OSPF2- OSPF

www.williamspublishing.comwww.ciscopress.ru ciscopress.com

. II CCIE 9360

32.973.26-018.2.75

56 681.3.07 "" . .. .. "" : info@williamspublishing.com, http://www.williamspublishing.com

, . II 56 OSPF, 2- . : . . .: "", 2004. 816.: . . . . ISBN 5-8459-0594- (.) OSPF, , , , , , . OSPF , , Internet , OSPF. . , , TCP/IP. , OSPF, , : , , , , , .. 32.973.26-018.2.75 . , , , Cisco Press. Authorized translation from the English language edition published by Cisco Press, Copyright 2003 All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage retrieval system, without permission from the Publisher. Russian language edition published by Williams Publishing House according to the Agreement with R&I Enterprises International, Copyright 2004 Cisco, http://www.academy.ciscopress.ru. ISBN 5-8459-0594- (.) ISBN 1-5870-5032-3 (.) "", 2004 Cisco Press, 2003

I. OSPF 1. 2. OSPF 3. OSPF II. OSPF 4. 5. 6. 7. OSPF III. , , OSPF 8. OSPF 9. OSPF 10. BGP MPLS OSPF IV. OSPF . RFC, OSPF 27 29 77 141 201 203 301 389 459

495 497 593 713 767 769 788 791

, , 15 16 18 19 20 22 23 23 23

I. OSPF 1. OSI OSI OSI OSI , TCP/IP TCP/IP TCP IP , IP D IP- IP- IP- IP , VLSM CIDR

2729 30 31 31 34 35 36 38 39 39 40 41 42 42 42 43 48 49 50 50 50 51 51 55 55 56 57 59 60

VLSM VLSM CIDR , CIDR IP CIDR IP CIDR : VLSM

61 62 63 64 66 66 67 68 68 69 69 70 71 72 73

2. OSPF - SPF SPF OSPF OSPF OSPF OSPF OSPF OSPF : OSPF : : OSPF OSPF OSPF

7778 80 82 88 89 91 95 96 97 104 105 105 107 111 111 113 115 116 117 118 121 124 132 133 133 134 138

3. OSPF LSA LSA OSPF OSPF LSA LSA OSPF LSA LSA MOSPF - LSA LSA : OSPF : , , ,

141 141 141 151 158 158 159 164 164 166 166 169 169 170 170 171 172 172 173 178 188 189 191 196 197

II. OSPF 4. OSPF OSPF OSPF 1: 2: 3: 4:

201203 204 205 205 205 206 206 207 207 208 212 220 226

8

5: IOS Cisco 6: , OSPF OSPF ABR , OSPF , OSPF OSPF 0 0 OSPF - OSPF : :

227 229 230 231 231 233 234 235 236 237 237 241 241 242 242 243 243 243 244 246 247 247 248 248 250 251 251 254 255 258 258 259 260 261 273 273 275 275 276 276 276 276 277 277 279 282 284

9

: OSPF 5. OSPF OSPF OSPF OSPF OSPF OSPF OSPF OSPF , : OSPF : OSPF : OSPF 6. OSPF , 1: 2: RIP OSPF 3: 4: OSPF EIGRP

285 287 290 301 301 302 307 311 312 314 314 317 318 319 321 324 333 363 372 379 379 380 385 389 390 392 393 394 398 399 406 407 411 413 414 418 419 429 433

10

5: OSPF RIP 6: 7. OSPF OSPF OSPF

443 449 456 459 460 462 464 465 466 487 487

III. , OSPF 8. OSPF SNMP SNMP SNMP MIB OSPF OSPF OSPF : Secure IOS : , - 9. OSPF OSPF

495497 498 500 503 506 511 519 522 524 524 531 538 552 552 565 566 579 580 580 581 588 589 590 593 593 594 595

