Cu 1:

MC LC

3LI NI U

4THUT NG V T VIT TT

5Chng 1: CU TRC A CH IPv4.

51.1. Cu trc a ch IP.

51.1.1. Thnh phn v khun dng ca a ch IP.

61.1.2. nh a ch IP.

91.1.3. a ch mng con v mt n mng con.

91.1.3.1. Phng php phn chia a ch mng con

101.1.3.2. Mt s a ch c bit

111.2. Khun dng ca gi tin IP.

141.3. Gii php nh tuyn theo a ch IP.

141.3.1. Cc phn t c bn ca mt h thng nh tuyn.

151.3.2. X l gi tin b nh tuyn.

161.3.3. X l gi tin khi ti ch.

161.3.4. nh tuyn trn mng Internet (IP Routing).

171.4. Kt lun.

19Chng 2: CU TRC A CH IPv6.

192.1. c im ca IPv6.

192.1.1. Kiu nh dng tiu mi.

192.1.2. Khng gian a ch m rng.

202.1.3. C s h tng nh tuyn v nh a ch phn cp v hiu qu.

202.1.4. Cu hnh a ch Stateful v Stateless.

202.1.5. Bo mt.

202.1.6. H tr tt hn cho QoS.

202.1.7. Giao thc mi cho s tng tc Node lng ging.

212.1.8. C kh nng m rng.

212.2. S khc bit gia IPv4 v IPv6.

222.3. nh a ch IPv6.

222.3.1. Khng gian a ch IPv6.

232.3.2. C php a ch IPv6.

242.3.3. Prefix ca IPv6.

242.3.4. Cc dng a ch IPv6.

292.3.5. S tng thch a ch.

312.3.6. a ch IPv4 v s tng ng IPv6

322.4. Khun dng ca gi tin IPv6.

322.4.1. Khun dng gi tin IPv6.

332.4.2. So snh khun dng IPv4 v IPv6.

342.4.3. Cc tiu m rng ca IPv6.

352.5. Kt Lun.

36Chng 3: TRIN KHAI MNG IPv6

363.1. Trin khai mng IPv6 trn nn IPv4.

363.1.1. Cc vn chung.

363.1.2. Mc ch.

373.2. Cc c ch chuyn i.

383.2.1. Lp IP song song ( Dual IP layer).

393.2.2. ng hm IPv6 qua IPv4.

413.2.3. 6to4.

423.3. Kt Lun

43KT LUN

44TI LIU THAM KHO

LI NI U

Nh chng ta bit Internet l mt mng my tnh ton cu, do hng nghn mng my tnh t khp mi ni ni li to nn. Trn ta c th tm hiu mi th t vn hc, ngh thut, lch s, khoa hc, v..v... khi no chng ta t hi v sao ta ch cn ngi nh click chut l c th tm thy mi th, cc ti liu y t u ra v lm th no ta c th lin kt c vi chng. Cu tr li tht n gin, mi mt trang web cha thng tin u c mt a ch Internet cc trang web khc c th tm n chng. Vy a ch Internet l g? Cu trc ra sao v n lm vic th no?

Cc mng my tnh d nh d to khi ni vo Internet u bnh ng vi nhau. Do cch t chc nh vy nn trn Internet c cu trc a ch, cch nh a ch c bit. Mi khch hng hay mt my ch (Host) hoc B nh tuyn u c mt a ch Internet duy nht m khng c php trng vi bt k ai. Do vy m a ch Internet thc s l mt ti nguyn. a ch khng c trng nhau cn phi c mt cu trc a ch c bit qun l thng nht v mt t chc Internet gi l Trung tm thng tin mng Internet- Network Information Center (NIC) ch tr phn phi, NIC ch phn a ch mng (Net ID) cn a ch my ch trn mng (Host ID) do cc t chc qun l Internet ca tng quc gia phn phi.

Trong bi tiu lun ny cp n mt s vn cn nghin cu: a ch IPv4/IPv6, cu trc, phng php nh a ch, cch thc s dng trn Internet. Cch thc v cc vn trin khai IPv6 - IPv4 nh th no.

B cc bi tiu lun c chia ra lm 3 chng:

Chng 1: Cu trc a ch IPv4.

Chng 2: Cu trc a ch IPv6.

Chng 3: Trin khai mng IPv6.

THUT NG V T VIT TTVit ttCh gii ting AnhCh gii ting Vit

DNSDomain Name SystemH thng tn min.

DHCPDynamic Host Configuration ProtocolGiao thc cu hnh a ch ng.

ARPAddress Resolution ProtocolGiao thc phn gii a ch.

ICMPInternet Control Message ProtocolGiao thc thng ip iu khin.

IGMPInternet Group Management ProtocolGiao thc Internet cac host kt ni, huy kt ni t cac nhom multicast.

IPSecIP SecurityMt cng ngh cung cp bo mt.

MTUMaximum Transmission Unitn v truyn ti a.

QoSQuality of ServiceCht lng dch v.

TCP/IPTransmission Control Protocol/IPGiao thc dung cho qua trinh truyn va sa li i vi cac d liu.

IPv4Internet Protocol Version 4Phin bn 4 ca giao thc Internet.

IPv6Internet Protocol Version 6Phin bn 6 ca giao thc Internet.

Tunnelng hm.

RFCRequest For CommentsTi liu chun cho Internet

6BoneMng th nghim v IPv6.

BGPBorder Gateway ProtocolGiao thc cng bin

NATNetwork Address TranslationCng ngh thay th a ch

ISPInternet Service ProviderCung cp dch v Internet

Chng 1: CU TRC A CH IPv4.

1.1. Cu trc a ch IP.

1.1.1. Thnh phn v khun dng ca a ch IP.

a 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 t bit 1 cho n bit 32. Cc Octet cch bit nhau bng mt du chm (.).

Hnh 1.1: Khun dng tiu a ch IPv4

* a ch biu hin dng bit nh phn:

xyxyxyxy. xyxyxyxy. xyxyxyxy. xyxyxyxy

x, y = 0 hoc 1.

* a ch biu hin dng thp phn: xxx.xxx.xxx.xxx

V d:

146.123.110.224

Dng vit y ca a ch IP l 3 con s trong tng Octet.

a ch IP thng thy trn thc t c th l 53.143.10.2 nhng dng y l: 053.143.010.002

* Bao gm c 3 thnh phn chnh. Bit 1..32

- Bit nhn dng lp (Class bit), phn bit a ch lp no.- a ch ca mng ( Net ID).

- a ch ca my ch ( Host ID).

Ghi ch: Tn l a ch my ch nhng thc t khng ch c my ch m tt c cc trm lm vic, cc cng truy nhp, v..v.. u cn c a ch nhn dng.

1.1.2. nh a ch IP.

Mt b nh tuyn s dng a ch IP chuyn tip gi tin t mng ngun ti mng ch. Gi tin phi ch ra c a ch mng ngun v mng ch. Khi mt gi c nhn ti b nh tuyn, n s xc nh a ch mng ch v xc nh ng i ca gi tin v chuyn tip gi tin qua cng tng ng. Mi a ch Ip cng gm c 2 phn: nhn dng a ch mng- ch ra mng, v nhn dng a ch host - ch ra host. Mi octet u c th chia thnh nhng nhm a ch mng khc nhau, qu trnh chia a ch c th c thc hin theo m hnh phn cp.

Hnh 1.2: M hnh phn cp a chCc a ch c thc hin theo m hnh phn cp bi n cha nhiu mc khc nhau. Mt a ch IP thc hin 2 ch s v a ch mng v a ch host trong cng mt a ch. a ch ny phi l duy nht, bi khi thc hin mt a ch trng lp s dn n nhng vn v nh tuyn. Phn u l a ch mng (hay a ch ca h thng), phn th 2 l a ch host trong mng.

a ch IP c chia thnh cc lp, A, B, C, D, E. Hin ti dng ht lp A, B v gn ht lp C, cn lp D v E T chc Internet ang dnh cho mc ch khc khng phn, nn chng ta ch nghin cu 3 lp u.

Hnh 1.3: Cu trc cc lp a ch IPQua cu trc cc lp a ch IP chng ta c nhn xt sau:

- Bit nhn dng l nhng bit u tin: ca lp A l 0, ca lp B l 10, ca lp C l 110.

- Lp D c 4 bit u tin nhn dng l 1110, cn lp E c 5 bit u tin nhn dng l 11110.

- a ch lp A: a ch mng t v a ch my ch trn tng mng nhiu.

- a ch lp B: a ch mng va phi v a ch my ch trn tng mng va phi.- a ch lp C: a ch mng nhiu v a ch my ch trn tng mng t.

thc hin nhng mng vi quy m khc nhau, trc ht ta phi hiu c c ch phn lp trong mng, a ch IP c chia thnh nhng nhm c gi l nhng lp. Cc nhm ban u c gi l a ch phn lp y . Mi a ch IP bao gm 32 bit c chia thnh 4 phn, mi phn 8 bit v s th t ca cc bit s dng cho vic xc nh a ch mng v a ch host ty theo lp m n thuc v.

Lp A thc hin trong nhng mng ln c kh nng h tr trn 16 triu my. Ch bao gm octet u tin c s dng ch ra a ch mng, 3 octet cn li s dng xc nh a ch ca host trong mng.

