko c a ch IP

RELAY-FORW : relay agent gi bn tin ny chuyn tip bn tin tiserver hoc ti mt agent khc

RELAY-REPLY : Server gi bn tin tr li n relay agent chuyn nrelay agent khc hoc client

Qu trnh trao i client/server s dng 2 bn tin : bn tin REQ ca client vREPLY ca server.

Client ko cn cp pht a ch IP m m cn 1 s thng tin config khcnh : a ch cc DNS server. Client s bn tin DHCP REQ ti a chmulticast ca tt c cc DHCP relay agent v server. Server s gi li bntin tr li.

Client yu cu gia hn a ch IP. Client gi bn tin RENEW v servergi li bn tin thi gian m client c th tip tc s dng a ch ny

Cp pht a ch IP : thng thng qu tnh ny cn 4 bn tin tuy nhin cth thc thin qu trnh ny trong 2 bn tin khi server c thng tin cppht cho client ny lu trong c s d liu.

Qu trnh trao i s dng 4 bn tin : theo th t sau SOLICIT-ADV-REQ-REPLY

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5.1.2. Stateless Autoconfiguration :Gia trn EUI-64 cho php xc nh 1 cch duy nht 1 node trong 1 local link.

Nu 1 node s dng a chi link local c ngha l tt c cc node c th x l gitin gi n hoc c gi t 1 a ch link local unicast. Tuy nhin gi tin ny ko

c gi ra ngoi link.S dng ND cho php cc node ring bit c th thu thp thng tin router v

cc server trong link. Mt phn cu giao thc ny cho php xc nh networkprefix. Do , cc nod c th khm ph tt c thng tin n cn m ko cn dngDHCP

Qu trnh t config bao gm cc bc sau : T to 1 link local addr cho node Kim tra tnh duy nht ca a ch trong link : s dng ND gi gi tin ti

a ch m node va to, nu c host s dung a ch ny ri n s tr lili v qu trnh auto config kt thc, node phi c config bng tay

Quyt nh xem thng tin no c th t config, thng tin no cn phi yucu

Mc ch ca stateless autoconfiguration : Hn ch vic config bng tay trc cho cc kt ni : cc node c th ko cn

phi config trc khi n c kt ni vo link. Ta gi s rng mi inter cth to ra 1 s duy nht cho mi inter(n gin nht chnh l a ch linklayer ca n)

Hn ch cc Stateful server/router trong nhng mng nh : trong mng nhvic s dng DHCP l ko cn thit

Hn ch cc statefull server trong cc mng ln : trong mng ln to cca ch site local v global addr host phi xc nh prefix xc nh mngm n kt ni vo. Router nh k gi R adv c kit k tp hp cc prefixs dng trong mng

Lm qu trnh site renumbering d dng hn : Kim sot qu trnh cp pht a ch: ngi qun tr cn phi ch r khi no

dng statefull khi no dng stateless hoc khi no dng c 2. R adv c bitflag ch ra c ch no oc dng

5.2.Router v network renumbering

6. nh tuyn trong IPv6V c bn nh tuyn trong IPv6 ko khc nhiu so vi nh tuyn trong IPv4.

N cng c chia thnh 2 loi Interior v Exterior Cc giao thc Interior c s dng bn trong mt min c kt ni ti

internet

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Cc giao thc Exterior c s dng trn mng backbone vi cc minc kt ni vo do vy c ch ca n phc tp hn nhiu so vi Interiorrouting protocol

Cc giao thc nh tuyn hot ng gia trn cc thut ton nh tuyn.C 2thut ton nh tuyn c bn nht l distance vector v link state

6.1.Distance vector:Thng tin nh tuyn bao gm : hng khong cch gia cc nodeHot ng Ban u, mi Router thu thp thng tin nh tuyn v cc mng kt ni trc

tip vo n. nh k, cc Router s gi bn copy ca bng nh tuyn cho cc router

hng xm. Sau khi nhn c thng tin nh tuyn t hng xm, cc Router chy thut

ton nh tuyn to bng nh tuyn. Ri li theo chu k gi bng nhtuyn ca mnh cho cc Router hng xm.

6.2.Link stateThng tin nnh tuyn bao gm Link Trng thi ca linkHot ng :

Cc gi LSA c trao i gia cc Router Cc Router gia trn thng tin thu c t cc LSA xy dng nn

topology ca mng vi chnh n l gc. Cc Router chy thut ton SPF tm ra ng ngn nht c interface

tng ng ti ch Cc Router a thng tin v ng ngn nht v interface tng ng vo

bng nh tuyn Khi 1 Router pht hin ra thay i ca mng. n s gi thng tin update

di dng cc gi LSA n cc Router neighbour vi n. C th tt c ccRouter u nhn c thng tin update. Sau , database ca cc Router s

c update v chy thut ton SPF xy dng li bng nh tuyn

6.3.RIP v RIPngL giao thc thuc loi distance vector

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Hnh 2.24 : Hot ng ca RIPMt s c im ca RIP S dng metric l hop count Maximum hop count = 15

Chu k gi thng tin nh tuyn l 30s C 2 version RIPv1 v RIPv2 . Trong RIPv2 c 1 s ci tin so vi

RIPv1:o C kh nng mang thm 1 s thng tin nh tuyno Cung cp thm kh nng xc thco H tr subnet mask

RIP s dng maximum hop count =15 chng loop. Ngoi ra, cc phngphp khc nh Split horizon, holddown timer c th c cu hnh kmtheo tng kh nng hot ng ca mng

RIPng : da trn Rip trn IPv4, s dng gi tin IPv6 chuyn gi tin.