11

, OSPF OSPF (System Logging SYSLOG) , OSPF show ip ospf show ip ospf process-id show ip ospf interface show ip ospf border-routers show ip ospf database show ip ospf delete () show ip ospf events () show ip ospf flood-list show ip ospf maxage-list () show ip ospf neighbor show ip ospf neighbor ip address show ip ospf neighbor int ip-address show ip ospf neighbor detail show ip ospf virtual-links show ip ospf stat () show ip ospf summary-address clear ip ospf debug OSPF debug debug debug debug, OSPF : OSPF 1 2: : OSPF OSPF OSPF OSPF OSPF OSPF 10. BGP MPLS OSPF EGP BGP BGP BGP BGP OSPF

601 601 603 611 611 614 615 617 617 633 636 639 640 640 641 642 642 643 644 645 645 648 648 649 650 650 675 676 676 688 693 694 694 696 703 707 709 713 713 715 719 719 721 724 726

12

, OSPF : MPLS OSPF MPLS MPLS IP ATM , MPLS OSPF MPLS

730 732 739 740 740 743 744 746 747 748 750 758 764

IV. OSPF . RFC, OSPF RFC, OSPF RFC 1131 OSPF RFC 1245 OSPF RFC 1246 OSPF RFC 1247 OSPF 2 RFC 1248 OSPF 2 RFC 1252 OSPF 2 RFC 1253 OSPF 2 RFC 1364 BGP OSPF RFC 1370 OSPF RFC 1371 IP RFC 1403 OSPF RFC 1583 OSPF 2 RFC 1584 OSPF RFC 1585 MOSPF: RFC 1586 OSPF Frame Relay RFC 1587 OSPF, NSSA RFC 1745 BGP4/IDRP IP-: OSPF RFC 1765 OSPF RFC 1793 OSPF , RFC 1850 OSPF 2 RFC 2178 OSPF 2 RFC 2328 OSPF 2

767769 769 772 772 772 774 774 774 775 775 775 776 776 776 777 777 778 780 782 782 783 783 784 784

13

RFC 2370 OSPF, LSA RFC 2676 QoS OSPF RFC 2740 IPv6 OSPF RFC 2844 OSPF ATM Proxy-PAR

786 787 787 787 788 788 791

14

. II (Thomas M. Thomas II), (Network Emergency Repair Dude, NERD), CCIE1 9360. , Cisco Systems CCNP2, CCDA3 CCNA4. , , , , , . NetCerts.com ( CCPrep.com) International Network Resource Group (www.inrgi.net), , . Chesapeake Computer Consultants, Inc. (CCCI) Cisco Systems. , OSPF Network Design Solutions , . US Networks, Inc. (www.usnetworksinc.com) (Voice-over-IP VoIP) IP. . , , , , .

1 CCIE (Cisco Certified Internetwork Expert Cisco). 2 CCNP (Cisco Certified Network Professional Cisco). 3 CCDA (Cisco Certified Design Associate Cisco). 4 CCNA (Cisco Certified Network Associate Cisco).

(Henry Benjamin), CCIE 4695, CCIE ( , Internet ). Cisco Systems, , . CCIE CCNP Practical Studies: Routing ( Cisco Press) CCIE Routing and Switching Exam Cram ( Coriolis). . (Matthew H. Birkner), CCIE 3719, Cisco Systems IP MPLS. . , , Cisco , MPLS . " CCIE" Cisco Internetwork Design ( Cisco Press). , . (Rick Burts), CCIE D 4615, 20- . Cisco Systems CCIE ( ). Cisco OSPF Mentor Technologies. OSPF, . Chesapeake NetCraftsmen (www.netcraftsmen.net). , , . . (Daniel L. Golding) Internet America Online ( AOL). Internet AOL Time Warner . . Internet, . , , (North American Network Operator's Group NANOG). (John Hammond) Jumper Networks. Chesapeake Computer Consultants, Inc., Cisco .

( 1990 ) . ( Riddock), CCNP CSS11, , . CISSP2 CCSP3. Cisco (Managing Cisco Network Security MCNS), Cisco Press, .

CSS1 (Cisco Security Specialist 1 Cisco 1 ). CISSP (Certified Information Systems Security Professional ). 3 CCSP (Cisco Certified Security Professional Cisco).2

1

17

, , , . , . . , . , , 15 .