Bit u tin ca lp A lun bng 0. s thp nht ca octet u tin c th th hin l 0, v gi tr ln nht l 127. Tuy nhin gi tr 0 v 127 ca octet u tin khng c s dng trong vic nh a ch mng, do tt c cc a ch mng ca lp A s thc hin gi tr t 1 ti 126 ca octet u tin.

a ch lp B c thit k h tr nhng nhu cu cho nhng mng ln. a ch lp B s dng 2 trong s 4 octet u tin lm a ch mng, 2 octet cn li c s dng ch ra a ch host.

Hai bit u tin ca octet u tin ca mt a ch thuc v lp B lun l 10, 6 bit cn li ca octet u tin c th thay i l 0 hoc 1. Do gi tr nh nht ca octet u tin ca mt a ch lp B s l 10000000 = 128, gi tr ln nht s l 10111111 = 191. Bt c a ch no c gi tr ca octet u tin nm trong khong t 128 191 u l nhng a ch mng ca lp B.

a ch lp C cng c quy lut tng t c thc hin, gi tr 3 bit u tin ca mt a ch lp C lun l 110. Do gi tr nh nht ca octet u tin ca mt a ch lp C c th l 11000000 = 192, gi tr ln nht l 11011111 = 223. Nu mt a ch mng c gi tr ca octet u tin ri vo trong khong 191 223 th l mt a ch IP thuc lp C. Lp C thc hin 3 octet l a ch mng cn 1 octet cn li c s dng lm a ch host. N c kh nng h tr 254 a ch host cho mi mng thuc v lp C.

a ch lp D c to ra to kh nng v a ch multicast. Mt a ch IP multicast l mt a ch c kh nng thc hin vic truyn thng tin ti mt nhm cc my trm vi a ch IP unicast. Do , mt my trm khi s dng a ch multicast c kh nng truyn ng thi mt gi tin ti nhiu ngi nhn.

Bn bit u tin ca mt a ch IP ca lp D lun l 1110. Do octet u tin ca mt a ch mng thuc v lp C c gi tr nh nht l: 11100000 = 224 v gi tr ln nht s l 11101111 = 239.

a ch lp E thc hin trong phng th nghim phc v mc ch nghin cu. Bn bit u tin ca mt a ch ca lp E l 1111. Do khong gi tr ca octet u tin ca mt a ch lp E s l: 240 255. 1.1.3. a ch mng con v mt n mng con. 1.1.3.1. Phng php phn chia a ch mng con

Trc khi nghin cu vn ny chng ta cn phi hiu qua mt s khi nim lin quan ti vic phn a ch cc mng con.

1/ Mt n mc nh: ( Default Mask) c nh ngha trc cho tng lp a ch A,B,C. Thc cht l gi tr thp phn cao nht ( khi tt c 8 bit u bng 1) trong cc Octet dnh cho a ch mng Net ID.

Mt n mc nh: Lp A: 255.0.0.0

Lp B: 255.255.0.0

Lp C: 255.255.255.0

2/ Mt n mng con: ( Subnet Mask)

Mt n mng con l kt hp ca Mt n mc nh vi gi tr thp phn cao nht ca cc bit ly t cc Octet ca a ch my ch sang phn a ch mng to a ch mng con.

Mt n mng con bao gi cng i km vi a ch mng tiu chun cho ngi c bit a ch mng tiu chun ny dng c cho 254 my ch hay chia ra thnh cc mng con. Mt khc n cn gip b nh tuyn trong vic nh tuyn cuc gi.

Nguyn tc chung

- Ly bt mt s bit ca phn a ch my ch to a ch mng con.

- Ly i bao nhiu bit ph thuc vo s mng con cn thit m nh khai thc mng quyt nh s tao ra.

1.1.3.2. Mt s a ch c bit

- a ch mng IP l a ch IP m tt c cc bit thuc phn nh danh my ( host ID) = 0.

- a ch qung b ti tt c cc my trong mng LAN.

VD: 255.255.255.255

- a ch tt c cc my ca mng X.Y.Z xa.

VD: X.Y.Z.255

- a ch Loopback c s 127 u 127.X.Y.Z

Mc ch th ti ch cc phn mm IP.

- a ch 0.0.0.0 dng ch mng ny.

a ch 0.0.0.5 dng ch my s 5 mng ny (mng ang ci t).

-a ch mng s dng cho mng ring (mng ni b, khng s dng lm a ch internet)

+ Lp A: 10.0.0.0

+ Lp B: 172.16.0.0 to 172.31.255.255

+ Lp C: 192.168.0.0 to 192.168.255.2551.2. Khun dng ca gi tin IP.

Hnh 1.4: Khun dng ca gi tin IPv4 Version IP-V4: Khi gi tin ti b nh tuyn, b nh tuyn s phn tch nu thy phin bn c hn th b nh tuyn s hy b gi tin v thng bo cho trm ngun bit.

Header length: di ca gi tin tnh theo n v 32 bit.

Type of service:

Kiu dch v c s dng trong tiu gi tin IP ch ra quan h u tin cho vic chuyn cc gi tin, thng thng cc gi tin IP c x l theo nguyn tc FIFO, cc bit 0,1,1 trong trng kiu dch v ch ra cc thng tin v tr, thng lng v tin cy. Thng thng 2 trong s 3 thng tin s c t, nhng trng chc nng ny khng buc tt c cc b nh tuyn phi x l.

- D ( Delay): tr

D=0: yu cu truyn tr bnh thng.

D=1: yu cu tr thp.

- T ( Throughput): thng lng

T=0: thng lng bnh thng.

T=1: thng lng cao.

- R ( Reliability): tin cy

R=0: tin cy bnh thng.

R=1: tin cy cao.

Total length: di ton b ca gi tin Max 216=64 KB, thng thng ngn hn.

ID: s nh danh ca gi tin. Nu 1 gi tin phi phn thnh nhiu mnh truyn i th tt c cc mnh phi c cng nh danh. Flag: 1 bit d tr

DF (dont Fragment)

DF=1: khng c php phn gi tin thnh mnh tin.

DF=0: cho php phn mnh truyn.MF (More Fragment)

MF=1: cho bit cn c cc mnh tin tip theo thuc cng mt gi tin.

MF=0: y l mnh tin cui cng ca gi tin hoc gi tin khng phn mnh.

Offset: Cho bit v tr ca mnh tin trong gi tin, n v tnh l 8 byte. Ti tram thu, 3 trng (5), (6), (7) cho php ghp cc mnh tin thnh gi tin.

VD: gi tin 3000 byte m B nh tuyn ch chuyn gi tin 1000byte mt ln th phi phn mnh tin. ID

DF

MF

offset400

0

1

0

400

0

1

125

400

0

0

250

Ghi ch : Trong trng hp truyn khng phn mnh th khng cn cc thng tin nhng gi tin vn phi cha thm 32 bit ny. Giao thc Internet phin bn 6 (IPv6) s khc phc iu ny.

Time to live (TTL): Thi gian sng ca gi tin. Trng ny c 8bit ban u tnh n v l giy, vy thi gian gi tin c php tn ti trn mng l:

28=256 giy > 4 pht

Trong thc t trng ny cha s bc nhy chnh l s b nh tuyn m gi tin c php i qua. C mi ln gi tin qua mt b nh tuyn th TTL s tr i 1 v khi bng 0 th gi tin s b hy v thng bo cho trm ngun. y l gii php iu khin tc nghn.

Protocol: Cho bit giao thc c s dng tng trn.

- Nu tng giao vn l TCP th c m l 6.

- Nu tng giao vn l UDP th c m l 17.- Nu l ICMP th c m l 1.

Heder checksum: Kim tra li cho u gi tin. Soure Address: a ch ngun.

Destination Address: a ch ch.

Cc a ch ny c dng nh ng trn mng Internet nn cn gi l IP address. a ch di 32 bit c chia thnh 4 byte, mi byte c th hin bng mt s thp phn v cch nhau bi du chm.

Option: La chn.

- Record Route: ghi li a ch ca tt c cc b nh tuyn m gi tin i qua. di ca trng la chn ny do trm ngun quy nh. Nu s b nh tuyn m gi tin i qua qu nhiu th a ch ca cc b nh tuyn sau s khng c ghi vo gi tin.

- Time Stamp (nhn thi gian): ghi li thi gian m gi tin i qua b nh tuyn. C 3 cch ghi.

. Khi gi tin i qua b nh tuyn, ghi li danh sch thi gian gi tin qua b nh tuyn. . Ghi a ch IP v thi gian tng ng khi gi tin i qua.

. Trm ngun s ghi sn mt s a ch cn o thi gian v gi tin ti b nh tuyn c a ch tng ng th s c ghi thi gian vo.1.3. Gii php nh tuyn theo a ch IP.