6.4. OSPF v OSPFngL giao thc nh tuyn theo kiu Link State

6.4.1. Cc loi gi tin trong OSPF trao i thng tin trong OSPF, cc Router s dng cc loi bn tin sau : Hello : thit lp v duy tr thng tin adjacency vi cc neighbour DBD(Database Description Packet) : m t tm tt ni dung c s d liu

link state ca 1 Router OSPF LSR(Link state request) : yu cu 1 phn no ca bng c s d liu

link state ca Router LSU (Link State Update) : gi cc LSA n cc router neighbour LSACK(LSA acknowledge) : xc nhn nhn gi LSA

6.4.2. Cc trng thi ca 1 OSPF interfaceMt interface trong 1 mng s dng OSPF c th trong 1 trong nhng trng

thi sau :

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Down State : ko trao i thng tin Init State : OSPF router gi gi Hello theo chu k 10s thit lp quan h

vi cc Router neighbour. Khi 1 interface nhn c gi tin Hello u tin,n bc vo trng thi Init State chun b thit lp quan h vi Routerneighbour. C 2 kiu quan h l : Two way v Adjacency

Two way State : Khi Router A nhn c gi tin Hello t 1 neighbour RBn gi li gi tin Hello v a thng tin ca RB vo gi tin hello . RBnhn c gi tin hello c tn mnh trong v thit lp quan h Two wayvi RA. trng thi ny cc Router ko trao i thng tin nh tuyn.

ExStart State : trng thi ny, 2 router trao i gi tin DBD Exchange State : Router so snh thng tin m n nhn c t gi DBD

vi thng tin m n c sn. Nu thng tin m n nhn oc cha c trongthng tin ca n c sn, Router s yu cu ton b thng tin tneighbour. Nu thng tin n nhn oc ko c thng tin mi, 2 Router

chuyn sang trng thi Full Adjacency. Loading State : Router s dng gi LSR yu cu thng tin. Khi 1Router nhn oc gi LSR n s gi li gi LSU cha thng tin LSA. GiLSU c xc nhn nhn bng gi LSACK. Sau 2 Router tr FullAdjacency

Full Adjacency :

Hnh 2.25 : S chuyn trng thi v trao i cc gi tin gia 2 interface OSPF

6.4.3. Hot ngBc 1 : Thit lp router adjacency : Cc Router gi gi hello qung co gi

tr Router ID ca mnh cho cc Router khc. Khi n nhn li gi Hello t ccRouter khc, nu n thy ID ca mnh trong gi tin Hello, 2 Router s bc votrng thi Two way.

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Bc 2 : Bnh bu DR v BDR (nu cn thit, ch trong mi trngmultiaccess) DR(Designated Router), BDR(Backup Designated Router)

Trong mi trng multiaccess, c rt nhiu Router cng kt ni vo 1 mng.Nu mi Router u thit lp quan h Full Adjacency vi tt c Router cn li

trao i thng tin link state th s c qu nhiu thng tin nh tuyn trao i trongmng, lng ph bng thng. Do , ta s thit lp mt Router l DR, c quan hFull Adjacency vi tt c cc Router cn li. 1 Router s gi thng tin link saten cho DR. Sau , DR s gi thng tin link state cho ny cho cc Router cn li.

BDR ng vai tr d tr s thay th cho DR khi DR c vn .

Hnh 2.26 : hot ng ca DR v BDRTrong qu trnh bnh bu DR, Router c gi tr Router ID cao nht s tr thnh

DR, Router c gi tr cao th 2 s tr thnh BDR.Bc 3 : Khm ph cc tuyn : cc Router s trao i gi tin DBD, LSR, LSU,

LSACK v thit lp quan h full adjacencyBc 4 : La chn ng ngn nht : sau khi c y thng tin link state, cc

Router chy thut ton SPF tm ra ng ngn nht v interface tng ng ria vo bng nh tuyn

Bc 5 : Duy tr thng tin nh tuyn : OSPF nh k gi gi tin hello ccnh thay i trong mng. Khi c thay i trong mng Roter pht hin thay i sgi gi tin LSU cha thng tin thay i n DR v BDR. DR s gi thng tin nyn cc Router cn li trong mng.