, , . , , - . , , . , , . , . , . . , . (Amy Moss), , (Chris Cleveland), , , , .

, , , , . 1.

. 1. ,

, . 2. , . 3.

,

21

, , Cisco IOS Software Command Reference. , Command Reference, . (|) , . ([ ] ) . ({}) . ( [ { } ] ) . , , . ( ) , ( show). , .

22

, ...

OSPF . , , OSPF, , , . , OSPF , , , . , OSPF, , , , , , OSPF. , , OSPF , , Internet , OSPF.

, . , OSPF. , OSPF, . OSPF , , , , , , ..

, , . , , . 1, " ". , , , , , , .

2, " OSPF". , , , . , . 3, " OSPF". , OSPF , . , (Link-State Advertisement LSA), OSPF, OSPF, OSPF . 4, " ". , OSPF, , , OSPF . , , . OSPF. , , . 5, " ". , . , OSPF. 6, "", 7, " OSPF". , , , , , , () OSPF OSPF . 8, " OSPF". OSPF , . , . 9, " OSPF". OSPF, . , OSPF, , , -

24

. , , . 10, " BGP MPLS OSPF".

OSPF , , OSPF , (Multiprotocol Label Switching MPLS). EGP, OSPF BGP.

25

". 40 , , , . Intel . , 20 ; . 1995 , , . 2012 , , Intel 1 , 10 . , 100 000 (Million Instructions Per Second MIPS). Pentium II, 386. , , , ! . 1.1 , .

. 1.1. ,

, , . , , , , , . OSI.

30

I. OSPF...

OSI Open System Interconnection ( ). "" , OSI, , , . OSI . , , , - , , , , OSI.

OSI OSI , , . , , , , , , . , , , , . , (International Organization for Standardization ISO) OSI. OSI 1970- 1980- 1990- . , , ISO.

OSI . 1.2 , . , , Network Associates, , OSI . . 1.2 , . , OSI, Web- . Acterna ( W&G) OSI, ATM, ISDN - www.acterna.com/shared/ forms/poster_form.html. Network Associates Guide to Communications Protocols no www.sniffer.com/dm/ protocolposter.asp.

1.

31

. 1.1 1.2 , OSI 7 1 .

OSI OSI : . , . .1 2

-, . , .

34

I. OSPF.

OSI ( 5, 6 7) , . . . , , OSI. .

, - . , , , .

7 . (cc:Mail, MS Outlook ..) (Secure CRT Telnet FTP Voyager FTP) . , , , . , , (Network File System NFS) Windows.

6 ( ) . , Microsoft Exchange , Lotus Notes. , , , EBCDIC (8-) , ASCII (7-). , , PGP (Pretty Good Privacy).

5 OSI, . RPC (Remote Procedure Call ), Sun Novell, 5.

1. 35

OSI (14) , . , . , . .

4 , , . , (Transmission Control Protocol TCP), , ( ) OSI. , , OSPF (Open SPF SPF) FTP (File Transfer Protocol ), , TCP. TCP, , , UDP (User Datagram Protocol ), , , , TCP. , UDP, (Trivial File Transfer Protocol TFTP) (Simple Network Management Protocol SNMP). UDP , Real Audio.

3 . (Internet Protocol IP), IP-. , IP- , . , , IP- , . , , - 10.10.10., , , 10.20.20.x, . IP- -

36

I. OSPF...

, " ". , IP- : , .

2 , , . , , ( , 3 ). , , , (Media Access Control MAC), -. , Ethernet . , - ; . , 2, -, . , IEEE 802, OSI, (Data Link Control DLC), DLC-. , Frame Relay 2 (DataLink Connection Identifier DLCI). - 6 , 48 ; 24 (Organization Unique Identification OUI) 24 . Web- (Institute of Electrical and Electronic Engineers IEEE). IEEE Ethernet Ethernet. 3 Ethernet , 3 , . . 1.3 Ethernet, , Cisco Systems. 1.3. Ethernet ~0000

, Cisco01 23 45

"

- (OUI) (Organization ID OID). , IEEE , . 1.3.