1.3.1. Cc phn t c bn ca mt h thng nh tuyn.B nh tuyn l mt thit b lp 3 trong m hnh OSI 7 lp. N c hai chc nng c bn l nh tuyn v chuyn mch gi tin IP t u vo n u ra. Qu trnh nh tuyn l qu trnh tp hp cc thng tin v cu trc topo mng nhm to ra mt bng nh tuyn. Qu trnh chuyn mch gi tin l sao chp mt gi t mt giao din u vo ti mt giao din u ra thch hp da trn thng tin cha trong bng chuyn tip gi. Bt k h thng nh tuyn no u cn 4 phn t c bn thc hin qu trnh nh tuyn v chuyn mch gi tin l:

Cc phn mm nh tuyn. B phn x l gi. Mt ma trn chuyn mch. Card ng truyn.

Bn phn t c bn ny cu thnh mt b nh tuyn theo cu trc nh sau:

B x l chnh thi hnh phn mm nh tuyn, phn mm nh tuyn ny thc hin cc chc nng nh tuyn v duy tr cc thng tin v cu trc mng Internet thng qua cc giao thc nh tuyn. Ma trn chuyn mch thc hin hot ng chuyn mch gi tin bng cch s dng b x l gi, b x l ny thng l mt ASIC ( Application Specific Intergrated Circuit-Mch tch hp c trng cho ng dng) c ti u thc hin nhim v c th vi tc cao. im ny th n ph hp vi b nh tuyn trn ng trc hin nay. Ngoi ra b nh tuyn thng xuyn duy tr mt bng khc gi l bng chuyn gi, bng ny c trong cc b my chuyn tip gi ( FE-Forwarding Engine). FE thc hin vic c a ch ch t tiu gi n, thc hin vic tm kim tuyn, tm tin t ph hp di nht ( Longest Prefix Matching) v chuyn gi n giao din u ra c xc nh. V c bn th bng chuyn gi bt ngun t bng nh tuyn nhng n t c cp nht hn. Bng nh tuyn c duy tr bi phn mm nh tuyn, phn mm ny thc hin qu trnh x l tng i chm trong khi cp nht bng v khi bng c cp nht, bn sao ca n s c chuyn n b my chuyn gi. Bn sao ny c th l mt tp hp con ca ton b bng nh tuyn v c th c bin i ph hp vi phin bn nh hn. Ma trn chuyn mch l thnh phn ct yu ca mt b my chuyn gi. V bn cht, mt b nh tuyn bao gm phng tin nh tuyn c thc hin trong phn mm v s dng CPU chnh ca b nh tuyn tin hnh hot ng phc tp hn nh thc hin cc giao thc nh tuyn, cc c im k thut lu lng, m bo QoS, bin i tiu gi trc khi truyn i v cc c im da trn cc phn mm khc ca b nh tuyn. Ngoi ra, FE cn tin hnh cc nhim v n gin hn ti tc cao. 1.3.2. X l gi tin b nh tuyn.Cc gi tin b nh tuyn cn c vo b m ca b nh tuyn v cc thng s phn tiu ca gi IP a ra cc quyt nh ph hp vi gi tin. Kim tra gi tin IP

- Header checksum nu c li th b nh tuyn hy gi tin.

- Kim tra 1 s thng s : Version, Header length, Total length, Protocol nu sai hy b gi tin.

- Kim tra xem nu TTL=0 th hy gi tin.

- Nu b m ca b nh tuyn y khng cha c gi tin th hy gi tin.

Chun b truyn :

- Phn tch trng (Type of service) tm ra ng i tng ng. - Xc nh gi tin c phn mnh khng?

+ Nu phn mnh th thc hin chia gi tin.

+ Nu khng c phn mnh nhng b nh tuyn li khng c kh nng truyn c gi tin th s hi cc b nh tuyn lng ging v nh b nh tuyn lng ging chuyn gi tin. Nu khng c b nh tuyn lng ging no chuyn c gi tin th b nh tuyn s hy gi tin v thng bo cho trm ngun.

Tnh ton li mt s thng s ca gi tin: - TTL - 1 (khi qua 1 b nh tuyn).

- in cc thng s cho trng hp phn mnh .

- in cc thng s cho trng la chn (Option).

- Tnh li Header checksum. 1.3.3. X l gi tin khi ti ch. Kim tra gi tin IP.- Header checksum: Nu c li th my ch hy gi tin.

- Kim tra 1 s thng s: Version, Header length, Total length, Protocol nu sai hy b gi tin.

- Kim tra xem nu TTL=0 th hy gi tin.

- Nu b m ca b nh tuyn y khng cha c gi tin th hy gi tin.

Chun b

- Khng kim tra Type of service v y l trm ch nn khng cn chuyn n trm khc.

- Kim tra xem gi tin c phn mnh?

Khi nhn c mnh tin u tin ca gi tin phn mnh, trm ch s khi ng mt ng h thi gian, nu ht thi gian quy nh m mnh tin cui cng cha n th trm ch s hy b tt c cc mnh tin nhn. Nu cc mnh tin n ng gi th trm ch s ghp cc mnh tin thnh gi tin gc. Chuyn gi tin ln tng trn x l tip. 1.3.4. nh tuyn trn mng Internet (IP Routing).

1.3.3.1. Bng tm ng.

1.3.3.2. Giao thc tm ng (IP Protocol).

Chc nng ca giao thc tm ng

- Thit lp bng tm ng. - Cp nht bng tm ng.

- Tnh ton qung ng i ngn nht chn a ch ca b nh tuyn tip theo nhm chuyn gi tin i nhanh nht.

Giao thc tm ng n gin l giao thc da vo topo mng lp bng tm ng bng tay v cp nht bng tay nhm tm ng ngn nht. Giao thc ny ch s dng cho mng n gin.

Giao thc tm ng trn Internet, s dng trong mng phc tp.

- Cp nht t ng.

- T ng tnh ton tm ra b nh tuyn tip theo da trn hin trng ca mng.

Tiu chun nh gi giao thc tm ng:

+ Thch nghi rt nhanh vi thay i ca mng. + Tnh c con ng ti u.

+ D dng nng cp khi mng pht trin.

+ Tit kim ti nguyn ca my.

+ Bng thng tit kim nht.

1.3.3.3. S o c s dng trong Internet. S o c tnh nh sau:

- S bc nhy m gi tin i qua.

- S bc nhy m gi tin i qua nhng c trng s.

- Tng hp t nhiu thng s nh bng thng, tr, ti hin ti, gi thnh....

- Thut ton da trn s o tnh ng i ngn nht gi l DVA ( Distance Vector Algorithm). Giao thc RIP s dng thut ton DVA.

- Thut ton trng thi lin kt gi l LSA ( Link State Algorithm). Giao thc OSPF s dng thut ton LSA.1.4. Kt lun.

Trong chng ny, bi tiu lun cp ti cu trc a ch IPv4. a ch IPv4 c hai chc nng c bn: a ch cc giao din mng ( cung cp mt a ch duy nht cho nhng giao din khi tham gia vo mng Internet), h tr cho nh tuyn ( truyn ti thng tin t mng ny sang mng khc). Chng tip theo s trnh by v a ch Internet phin bn 6 - IPv6, y l phin bn c thit k nhm khc phc nhng hn ch ca giao thc Internet IPv4.

Chng 2: CU TRC A CH IPv6. 2.1. c im ca IPv6.Giao thc Internet phin bn 4 ( IPv4) tuy ang c s dng rng ri hin nay nhng c mt s nhc im :

+ a ch Ip c 32 bit, cho ti nay gn cn kit, cn phi c m rng .

+ Phn u ( phn tiu ) ca khun dng gi tin IPv4 c nhng thng tin d tha.

+ An ninh thng tin cha tht m bo, cn thiu.

+ Cha h tr tt cho vic truyn thng a phng tin ( multimedia).

S ra i ca IPv6 s khc phc nhng nhc im trn.

- nh dng Tiu mi.

- Khng gian a ch rng.

- C s h tng nh tuyn v nh a ch phn cp v hiu qu.- Cu hnh a ch Stateful v Stateless.- Bo mt.- H tr tt hn cho QoS.- Giao thc mi cho s tng tc node lng ging.- C kh nng m rng. 2.1.1. Kiu nh dng tiu mi.- Tiu ca IPv6 c mt kiu nh dng mi c thit k gi cho tiu bn trn mc ti thiu. iu ny t c bng cch chuyn c cc trng hp khng cn thit v cc trng la chn sang phn tiu m rng, phn m rng ny i theo sau phn tiu ca IPv6. Tiu IPv6 c t chc tt, x l hiu qu hn ti cc b nh tuyn trung gian.

- Cc tiu IPv4 v IPv6 l khng gn lin. IPv6 khng phi l siu tp ca chc nng m tng thch ngc vi IPv4. Mt host hoc mt b nh tuyn phi dng mt s b sung ca IPv4 v IPv6 nhn ra v x l c 2 kiu nh dng tiu . Tiu IPv6 mi ch rng gp 2 ln IPv4 mc d a ch IPv6 rng gp 4 ln IPv4. 2.1.2. Khng gian a ch m rng.- IPv6 c a ch IP di 128 bit. Mc d 128 bit c th biu din hn 3.4x1038 t hp, khng gian a ch rng ca IPv6 c thit k cho php nhiu mc subneting v chia vng i ch t a ch gc Internet n cc mng ring trong cng 1 t chc.