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Hnh 2.27 : S chuyn trng thi ca 1 interface OSPF

6.4.4. OSPFng:OSPFng c nhng im khc so vi OSPF trong IPv4 Cu trc gi tin OSPF c thay i ko cn ph thuc vo i ch IP Bn tin LSA mi c nh ngha mang a chi IP v prefix OSPF chy trn cc link ch ko phi tre mi subnet, mi link c th cha

nhiu subnet Ko cn cung cp c ch xc thc m da vo IPsec thc hin c ch xc

thc

7. Security trong IPv6IPsec Giao thc IPsec c lm vic ti tng Network Layer layer 3 ca m

hnh OSI. Cung cp cc chc nng bo mt cho IPv6. iu ny to ra tnh mmdo cho IPsec hn cc giao thc bo mt hot ng tng trn

IPsec cung cp 3 phng thc bo mt sau cc giao thc cung cp mt m (cryptographic protocols) nhm bo mt gi

tin (packet) trong qu trnh truyn

phng thc xc thc thit lp cc thng s m honhm t c cc mc ch bo mt Authentication : xc nh c ngun gc ca d liu Integrity : m bo d liu ko b thay i trong qu trnh truyn Confidentiality : m bo d liu ko b c hc s dng bi ngi khc

trong qu trnh truyn

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IPsec c thit k cho c IPv4 v IPv6. N ko c s dng trong IPv4 do 1s l do nu trn(IPv4 s dng NAT, ) tuy nhin li tch hp hon ho viIPv6 do s dng cc extension header.

IPsec cung cp cc dch v bo mt M ho qu trnh truyn thng tin m bo tnh nguyn ven ca d liu Phi c xc thc gia cc giao tip Chng qu trnh replay trong cc phin bo mt.

7.1.Cc mode hot ngIPsec c 2 mode hot ng l Transport mode: trong Transport mode, ch nhng d liu bn giao tip

cc gi tin c m ho v/hoc xc thc. Trong qu trnh routing, c IPheader u khng b chnh sa hay m ho; tuy nhin khi authentication

header c s dng, a ch IP khng th bit c, bi cc thng tin bhash (bm). Transport v application layers thng c bo mt bi hmbm (hash), v chng khng th chnh sa (v d nh port number).Transport mode s dng trong tnh hung giao tip host-to-host.

Tunnel mode : trong tunnel mode, ton b gi IP (bao gm c data vheader) s c m ho v xc thc. N phi c ng gi li trong mtdng IP packet khc trong qu trnh routing ca router. Tunnel mode cs dng trong giao tip network-to-network (hay gia cc routers vinhau), hoc host-to-network v host-to-host trn internet.

7.2.Hot ngIPsec cung cp tnh bo mt cho 2 phin bn IP nh s sng 2 header : IP Authentication Header gip m bo tnh ton vn v cung cp xc thc. IP Encapsulating Security Payload cung cp bo mt, v l option bn c

th la chn c tnh nng authentication v Integrity m bo tnh ton vnd liu.

7.2.1. Authentication Header(AH)AH c s dng trong cc kt ni khng c tnh m bo d liu. Hn na

n l la chn nhm chng li cc tn cng replay attack bng cch s dng cng

ngh tn cng sliding windows v discarding older packets. AH bo v qu trnhtruyn d liu khi s dng IP. Trong IPv4, IP header c bao gm TOS, Flags,Fragment Offset, TTL, v Header Checksum. AH thc hin trc tip trong phnu tin ca gi tin IP. di y l m hnh ca AH header.

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Hnh 2.28 : Cu trc AH

7.2.2. Encapsulating Security Payload(ESP)Giao thc ESP cung cp xc thc, ton vn, m bo tnh bo mt cho gi

tin. ESP cng h tr tnh nng cu hnh s dng trong tnh hung ch cn bo mho v ch cn cho authentication, nhng s dng m ho m khng yu cu xc

thc khng m bo tnh bo mt. Khng nh AH, header ca gi tin IP, bao gmcc option khc. ESP thc hin trn top IP s dng giao thc IP v mang s hiu50 v AH mang s hiu 51.

Hnh 2.29 : Cu trc ESP

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Kt lun

Nh vy ta thy c vai tr quan trng ca a ch IP vi cc h thngmng hin nay. Vi s cn kit ca khng gian a ch IPv4, vic chuyn sang a

ch IPv6 l tt yu. Do , trc tin, ta phi nm c nhng kin thc c bn va ch IPv6, c trnh by trong bo co ny. T , c th i vo trin khaicc dch v nh web, mail, DNS trn nn IPv6 cng nh chuyn a ch IPv4sang IPv6. Bo co thc tp ca em cn cnhiu thiu st. Rt mong cc thy cgp sa cha. Em xin chn thnh cm n cc thy c gip em hon thnhbo co thc tp ny.

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Ti liu tham kho

1. Undersatanding IPv6 by Microsoft2. Deploying IPv6 Networks By Ciprian Popoviciu, Eric Levy-Abegnoli,

Patrick Grossetete

3. http://hocit.com/forum/ - ln cui truy cp 10.16am 27/01/20084. http://www.ipv6.org/ - ln cui truy cp 10.16am 27/01/2008
http://www.ipv6.org/http://www.ipv6.org/

thuc tap tong quan ve ipv6 yjpdevqvzm 20130322112350 4

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