1.

37

1 , OSI, (, , , ). , , , , . : , . . 1.3.

. 1.3. OSI

OSI OSI , . , OSI. . . , . . , .

38

I. OSPF...

OSI , .

, ( ), , , . , 3 , . ( 2) , , ( 3 ), . , OSI , , . . . 1.4 , . 2 3 4

. 1.4. OSI, OSI

, . ( Web) , OSI , , , . , , . TCP/IP, Internet.

TCP/IP , . TCP/IP. -

1. 39

TCP/IP. TCP/IP , . , OSPF. TCP/IP, TCP/IP, . TCP/IP Transmission Control Protocol/ Internet Protocol ( / ). TCP IP TCP/IP, TCP/IP . TCP/IP 25 ARPAnet , Internet , TCP/IP , TCP/IP , . TCP/IP . TCP/IP Internet , . TCP/IP OSI, , OSI, OSI. TCP/IP , IP. , TCP/IP 3 OSI. . 1.5 OSI TCP/IP.

. 1.5. OSI TCP/IP

TCP/IP OSI , TCP/IP . , , Internet.

40

I. OSPF...

TCP/IP , TCP IP . TCP. IP , . , , . 1.3. , IP , , . , Ethernet Token Ring, IP . Internet , -. , IP . IP, .

(IP ICMP ) (TCP UDP), TCP/IP , , FTP, Telnet .. TCP/IP, TCP/IP, . . TCP/IP TCP/IP Illustrated, Volume 1 (Richard Stevens). , . , . , , - , , .3

TCP TCP , . TCP TCP. TCP TCP/IP . , . . . ICMP (Internet Control Messages Protocol Internet).

3

1. 41

. .

IPIP . , TCP ( ). , U DP, , UDP . IP TCP/IP . , . , , . , , .

, , .

, , . OSI TCP/IP. , OSI, , , . TCP/IP . , . .

, , , , , , , . . Ethernet. , , , ; 10 /. Ethernet . Fast Ethernet Gigabit Ethernet, , - .

42

I. OSPF...

Fast Ethernet. Ethernet, , . Ethernet ; Fast Ethernet 100 /. Gigabit Ethernet. Ethernet, 1 /. Gigabit Ethernet, - , , . Token Ring. , 1969 . , , , 4 16 /. Token Ring, , , IBM, . FDDI (Fiber Distributed Data Interface - ). - , 100 /. FDDI , Gigabit Ethernet SONET (Synchronous Optical Network ). SONET .

Ethernet . 1.6.

. 1.6. Ethernet

Web-: www.ethermanage.com/ethernet/ethernet.html

, , . , , . .

1.

43

Frame Relay. , , . Frame Relay , . . , "-" (Point-to-Point Protocol ), IP, . ATM (Asynchronous Transfer Mode ). ATM , ITU-T (International Telecommunication Union Telecommunication Standardization Sector ). . ATM , , , , . , ANSI (American National Standards Institute ) ITU-T, . ATM , , IP. ISDN (Integrated Systems Digital Network ). , - . ISDN . DSL (Digital Subscriber Line ). Internet, . DSL , . , DSL, (ADSL4), , . DSL . DSL , . DSL ISDN 1.

4

ADSL (Asymmetric Digital Subscriber Line ).

44

I. OSPF...

. , . , , , World Wide Web. " " , , , , . , , (Cable Modem Termination System CMTS) ( ). SONET. - , Bellcore 1980- . ANSI. SONET, , SDH (Synchronous Digital Hierarchy ). SONET OSI. ANSI SONET , , (Optical Carrier ), 51,8 / ( ) 2,48 /. SONET, ITU, SDH. SONET ISDN (Broadband ISDN BISDN). SONET, , ATM. DWDM (Dense Wave Division Multiplexing ). , - , TDM (Time-Division Multiplexing ). DWDM TDM, . . DWDM 80 ( ) ( ) - . DWDM WDM (Wave Division Multiplexing ). ( ) , , . , DWDM - SONET, ATM.

1. 45

. . . 1.7 , .