- Mc d ch mt s lng nh a ch hin ti c chia phn cho host, vn cn nhiu a ch cho tng lai. Vi mt s lng a ch ln nh vy th cc k thut tit kim a ch nh NAT l khng cn thit na. 2.1.3. C s h tng nh tuyn v nh a ch phn cp v hiu qu.

- Cc a ch IPv6 ton cu c dng trong phn IPv6 ca Internet c thit k to mt c s h tng nh tuyn c th tm tt, phn cp v hiu qu. C s h tng ny c da trn s trin khai chung nhiu cp ca cc nh cung cp dch v ISP. 2.1.4. Cu hnh a ch Stateful v Stateless.

- n gin ha cu hnh host, IPv6 h tr c hai kiu cu hnh l stateful, nh l cu hnh a ch trong s c mt ca mt DHCP server v stateless ( cu hnh a ch trong khng c mt ca mt DHCP). Vi kiu cu hnh a ch stateless th cc host trn mt lin kt s t ng cu hnh vi a ch IPv6 cho lin kt ( c gi l a ch lin kt ni b) v vi cc a ch c phn pht t Prefixes qung co bi cc b nh tuyn ni b. Ngay c khi khng c cc b nh tuyn th cc host trn cng mt lin kt vn c th t ng cu hnh vi cc i ch lin kt ni b v lin lc vi nhau m khng cn cu hnh nhn cng. 2.1.5. Bo mt.

- Trong hot ng Internet, bo mt ti tng IP c thc hin ph bin bng cng ngh IPSec. IPSec thc hin chc nng xc nh ni gi v m ha ng kt ni, do vy m bo c kt ni bo mt. Cng ngh IPSec h tr c a ch IPv4 v IPv6. Tuy nhin trong IPv6, IPSec c nh ngha nh l mt c tnh bt buc ca a ch IPv6 khi cc th tc bo mt ca IPSec c a vo thnh hai c tnh l hai tiu m rng ca a ch IPv6. l tiu Xc thc, v tiu M ha. 2.1.6. H tr tt hn cho QoS.- Cc trng mi trong tiu ca IPv6 nh ngha cch thc m lu lng qun l v nhn dng. S nhn dng lu lng dng mt trng nhn lu lng trong tiu IPv6 cho php cc b nh tuyn nhn dng v cung cp vic qun l c bit cho cc gi thuc cng mt lung, mt seri cc gi gia ngun v ch. Bi v lu lng c nhn dng trong tiu IPv6, vic h tr QoS c th t c ngay c khi trng ti ca gi c m ha thng qua IPSec. 2.1.7. Giao thc mi cho s tng tc Node lng ging.

- Giao thc tm kim lng ging cho IPv6 l mt seri ca ICMP cho cc bn tin ca IPv6, chng qun l vic tng tc gia cc node lng ging. Tm kim lng ging thay th cho cc bn tin giao thc ARP da vo vic broadcast, cc bn tin ICMPv4 b nh tuyn tm kim v multicast hiu qu. 2.1.8. C kh nng m rng.

IPv6 c th d dng c m rng cho cc tnh nng mi bng cch thm vo cc tiu m rng vo sau tiu ca IPv6. Khng ging nh cc la chn ca tiu IPv4 ch c th h tr 40 byte option, kch thc ca tiu m rng ca IPv6 khng ch bi kch thc ca gi IPv6.2.2. S khc bit gia IPv4 v IPv6. IPv4IPv6

Dng a ch 32 bitDng a ch 128 bit

IPSec l ty chn

Khng c xc nhn lung gi cho vic qun l QoS bi cc b nh tuyn trong phn tiu Vic xc nhn lung gi cho qun l QoS bi cc b nh tuyn c dng trong trng nhn lung.

Phn mnh c thc hin bi host v b nh tuynPhn mnh ch thc hin bi host gi

Tiu bao gm c phn checksumTiu khng bao gm phn checksum

Tiu c phn ty chnTt c d liu ty chn c chuyn sang phn tiu m rng.

ARP dng broadcast ARP Request frames chuyn mt a ch IPv4 sang a ch MACARP Request frames thay th bng cc bn tin Neighbor Solicitation multicast

IGMP c dng qun l cc local subnet group membership.IGMP c thay th bi cc bn tin Multicast Listener Discovery (MLD).

ICMP b nh tuyn tm kim c dng xc nh ia ch IPv4 default gateway tt nht v y l mt ty chnICMP b nh tuyn tm kim c thay bng cc bn tin ICMPv6 b nh tuyn Solicitation v b nh tuyn qung co v y l 1 yu cu.

Phi c cu hnh nhn cng hoc thng qua DHCPKhng yu cu cu hnh nhn cng hoc thng qua DHCP

Dng cc bng ghi ti nguyn trong min DNS nh x a ch IPv4 sang tn hostDng cc bng ghi ti nguyn con tr trong min DNS nh x a ch IPv6 sang tn host

Phi h tr mt kch thc gi l 576 byte ( c th c phn mnh)Phi h tr mt kch thc gi l 128 byte ( khng phn mnh)

Dng cc bng ghi ti nguyn a ch host trong DNS nh x tn host sang IPv4Dng cc bng ghi ti nguyn a ch host trong DNS nh x tn host sang IPv6

a ch broadcast c dng gi thng tin ti tt c cc node trn cng mt subnetKhng c a ch broadcast. Thay vo l a ch link-local scope all-node multicast

Bng 2.1: S khc bit gia IPv4 v IPv6. 2.3. nh a ch IPv6. 2.3.1. Khng gian a ch IPv6.- Kch thc a ch IPv6 l 128 bit, rng gp 4 ln a ch ca IPv4. Khng gian a ch 32 bit cho php 232 hay 4.294.967.296 a ch. Khng gian a ch 128 bit cho php 2128 a ch hay 340.282.366.920.938.463.463.374.607.431.768.211.456 (3.4x1038) a ch.

- Vo nhng nm cui thp nin 70 ca th k trc khi m khng gian a ch IPv4 c thit k th ngi ta cha tng tng c rng n s cn kit trong tng lai. Tuy nhin do c nhiu s thay i trong k thut v thc t phn vng khng thy trc c s bng n ca cc host trn Internet v khng gian a ch IPv4 c phn pht ht vo nm 1992, do cn 1 khng gian a ch mi thay th..

- Vi IPv6 tht kh c th tng tng c rng n s c phn pht ht bi v theo c tnh khng gian a ch IPv6 s cung cp cho mi m2 b mt tri t l 655.570.793.348.866.943.898.599 ( 6.5x1023) a ch. Kch thc tng i ln ca a ch IPv6 c thit k chia nh thnh cc min nh tuyn phn cp phn nh topo ca Internet hin nay. Vic s dng 128 bit cho php nhiu mc phn cp v tnh linh ng trong vic thit k nh tuyn v nh a ch phn cp. 2.3.2. C php a ch IPv6.- a ch IPv6 128 bit c chia thnh 8 khi mi khi 16 bit, mi khi ny c chuyn sang dng s hexa 4 bit v c phn bit vi nhau bng du hai chm.

V d : cho 1 a ch IPv6 di dng nh phn nh sau:00100001110110100000000011010011000000000000000000101111001110110000001010101010000000001111111111111110001010001001110001011010 a ch ny c chia ra thnh cc khi 16bit nh sau: 0010000111011010 0000000011010011 0000000000000000 0010111100111011 0000001010101010 0000000011111111 1111111000101000 1001110001011010. Mi khi ny c chuyn sang ch s hexa v chia cch nhau bng du hai chm, kt qu l: 21DA:00D3:0000:2F3B:02AA:00FF:FE28:9C5A

- Vic vit a ch IPv6 c th n gin ha bng cch xa b 0 ng u trong mi khi 16 bit. Tuy nhin mi khi phi c t nht mt s n. Trong v d trn, a ch trn c n gin ha thnh: 21DA:D3:0:2F3B:2AA:FF:FE28:9C5A

Nn cc ch s 0

- Mt s loi a ch cha cc chui di cc s 0. n gin ha trong cch vit, mt chui lin tip cc khi 16 bit c gi tr 0 trong kiu nh dng theo s hexa phn cch nhau bng du : c nn thnh :: v c gi l du hai chm kp. V d: a ch link-local FE80:0:0:0:2AA:FF:FE9A:4CA2 c nn thnh FE80::2AA:FF:FE9A:4CA2, v a ch multicast FF02:0:0:0:0:0:0:2 nn thnh FF02::2.