DSL

: 1/1 1/1 /

/

ISDN 56 /

.25 Frame Relay ( ) ATM SMDS

. 1.7.

. 1.4 1.5 . . ; 1.4. DS ! ( . 1.4 1.5 ) ; DS (Digital Signal ) DSO

] ;

DSO DS1 DS1C DS2 DS3

64 / 1 ,544 / 2,048 / 3,1 52 / 6,312 / 8,448 / 34,368 / 44,736 /

1 24 32 48 96 128 512672 28 - -3 DS1

-1 -1 -2 -2 -3

46

I. OSPF...

. 1.4 DS (Digital Signal ) DSO -4

DS4/NA

139,264 / 139,264 / 274, 176 / 565, 148 /

20482176

-

-5

DS4 -

4032 4 -4

1.5. SONET SDH ( . 1.4 1.5 ) SONET -1 (STS-1) -3 (STS-3) OC-12(STS-12) 51 ,84 / 155,52 / 622,08 / SDH STM-0 STM-1 STM-4 SONET SDH

28 DS-1 21 1 1 DS-3 84 DS-1 63 1 3 DS-3 1 4 336 DS-1 12 DS-3 252 1 4 4

-48 (STS-48)

2,488 /

STM-16

1344 DS-1 1008 1 16 4 48 DS-3 5376 DS- 4032 1 1 1 92 64 4 DS-3 -

OC-192(STS-192)

/

STM-64

-256 -768

13,271 / 40 /

-

-

. 1.4 1.5: STS-1 -1, ; STS-1 = OC1 = 51,84 / ( ); STS-3 = = STM-1 = 155 /; STS-9 = 9 = STM-3 9- ( ); STS-12 = = STM-4 = 622 /;

1. 47

STS-18 = OC18 = STM-6 18- ( ); STS-24 = 24 = STM-8 24- ( ); STS-36 36 = STM-12 36- ( ); STS-48 = 48 = STM-16 = 2,5 /; 1 = 2,048 / 32 64 /; 4 1 = 2; 4 2 = ; = 34 / ( ); STM ( ITU-T) (Synchronous Transport Module);

= 64 /;

STS ( ANSI) (Synchronous Transfer Signal); ( ANSI) (Optical Carrier). STM-1, SDH, , STS-3 SONET, , , .

, IP , IP, , , (Variable-Length Subnet Mask VLSM) (Classless InterDomain Routing - CIDR). . , , TCP/IP, 32- IP-. IP- , , . , , , . , , IP . IP- , 0 255. . -

48

I. OSPF...

. , . . 1.8 IP-, .-8 -8 -8 -

8 -

172

24

248

100

. , , , 00000000-11111111.. 1.8. IP-,

IP- , . . , . ; Internet, ARIN (American Registry for Internet Numbers) , RIPE (Reseaux IP Europeens) APNIC (Asia Pacific Network Information Centre) . , , () . , 172.24. , 248.100. 172.24.248.100. , .

, OSPF, IP- : .../8, /16 /24. IP- . (/) .

( /8) , . 0. , ( 0) 128, 00000000 , 127 . , , 127.0.0.0 , 10.0.0.0 . , 126 ( ). 126 , 16 777 214 ,

1. 49

IP- , 1, . CIDR /19 /20. Cisco , , 1 0, , .

( /16) . 10; , , 1 0. , 1 2 8 . 0 . 0 . 0 191.255.255.255. 6 8 , 16 384 . 65 534 .

( /24) . 3 110. , 1 9 2 . 0 . 0 . 0 2 2 3 . 2 5 5 . 2 5 5 . 2 5 5 . 5 8 , 2 097 152 . , 254 .

D D , . 4 1110. , 224 239. D , . Cisco (Cisco Discovery Protocol CDP), ICMP, Internet (Internet Group Management Protocol IGMP), , , Cisco IOS 11.2. . , . , IP- 2 2 4 . 0 . 0 . 5 , ( OSPF), Ethernet.