-Vic nn 0 ch c th c dng nn mt chui cc khi 16 bit lin tip n m thi. Ta khng th nn 0 vi cc s 0 l mt phn ca khi 16 bit. V d nh ta khng th nn a ch FF02:30:0:0:0:0:0:5 thnh FF02:3::5, m ta ch c th nn thnh FF02:30::5.

xc nh c bao nhiu con s 0 ng gia :: th ta c cng thc sau: N= ( 8-n)*16 trong n l s khi bit 16 bit a ch cn li c biu din dng s hexa. - Vic nn 0 ch c dng 1 ln i vi 1 a ch cho trc, nu khng th ta s khng th xc nh c con s khng c gin lc. 2.3.3. Prefix ca IPv6.- Prefix l mt phn ca a ch IPv6, n ch ra cc bit c gi tr c nh hoc l cc bit ng vai tr l ID ca mng. Cc prefix cho nh danh mng con ca IPv6, cc tuyn, cc vng a ch c biu din nh trong k hiu CIDR ( classless Inter-Domain Routing) cho IPv4. V d 21DA::/48 cho mt a ch Prefix tuyn v 21DA:D3:0:2F3B::/64 cho 1 prefix mng con. Trong IPv6 ch dng prefix ch khng dng mt n mng con nh IPv4. 2.3.4. Cc dng a ch IPv6. a ch unicast.Mt a ch unicast xc nh mt giao din n trong phm vi ca loi a ch unicast. Vi mt topology nh tuyn unicast thch hp, cc gi c nh a ch unicast c chuyn n mt giao din n.

a ch multicast.Mt a ch multicast xc nh nhiu giao din. Vi topo nh tuyn thch hp th cc gi c nh a ch multicast s c chuyn ti tt c cc giao din m c xc nh bi a ch ny. Mt a ch multicast c dng trong truyn thng mt-nhiu, c chuyn n nhiu giao din.

a ch anycast.Mt a ch Anycast xc nh nhiu giao din. Vi topology nh tuyn thch hp th cc gi c nh a ch anycast c chuyn n mt giao din n gn nht c xc nh bi a ch anycast ny. Khi nim giao din gn nht c xc nh gn nht trong gii hn khong cch nh tuyn. a ch anycast c dng trong truyn thng 1-1 trong nhiu.

2.3.4.1. a ch unicast IPv6.a ch unicast IPv6 bao gm cc loi sau: a ch unicast ton cu, a ch link-local, a ch site-local v a ch c bit.

a ch Unicast ton cu

a ch Unicast ton cu tng ng vi a ch public ca IPv4. N c th nh tuyn ton cu trong Internet. Khng ging nh Internet da trn IPv4 c s nh tuyn trn c dng phng v phn phn cp Internet IPv6 c thit k t nn mng ca n l h tr cho vic nh tuyn v nh a ch phn cp v hiu qu.

Cc trng ca a ch Unicast ton cu c m t nh sau:

Phn c nh c gn cho gi tr l 001.

Prefix nh tuyn ton cu: ch prefix nh tuyn ton cu cho mt site ca mt t chc c th. Ba bit c nh cng vi 45 bit prefix nh tuyn ton cu to thnh mt prefic site 48 bit, prefix ny c cp cho mt site c nhn ca mt t chc. Mt khi c cp cc b nh tuyn trn Internet IPv6 s chuyn lu lng IPv6 ph hp vi prefix 48 bit n cc b nh tuyn thuc site ca t chc.

Subnet ID: Subnet ID c dng cho site ca t chc xc nh cc mng con. Kch thc ca trng ny l 16 bit. Site ca t chc c th dng 16 bit ny vi site ca n to 65.536 mng con hoc nhiu mc ca s phn cp nh a ch v mt c s h tng nh tuyn hiu qu.

Giao din ID: ch giao din trn mt subnet c th ca mt site. Kch thc ca trng ny l 16 bit. Cc trng vi a ch unicast ton cu to ra cu trc 3 cp nh hnh v:

Hnh 2.1: a ch Unicast ton cuTopology cng cng l tp hp ca cc ISP ln hn v nh hn m cung cp truy nhp vo Internet IPv6. Topo ca site l tp hp ca cc mng con trong cng site ca t chc. Ch th giao din ch mt giao din c th trn mt mng con trong cng site ca mt t chc. a ch Unicast dng ni b.

C 2 loi : a ch link-local v a ch site-local * a ch Link-Local.Cc a ch link-local c dng bi cc node khi truyn thng vi cc node lng ging trn cng 1 lin kt. V d nh trn mng IPv6 lin kt n khng c b nh tuyn, cc a ch link-local c dng truyn thng gia cc host trn link.Mt a ch link-local cn thit cho cc qu trnh x l tm kim lng ging v lun lun c t ng c cu hnh ngay c khi khng c tt c cc a ch unicast khc.

Hnh 2.2: M t cu trc ca a ch link-localCc a ch link-local lun lun bt u vi FE80. Vi 64 bit xc nh giao din. Prefix cho a ch link-local lun lun l FE80::/64. Mt b nh tuyn IPv6 chuyn lu lng link-local vt ngoi gii hn lin kt. * a ch Site khu vc (Site-Local).Cc a ch site-local tng ng vi khng gian a ch IPv4 ring ( 10.0.0.0, 172.16.0.0/24 v 192.168.0.0/16). V d cc mng ni b ring m khng c mt hng, nh tuyn kt ni n Internet IPv6 c th dng cc a ch site-local m khng xung t vi cc a ch Unicast ton cu. Cc a ch site-local khng n c t cc site khc v cc b nh tuyn phi khng c chuyn lu lng site-local ra ngoi site. Cc a ch site-local c th c dng thm vo cc a ch unicast ton cu. Mt site l mt mng t chc hoc 1 phn ca mng t chc m c nh ngha v mt a l, nh 1 c quan hay 1 t hp c quan, mt trng hc. Khng ging nh cc a ch link-local, cc a ch site-local khng c t ng cu hnh v c cp pht bi cc qu trnh cu hnh a ch stateful hay stateless. Cu trc ca a ch site-locak nh sau:

Hnh 2.3: M t cu trc ca a ch Site-Local 10 bit u tin lun lun c nh cho cc a ch site-local ( FEC0::/10). Sau 10 bit c nh l trng ID Subnet cung cp 54 bit m ta c th to ra mt c s h tng nh tuyn c th tm tt v phn cp trong cng 1 site. Sau trng ID mng con l 64 bit trng ID giao din m ch th mt giao din c th trn mt subnet.

a ch IPv6 c bit. * a ch khng ch r. a ch 0:0:0:0:0:0:0:0 hay :: ch c dng ch s khng c mt ca mt a ch. N tng thch vi a ch khng r trong IPv4 l 0.0.0.0. a ch khng ch r thng c dng nh l mt a ch ngun cho cc gi c gng xc nhn s c mt duy nht ca mt a ch khng ch r. a ch khng ch r khng c cp cho 1 giao din hoc l dng nh 1 a ch ch n.

* a ch loopback.

a ch loopback 0:0:0:0:0:0:0:1 hoc ::1 c dng xc nh 1 giao din loopback cho php 1 node c th gi cc gi gi ngc v chnh n. N tng ng vi a ch loopback 127.0.0.1 trong IPv4. Cc gi c nh a ch cho a ch loopback phi khng c gi trn ng lin kt hoc c chuyn tip bi 1 b nh tuyn IPv6.2.3.4.2. a ch Multicast IPv6.

Trong IPv6 lu lng multicast hot ng ging nh IPv4. Cc node IPv6 c nh v ty c th lng nghe lu lng multicast trn 1 a ch multicast ty . Cc node IPv6 c nh v ty c th lng nghe nhiu a ch multicast ti cng 1 thi im. Cc node c th tham gia hoc ri khi nhm multicast bt c lc no.

a ch multicast IPv6 c 8 bit u tin l 1111 1111. Mt a ch IPv6 multicast c th d dng nhn ra v n lun bt u bng FF. Cc a ch multicast khng th c dng nh l cc a ch ngun hoc l cc ch trung gian trong 1 tiu nh tuyn. Pha sau 8 bit u tin a ch multicast bao gm cu trc thm vo xc nh cc c, phm vi v nhm multicast.

Hnh 2.4: M t cu trc ca a ch MulticastCc trng trong a ch multicast l:

C: ch cc c c thit lp trong a ch multicast. Kch thc ca trng ny l 4 bit. Nh RFC 3513 c ch c nh ngha l c T( transient: tm thi). C T dng bit bc thp ca trng c. Khi c set v 0 c T ch ra rng a ch multicast l mt a ch multicast c cp thng trc, c cp pht bi IANA

(Internet Assigned Number Authority). Khi c set ln 1, c T ch ra a ch multicast ny l a ch multicast tm thi.

Phm vi: ch phm vi ca lin mng IPv6 cho lu lng multicast c d nh. Kch thc ca trng ny l 4 bit. Thm vo thng tin cung cp bi cc giao thc nh tuyn multicast , cc b nh tuyn dng phm vi multicast xc nh ni m lu lng multicast s c chuyn i. Cc gi tr thng thng nht cho trng phm vi l 1 ( phm vi giao din cc b), 2 ( phm vi lin kt ni b) v 5 (phm vi site ni b). V d lu lng vi a ch multicast l FF02::2 c 1 phm vi lin kt ni b th 1 b nh tuyn IPv6 s khng chuyn lu lng ny ra lin kt ni b.

ID nhm: ch nhm multicast v l duy nht i vi mi phm vi. Kch thc ca trng ny l 112 bit. Cc ID nhm c gn thng trc khng ph thuc vo phm vi. Cc ID nhm tm thi ch lin quan n 1 phm vi c th. Cc a ch t FF01:: n FF0F:: l cc a ch lu tr v c bit n nhiu. xc nh tt c cc node cho cc phm vi lin kt ni b v giao din ni b, cc a ch sau c nh ngha:

FF01::1 ( giao din-local scope all-nodes multicast address)

FF02::1 ( link-local scope all-node multicast address xc nh tt c cc b nh tuyn cho phm vi giao din ni b v site ni b, cc a ch sau c nh ngha:

FF01::2 ( giao din-local scope all-b nh tuyns multicast address)

FF02::2 ( link-local scope all-b nh tuyns multicast address)

FF05::2 ( site-local scope all-b nh tuyns multicast address)

Vi 112 bit cho ID nhm th c th c 2112 ID nhm a ch. Tuy nhin theo cch m cc i ch multicast IPv6 nh x sang cc a ch MAC multicast ca Ethernet nn RFC 3513 khuyn co cp pht ID nhm t 32 bit bc thp ca a ch multicast IPv6 v xt cc bit ID nhm cn li l 0. Bng cch ch s dng 32 bit bc thp mi ID nhm nh x 1 a ch MAC multicast duy nht. Hnh sau m t iu ta va trnh by:

2.3.4.3 a ch Node Solicited.i ch node solicicated lm cho thun tin trong vic query cc node mng trong vic chuyn a ch. Trong IPv4, cc khung ARP Request c gi sang broadcast cp MAC, gi n tt c cc node trong tng on mng, bao gm cc a ch khng chy IPv4. IPv6 dng cc bn tin Neighbor Solicitation thc hin vic chuyn i a ch. Tuy nhin thay v dng a ch multicast tt c cc node phm vi lin kt ni b nh cc ch bn tin Neighbor Solicitation, s gi n tt c cc node IPv6 trn lin kt ni b, a ch multicast solicited node c dng. a ch multicast solicited node bao gm prefix FF02::1:FF00:0/104 v 24 bit sau cng ca i ch IPv6 c chuyn sang. Hnh sau m t iu ta va trnh by.

Hnh 2.5: M t cu trc ca a ch Node Solicited 2.3.4.4. a ch Anycast IPv6.Mt a ch anycast c cp cho nhiu giao din. Cc a ch c nh a ch anycast c chuyn sang giao din gn nht m a ch anycast c cp. d dng cho vic phn pht, c s h tng phi nhn bit c cc giao din c gn a ch anycast v khong cch ca chng trong gii hn ca metric nh tuyn. Hin ti th a ch anycast ch c dng nh cc a ch ch v ch c gn cho cc b nh tuyn. Cc a ch anycast cp khng gian a ch unicast v phm vi ca mt a ch unicast l phm vi ca kiu a ch unicast t a ch anycast c cp.

a ch anycast Subnet - Route c nh ngha trc v l cn thit. N c to ra t prefix mng con cho mt giao din cho trc. thit k a ch anycast Subnet-B nh tuyn, cc bit trong prefix subnet c c nh ti cc gi tr thch hp v cc bit cn li c xt v 0. Tt c cc giao din ca b nh tuyn kt ni n n 1 mng con c cp a ch anycast Subnet - Route cho mng con . a ch anycast Subnet- Route c dng cho vic truyn thng vi mt trong nhiu b nh tuyn c ni n mng con xa.

2.3.5. S tng thch a ch.Nhm chuyn i t IPv4 sang IPv6 v s tn ti ca c 2 loi host, cc a ch sau c nh ngha: a ch tng thch IPv4.a ch IPv6, a ch 0:0:0:0:0:0:w.x.y.z hoc ::w.x.y.z c dng bi cc node IPv6/IPv4 m truyn thng dng IPv6. Cc node IPv6/IPv4 l cc node dng c 2 giao thc IPv4 v IPv6. Khi a ch tng thch IPv4 c dng nh 1 ch n IPv6 th lu lng IPv6 s t ng ng gi vi 1 tiu ca IPv4 v gi n ch dng c s h tng IPv4.

a ch c nh x sang IPv4

a ch c nh x sang IPv4 0:0:0:0:0:FFFF:w.x.y.z hoc ::FFFF:w.x.y.z c dng din t 1 node ch dng IPv4 sang 1 node IPv6. N ch c dng cho din t ni b. a ch c nh x sang IPv4 khng c dng nh l mt a ch ngun hoc ch ca 1 gi IPv6.

a ch 6 sang 4.a ch 6 sang 4 c dng cho truyn thng gia 2 node chy c IPv4 v IPv6 trn 1 c s h tng nh tuyn IPv6. a ch 6 sang 4 c hnh thnh bng cch kt hp prefix 2002::/16 vi 32 bit ca 1 a ch IPv4 public ca node v hnh thnh nn 1 prefix 48 bit. a ch IPv6 cho 1 Host.

Mt host IPv4 vi mt b thch ng mng n thng c mt a ch IP n c cp cho b thch ng . Tuy nhin, 1 host IPv6 thng c nhiu a ch IPv6, ngay c vi giao din n. Mt host IPv6 c cp cho cc a ch unicast sau y:- Mt a ch lin kt ni b cho mi giao din.

- a ch unicast cho mi giao din ( c th l 1 a ch site ni b v 1 hoc nhiu a ch unicast ton cu )

- a ch loopback ( ::1) cho giao din loopback.

Cc host IPv6 thng thng l logically multihomed bi v chng c t nht 2 a ch m chng c th nhn cc gi, 1 a ch lin kt ni b cho lu lng lin kt ni b v 1 a ch ton cu hoc site ni b c th nh tuyn c.Thm vo , mi host lng nghe lu lng trn cc a ch multicast sau:

- a ch multicast tt c cc node phm vi giao din ni b ( FF01::1)

- a ch multicast tt c cc node phm vi lin kt ni b ( FF02::1)

- a ch soliticated cho mi a ch unicast trn mi giao din.

- Cc a ch multicast ca cc nhm c tham gia trn mi giao din. a ch IPv6 cho 1 B nh tuyn.Mt b nh tuyn IPv6 c cp cc a ch unicast sau y:- Mt a ch lin kt ni b cho mi giao din. - Cc a ch unicast cho mi giao din ( c th l 1 a ch site ni b v 1 hoc nhiu a ch unicast ton cu)

- 1 a ch anycast subnet b nh tuyn.

- Cc a ch anycast thm vo ( option).

- a ch loopback ( ::1) cho giao din loopback.

2.3.6. a ch IPv4 v s tng ng IPv6IPv4 AddressIPv6 Address

Cc lp a ch Internet Khng tng xng trong IPv6

a ch multicast IPv4 (224.0.0.0/4)a ch multicast IPv6 (FF00::/8)

Cc a ch broadcastKhng tng xng trong IPv6

a ch khng r rng 0.0.0.0a ch khng r rng ::

a ch loopback 127.0.0.1a ch loopback ::1

Public IP addressGlobal unicast address

a ch IP ring ( 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16)a ch site cc b ( FEC0::/10)

a ch t ng c cu hnh (169.254.0.0/16)a ch lin kt cc b ( FF80::/64)

Cch th hin: k hiu du chm thp phn phn cchCch th hin: dng du hai chm c gin lc cc s 0 v nn cc s 0 lin tip

Th hin cc bit mng: dng Mt n mng con hoc chiu di prefixTh hin cc bit mng: ch dng chiu di prefix

Chuyn i tn DSN: bng ghi ti nguyn a ch host IPv4Chuyn i tn DSN: bng ghi ti nguyn a ch host IPv6

Chuyn i ngc DNSChuyn i ngc DNS

Bng 2.2: a ch IPv4 v s tng ng IPv62.4. Khun dng ca gi tin IPv6.

2.4.1. Khun dng gi tin IPv6.

Hnh 2.6 : Khun dng ca gi tin IPv6 Phin bn : 6. Lp vn chuyn : tng t cc kiu dch v ( Type of service) trong IPv4.

Nhn lung: dng nh du tt c cc gi tin cng thuc mt lung d liu.

VD: cng ting ni, cng video.

Trm ngun mun cc B nh tuyn trung gian x l cc thng tin cng lung ging nhau.

- Cc gi tin cng lung phi c a ch ngun , a ch ch v s nhn lung ging nhau.

- S nhn lung c pht sinh ngu nhin nhng khng c dng li khi thi gian sng ca lung vn cn tn ti trn mng.

- Nhn lung phc v cho truyn thng a phng tin.

di ti: Cha thng tin hu ch trong gi tin. Tiu tip theo:

- Tiu thm vo ph thuc ty chn b sung. N c t gia tiu ca IPv6 vi tiu ca tng trn.

- Tiu ny ch c a vo khi cn thit, trnh vic truyn nhng thng tin d tha.

- Mt s la chn :

+ Routing: yu cu gi tin phi i qua ng no.

+ Flagment: Trong trng hp cn phn mnh.

+ Yu cu c x l trn ng truyn: hop by hop.

+ Yu cu x l gi tin khi n ch.

+ Thng tin xc thc trm thu nhn bit thng tin ch thc ca my ngun khng b gi danh, khng b thay i. + M ha ni dung ca gi tin.

Gii hn bc nhy : s B nh tuyn m gi tin c php i qua.

a ch ngun. a ch ch.

- a ch ngun v a ch ch c 128bit.2.4.2. So snh khun dng IPv4 v IPv6.