50

I. OSPF...

2 4 0 . 0 . 0 . 0 2 5 5 . 2 5 5 . 2 5 5 . 2 5 5 . 1111. IP. , - , , 6 IP (IPv6). IP- , . , IP- , (.. ), , (.. ). RFC 1918 Address Allocation for Private Internets IP-. 10.0.0.010.255.255.255. . 172.16.0.0172.31.255.255. . 192.168.0.0192.168.255.255. .

10/8, 172.16/12 192.168/16, .

IP- ( ) . IP- ( ) . . 1.6 , IP-. , N , . , . . 1.71.9 , IP- , . , 0 1, .

1. 51

10

()

/ 7/24 14/16

N.H.H.H N.N.H.H N.N.N.H

1.0.0.0-126.255.255.255 128.0.0.0-191.255.255.255

16 777 214 (2 - 2)65 534 (216-2)

24

D

110 1110 11110

192.0.0.0-223.255.255.255 21/8 224.0.0.0-239.255.255.255 240.0.0.0-254.255.255.255 -

254 (2 - 2)

8

2 3 4 5 6 7 8 9 10 11 12 13 14

251200 5.9.. 252400 5.2.. 252000 5.4.. 252800 5.4.. 252200 5.5.. 252400 5.5.. 252500 5.5.. 255.255.128.0 255.255.192.0 2525240 5.5.2. 2525200 5.5.4. 2525280 5.5.4. 2525220 5.5.5.

2 6 14 30 62 126 254 510 1022 2046 4094 8190 16382

4194302 2097150 1 048 574 524 286 262 142 131 070 65534 32766 16382 8190 4094 2046 1022

. 1.7 15 16 17 18 19 20 21 22

255.255.254.0 255.255.255.0 255.255.255.128 255.255.255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252

32766 65534131 070 262 142 524 286

510 254 12662 30 14

1 048 574

2097150 4194302

6 2

; 1.8. / IP- " 255.255.192.0 255.255.224.0 255.255.240.0 255.255.248.0 255.255.252.0 255.255.254.0 255.255.255.0 255.255.255.128 255.255.255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252 2 614 30 62

>-;':, ''/

* '" -j

163828190

2 34 5 6 7 8 910 11 12 13 14

4094 20461022510 254 12662 30 14

126 254 510

10222046 4094

819016382

6 2

1.9. / IP- .,, 2 3 4 5 6

255.255.255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252

2 614 30 62

62 30 14

6 2

, , , N 1 256. , 2. , N. . . N * * * , (256 * 256 * 256) - 2 = 16 777 214. ( 16 777 214, 16 .) . 1.9 IP- . 024

i; 8 64 32 16 8 4 2 11416

1 0

1 1 0

. 1.9. IP- IP-, , , . , IP- , (.. ), , (.. ).

54

I. OSPF ...

IP- IP . . , IP- 172.24.50.10, (172) . , (24) .., , , . , . , . IP-, (. 1.10).IP- 32 (.. ) IP- 8 16 10 24 110 . 1.10. IP-

, , . , 919-779-, , , 919, , 779 , , . , , , 888. , , , , 800 , .

IP- ( ) . IP- ( ) .

1.

55

. IP- . - , , , . , Token Ring IP- 172.24.248.100. , , 172.24.0.0, .

IP . , ; . . . . . .

, . , 1. , . , , , . , , . 1. . 2. . 3. IP- . . , (172.24.0.0) 256 172.24.0.0, 172.24.1.0, 172.24.2.0 .. 254 .

RFC 1812, 5.3.5.3, , , 1.

56

I. OSPF ...

, IP-. 1 , . , 32- , IP- , . , , IP- . , 172.24.1. 255.255.255.0. , IP- 172.24.1.0 255.255.255.0. Ethernet , 172.24.1.30, , ( IP- ), , 172.24.1.0, Ethernet . , , , . , IP-. . 255.0.0.0. . 255.255.255.0.

. 2 5 5 . 2 5 5 . 0 . 0 . l , IP-. , , , . , , , IP- . : " ?" , , : " ?" , . Ethernet, , , . , , , . , , , , -. , , . , , . -

1.