Hnh 2.7: Khun dng gi tin IPv4/ IPv6

IPv4 IPv6

VersionCng trng nhng vi cc s phin bn khc nhau.

Tiu Lengthc loi b trong IPv6. IPv6 khng cha trng Tiu Length bi v tiu ca IPv6 lun lun c nh l 40 byte. Mi tiu m rng c kch thc c nh hoc c a ch ca ring n.

Type of Servicec thay th bng trng Traffic Class

Total Lengthc thay th bng trng Payload Length ch kch thc ca trng ti.

Identification, Fragmentation, Fragment Offsetc loi b trong IPv6. Thng tin phn mnh khng c trong tiu ca IPv6. N c cha trong tiu m rng phn mnh.

Time to livec thay th bng trng Hop Limit.

Protocolc thay th bng trng Next Header.

Tiu Checksumc loi b trong IPv6. Trong IPv6 vic pht hin li cp bit cho c gi IPv6 c thc hin bi lp lin kt.

Source AddressTrng ny ging nhau ch khc l a ch IPv6 c 128 bit.

Destination AddressTrng ny ging nhau ch khc l a ch IPv6 c 128 bit.

Optionsc loi b trong IPv6. IPv4 options c thay th bi IPv6 extension header.

Bng 2.3: So Snh khun dng gi tin IPv4/ IPv6

2.4.3. Cc tiu m rng ca IPv6.

Tiu ca IPv4 bao gm tt c cc option. V th, mi b nh tuyn trung gian phi kim tra s tn ca chng v x l chng khi chng hin din. iu ny lm gim hiu sut vn chuyn trong vic vn chuyn cc gi IPv4. Vi IPv6, cc option phn pht v c chuyn sang cc tiu m rng. Tiu m rng duy nht phi c x l ti mi b nh tuyn trung gian l tiu m rng Hop-by-Hop Option. iu ny s tng tc x l tiu v tng kh nng x l chuyn tip.RFC 2460 nh ngha cc tiu m rng IPv6 sau y phi c h tr bi tt c cc node IPv6:

- Hop-by-Hop Option tiu .

- Destination Options tiu .

- Routing tiu .

- Fragment tiu .

- Authentication tiu .

- Encapsulation Security Trng ti tiu .

Trong 1 gi IPv6 thng thng th khng c mt tiu m rng no. Nu vic iu khin c bit c yu cu bi cc b nh tuyn trung gian hoc ch th 1 hoc nhiu tiu m rng c thm vo bi host gi. Mi tiu m rng c phm vi 64 bit. Cc tiu m rng c kch thc thay i cha 1 trng tiu Extension Length v phi dng m khi cn chc chn rng kch thc ca chng l 1 bi s ca 8.2.5. Kt Lun. Trong chng 2, bi tiu lun gii thiu cc dng a ch, cu trc nh a ch IPv6, qua thy c s khc bit v thay i trong a ch IPv6. y l phin bn c thit k nhm khc phc nhng hn ch ca IPv4 v b sung nhng tnh nng mi cn thit trong hot ng v dch v mng th h sau. Chng tip theo s cp n vic trin khai mng IPv6 trn nn mng s dng IPv4.

Chng 3: TRIN KHAI MNG IPv6 3.1. Trin khai mng IPv6 trn nn IPv4.

3.1.1. Cc vn chung.IPv6 l mt giao thc Internet mi c thit k nhm p ng cc yu cu v pht trin cc dch v mi v m rng khng gian a ch trn mng Internet, ng thi khc phc nhng hn ch khc ca IPv4 hin nay khng h tr tnh m ca giao thc, dch v QoS, cc chc nng bo mt. Tuy nhin hai giao thc IPv4 v IPv6 khng thc s tng thch vi nhau Mt khc, h thng IPv4 pht trin mnh m v hin nay hnh thnh mt mng Internet ton cu c quy m ht sc rng ln c v kin trc mng v dch v trn mng. Do vy, trong mt tng lai gn khng th chuyn i mng t IPv4 sang IPv6 c. trin khai mng IPv6 hiu qu v thit thc, cc nh thit k a ra gii php l trin khai mng IPv6 trn nn mng IPv4.3.1.2. Mc ch.Thch thc m IPv6 phi i mt l kh nng chuyn i trn vn cc gi tin IPv6 t nh dng theo giao thc IPv6 sang IPv4 t c th vn chuyn trn nn h tng l mng IPv4; v hu ht cc thit b kt ni mng Internet hin nay u c thit k cho IPv4.

thc hin yu cu ny, qu trnh trin khai IPv6 phi m bo tnh linh ng mt cch ti a, nhng iu ny li mu thun vi quy m rng ln ca mng Internet. Do vy, y cng c th coi l mt im chnh trong qu trnh thit k IPv6, m bo s thnh cng ca mng IPv6. Khng m bo c yu cu trn s khng c s thnh cng ca mng IPv6.

VD: Trc y c mt vi giao thc c thit k th thay th TCP/IP, nh XTP nhng khng th thnh cng l do khng c kh nng chy song song (dual stack), hay khng c tnh tng thch ln nhau gia cc h giao thc c vo mi. Nhng tnh nng mi ca cc giao thc ny, nu mt mnh n s khng thuyt phc ngi s dng chuyn sang s dng.

IPv6 cng vy, nu vi cc c tnh u vit ca n so vi IPv4 cng cha thuyt phc ngi dng b mng IPv4 hin nay xy dng mng IPv6, do vy cn phi m bo tnh tng thch trn c s cc chc nng ca IPv4 trong qu trnh chuyn i sang IPv6.

trin khai mng IPv6 c cc phng thc din ra ng thi l xy dng mng IPv6 trn nn h tng l mng IPv4 hin nay, sau thay th dn mng IPv4 hin nay.

Mc ch ca cc c ch chuyn i l m bo mt s chc nng chnh nh sau:

m bo thc hin cc c tnh u vit ca mng IPv6 so vi mng IPv4

Tn dng h tng sn c ca mng IPv4 trong giai on chuyn tip sang mt mng thun IPv6

Tng cng kh nng nng cp v trin khai. Vic chuyn i i vi cc host/b nh tuyn khng b ph thuc vo nhau.

Ti thiu ho s ph thuc trong cc qu trnh nng cp. Mt trong nhng iu kin bt buc nng cp host vi IPv6 l h thng DNS server phi c nng cp u tin bi DNS l dch v h tr vic tm kim a ch phc v cho cc ng dng khc. Cch thc ci t v cu hnh DNS server IPv6 s c trnh by trong phn th nghim. Cc iu kin i vi cc b nh tuyn nh h tr cc giao thc nh tuyn BGP4+, h tr IPv6 cha phi l bt buc.

Gn v cp pht cc loi a ch thun tin. Khi cc h thng IPv4 c ci t c gn cc a ch IPv4; mt khc a ch IPv4 l mt tp con ca ca a ch IPv6, do vy c th tip tc s dng vi cc a ch IPv4 sn c. Ch gn cc a ch IPv6 tht s cn thit cho cc kt ni ti 6Bone v tun theo cc k hoch phn b a ch ca t chc .

Gi thnh khi im thp. V khng cn chun b cn thit nng cp cc h thng t IPv4 sang IPv6 khi trin khai mt h thng IPv6 mi. C ch ny c thc hin hon ton trn nn IPv4 c.

C ch chuyn i ca IPv6 l c th kt hp cc trm IPv6 cng lm vic vi cc trm IPv4 bt k ni no trn Internet cho n khi a ch IPv4 khng cn tn ti, v cho php cc trm IPv6 v IPv4 trong mt khng gian gii hn cng lm vic sau . Cc c ch ny m bo khon u t to ln ca ngi dng trong vic xy dng h thng mng IPv4 ng thi trin khai c mng IPv6.

3.2. Cc c ch chuyn i.Hin nay s lng cc mng IPv4 l rt ln; hu ht cc dch v v cc giao dch trn mng u da trn h tng mng IPv4; do vy xut hin nhiu c ch chuyn i cho php kt ni cc host IPv6 qua mng IPv4.

Vic xy dng li giao thc ca tng Internet trong m hnh TCP/IP dn n nhiu thay i. Trong vn thay i ln nht ca IPv6 vi IPv4 l vic thay i cu trc a ch. S thay i ny nh hng n cc vn sau:

nh hng ti hot ng ca cc giao thc tng trn ( Tng giao vn v tng ng dng)

nh hng ti cc phng thc nh tuyn.Mt khc , mt yu cu quan trng trong vic trin khai IPv6 l phi thc hin c mc tiu ban u ra khi thit k giao thc IPv6 l : IPv6 phi lm vic c trong mi trng s dng giao thc IPv4. S c hin tng ch c nhng host dng duy nht IPv6 v ng thi cng tn ti nhng host ch duy nht IPv4. ng thi nhng host thun IPv6 phi giao tip c vi nhng host IPv4 trong khi vn m bo a ch IPv4 l c tnh thng nht ton cu. Do vy, m bo thc hin cc s tng thch gia IPv4 v IPv6, cc nh thit k IPv6 xy dng mt s c ch chuyn i khc nhau.

Cc c ch chuyn i ny c nhng c im chung nh sau:

m bo cc host/b nh tuyn ci t IPv6 c th lm vic c vi nhau trn nn IPv4.

H tr cc kh nng trin khai cc host v b nh tuyn hot ng trn nn IPv6 vi mc tiu thay th dn cc host ang hot ng IPv4.

C mt phng thc chuyn i d dng, thc hin c cc cp khc nhau t pha ngi dng cui ti ngi qun tr h thng, cc nh qun l mng v cung cp dch v.

Cc c ch ny l mt tp cc giao thc thc hin i vi cc host v cc b nh tuyn, km theo l cc phng thc nh gn a ch v trin khai, thit k lm qu trnh chuyn i Internet sang IPv6 lm vic vi t ri ro nht c th c.

Hin nay cc nh thit k IPv6 a ra 3 c ch chuyn i chnh cho php kt ni IPv6 trn nn IPv4 nh sau:

Dual Ip layer: c ch ny m bo mt host/b nh tuyn c ci t c IPv4 v IPv6 tng Internet Layer trong kin trc TCP/IP ca n.

IPv6 tunnel qua IPv4: C ch ny thc hin ng gi mt gi tin IPv6 theo chun giao thc IPv4 c th mang gi tin trn nn kin trc IPv4. C 2 loi tunneling l ci t sn ( Configured) v t ng (Automantic). 6to4: C ch ny hot ng da trn cc host IPv4 sn c cc a ch IPv4 t xy dng mt a ch IPv6 c cu trc c bit; cc host s dng c ch ny khng cn phi thng qua mt ISP c h tr IPv63.2.1. Lp IP song song ( Dual IP layer). C ch ny m bo mt host/b nh tuyn c ci t c 2 giao thc IPv4 v IPv6. Vi c ch song song ny, hot ng ca cc host/b nh tuyn hon ton tng thch vi IPv4 v IPv6. Theo c ch ny, IPv6 s cng tn ti vi IPv4 v n s dng c s h tng ca IPv4. S la chn s dng ngn xp ( la chn giao thc no trong lp TCP/IP) s da vo thng tin c cung cp bi dch v qua DNS server.

Hnh 3.1: Minh ha c ch Dual IP layer

3.2.2. ng hm IPv6 qua IPv4.C s h tng mng Internet hot ng trn nn IPv4 hot ng kh n nh v c quy m rng ln. Tn dng kh nng ny, cc nh thit k IPv6 a ra gii php l thc hin c ch tunneling ( ng hm) trn nn IPv4.

Hnh 3.2: Minh ha c ch ng hm

C hai loi c ch Tunneling nh sau: l Automatic v Configured Tunneling.C hai c ch ny khc nhau c bn l vic quyt nh a ch cui ca qu trnh ng hm, cn li v c bn hot ng ca hai c ch ny l ging nhau.+ im khi to ng hm ( im ng gi tin) to mt tiu IPv4 ng gi v truyn gi tin c ng gi.

+ Node kt thc ca qu trnh ng hm ( im m gi) nhn c gi tin ng gi, xa b phn tiu IPv4, sa i mt s trng ca tiu IPv6, v x l phn d liu ny nh mt gi tin IPv6.

+ Node ng gi cn duy tr cc thng tin v trng thi ca mi qu trnh trong ng hm. V d cc tham s MTU x l cc gi tin IPv6 bt u thc hin ng hm. V s lng cc tin trnh trong ng hm c th tng ln mt s lng kh ln, trong khi cc thng tin ny thng lp li v do c th s dng k thut m v c loi b khi cn thit.

Hnh 3.3: C ch ng gi thc hin ng hm

Hnh 3.4: C ch m gi khi thc hin ng hm

3.2.2.1. Automatic Tunneling:Vi phng thc ny tunneling ny, a ch ch trong gi tin ng gi IPv4 c xc nh l a ch ch ca gi tin IPv6. Do vy, a ch ch ca gi tin IPv6 c ng gi phi c dng a ch IPv4 tng thch vi IPv6 ( IPv4 compability IPv6). i vi nhng gi tin IPv6 m a ch ch l dng a ch khng c dng IPv4-compabile th s khng th thc hin automatic tunneling.C ch Automatic Tunneling thng c s dng khi cn thc hin nhng kt ni vi cc host hoc vi cc mng IPv6 trong mt thi gian ngn, hoc trong nhng tnh hung ngu nhin.

Cc thng s lin quan n Automatic Tunneling Kh nng ng dng: i vi cc host.

Yu cu giao thc IPv4: Yu cu c cc kt ni IPv4 gia cc site.

Yu cu a ch IPv4: ti thiu c mt a ch IPv4

Yu cu giao thc IPv6: khng cn thit.

Yu cu a ch IPv6: i ch dng IPv4 compabile.

Yu cu i vi host: ci t dual satck IPv4/IPv6.

Yu cu i vi route: none. 3.2.2.2. Configured Tunneling

Vi phng thc ny tunneling ny, a ch m gi c quyt nh bi cc thng tin c cu hnh node ng gi. i vi mi tunnel dng ny, cc node ny phi lu a ch ca cc trm cui ( cc trm m gi end-point ). Khi cc gi IPv6 c chuyn qua tunnel ny, a ch ca cc endpoint c cu hnh sao cho ging vi a ch ch trong phn tiu ca gi tin IPv4 ng gi.

Cc thng s yu cu i vi c ch Configured Tunneling nh sau:

Kh nng ng dng :site.

Yu cu giao thc IPv4: kt ni gia cc site s dng IPv4.

a ch IPv4: ti thiu c mt a ch IPv4 trong mt site.

Yu cu giao thc IPv6: khng cn thit.

Yu cu v a ch IPv6: khng cn thit .

Yu cu host: IPv6 stack hoc IPv4/IPv6 stack.

Yu cu i vi b nh tuyn: IPv4/IPv6 b nh tuyn.3.2.3. 6to4.

Hnh 3.5: C ch 6 to4

Hin nay, trin khai mng IPv6 t chc IGTRANs ( Ipng Transition Working Group - mt nhm thuc IETF) a ra mt gii php th ba trin khai mng IPv6 trn nn IPv4 l c ch 6to4. Mt trong nhng hn ch ln nht ca hai c ch trn ( c ch dual stack v c ch tunneling) l vi mi khch hng cui ( end- user site) kt ni vi mng IPv6 u cn phi la chn mt ISP c h tr dch v IPv6 gii quyt cc vn lin quan n cp pht a ch v tunneling.. Mt khc phng php ny cng hn ch c nhng kh khn ca c ch tunneling nh cc hot ng to, qun l, duy tr cc cu hnh tunneling ca phng php tunneling.Yu cu:

Mt host phi c a ch IPv4.

m bo hot ng chnh xc ca 6to4 trong mt topo mng phc tp, tt c cc host IPv6 phi m bo thut ton sau y l c gi tr: l thut ton lin quan n la chn a ch khi thc hin gi gi tin IPv6. V ta bit rng mt node c th gn nhiu dng a ch IPv6 khc nhau. Do vy, trong dch v tn min DNS c th khai trin nhiu bn ghi tng ng vi cc a ch IPv6 khc nhau ca host . Thut ton la chn a ch m bo trong mt tp cc a ch IPv6 tr v khi host thc hin query DNS server s la chn mt a ch c dng tin t 2002::/16 trong tp cc a ch tr v gi cc gi tin IPv6 trong cc kt ni ca host .

3.3. Kt Lun

Trong chng ny, bi tiu lun cp n cng ngh chuyn i IPv6-IPv4. Trong thi gian u pht trin, kt ni IPv6 cn thc hin trn c s h tng mng li IPv4. Mng Ipv6 v IPv4 s cng song song tn ti trong thi gian di, thm ch l mi mi.KT LUN Thng qua bi tiu lun ny, em xem xt nhng vn c bn ca cu trc a ch IPv4, a ch IPv6, cch thc chia a ch mng v a ch host, qua gip ta hiu c r hn v cch thc lin kt trn Internet. Vic pht trin thm mt phin bn a ch mi s p ng c nhu cu pht trin cng ngh thng tin hin nay. Qu trnh trin khai phin bn a ch mi trn nn phin bn a ch c sn l khng h n gin,bi tiu lun ny cp n mt vi c ch chuyn i phin bn a ch mi sao cho ph hp vi phin bn a ch c, nhng ng dng hiu qu vo thc t th vn cn phi nghin cu chi tit hn.Trong qu trnh lm tiu lun, do ti liu tham kho cn nhiu hn ch nn bi tiu lun khng th trnh khi nhng thiu st, em mong nhn c s gp ca thy c v cc bn ngy cng hon thin thm kin thc ca mnh.

Em xin chn thnh cm n!

TI LIU THAM KHO1. Hong Trng Minh- Gio trnh nh Tuyn Trong Mng Vin Thng.2. Nguyn Vn Tam- Gio trnh L Thuyt Mng. 3. Cu trc a ch ca Internet

http://manguon.com/EBook.aspx?EBookGID=45444. Cc vn trin khai mng IPv6

http://manguon.com/EBook.aspx?EBookGID=45445. Gio trnh CCNA, CCIE - Cisco Networking Academy Program.

6. Introduction to IP Version 6 - Microsoft Corporation. Published: September 2003

Updated: March 2004PAGE 19