57

, Ethernet ; , . , , , , . , , , . . , , , . , , , . , , , , . , , 1 1 7 2 . 2 4 . 0 . 0 , 2 10.37.0.0. IP- (, .. 1.1) , , . . 1.11. 172.24.1.1 IP- 172.24.50.10 #1 JBP #2 10.37.1.1 IP- 10.37.100.212

. 1.11.

. , 1 IP- 172.24.1.1 2 5 5 . 2 5 5 . 0 . 0 , , 1 7 2 . 2 4 . 0 . 0 , . , , , ( 172.24.0.0 10.37.0.0), , , (). , IP- 10.37.100.212. , IP- , IP, (10.37.1.1)? . , IP- 10.37.1.1 2, .

58

I. OSPF ...

. , Cisco IP-, .

2 255.255.0.0, , , IP- (10.37). 2. , 255 , , 0 , , , . 2 5 5 . 2 5 5 . 2 5 5 . 0 , , , , IP- . , , , . , . , RFC, . , .

, , , , VLSM, , VLSM ( OSPF 1), . , VLSM ( RIP-12), . , , , , , . . . , , , . , , , . .1 2

BGP (Border Gateway Protocol ). RIP-1 (Routing Information Protocol version 1 1).

1. 59

RFC 791, Internet Protocol. RFC 950, Internet Standard Subnetting Procedure. RFC 1219, On the Assignment of Subnet Numbers. RFC 1700, Assigned Numbers. RFC 1918, Address Allocation for Private Internets.

Co RFC Web-www.isi.edu/in-notes/rfcxxxx.txt,

RFC.

VLSM CIDR VLSM . . CIDR , BGP-4 . , . CIDR IP, , , , . VLSM CIDR IP-. , IP-, IPv4, IP-. , . CIDR VLSM , . CIDR , , Internet . CIDR, Internet .

, , . , , - . Internet , .

60

I. OSPF ...

, Internet . , , , . , , , . IP 6 ( IPv6), IP (IP next generation IPng), . IP ( IPv4), . IPv6 Internet (Internet Engineering Task Force IETF) 1992 . . IPv6 IP-, , , .

IPv6 12.2 Cisco IOS. Web-: www.cisco.com/warp/public/cc/pd/iosw/ prodlit/pfgrn_qp.htm. IP IP- , VLSM CIDR. IP-, , , . Internet. , Internet, , , , , VLSM CIDR. , , VLSM CIDR.

, , , , . , , , :172.24.100.0/24 172.24.101.0/24 172.24.102.0/24 172.24.103.0/24

1. 61

: " , 172.24.100.0/22". , IP-. , , , . . 1.12 , . > , (

, ,

. 1.12.

3 Internetwork Design Guide Cisco. Web- www.cisco.com/univercd/cc/td/doc/ cisintwk/idg4/. CIDR, . . IP-, . 32- IP- . ( /16, 255.255.0.0) 32- IP-, .

, . , , . .

. , -

62

I. OSPF ...

, RIP IGRP (Interior Gateway Routing Protocol ). , . .

. -, . -, . . 1.13 , . : IP, OSPF. ( , ) . , ,

182.68.10.16 255.255.255.240 . 1.13.

, . . , . IP- . OSPF. . , . .

1.

63

, Cisco (Cisco Express Forwarding CEF). .

VLSM VLSM . , , , .

VLSM . VLSM, , VLSM. , , OSPF, BGP, EIGRP (Enhanced IGRP ), IS-IS (Intermediate System-toIntermediate System ) RIP 2 (RIP-2). VLSM , OSPF . VLSM , IP-. VLSM , , . , , . 1.1 , 30- , 2 , . .r

r*-r-,

-HVU"~ --

; 1.1. 'interface ethernet ip address 131.107.1.1 255.255.255.0 ! 8 Ethernet interface serial 0 ip address 131.107.254.1 255.255.255.252 ! 2 ! OSPF, ! 107 router ospf 107 ! , network 131.107.0.0 0.0.255.255 area O.O.O.O

64

I. OSPF ...

1.1, VLSM , , , . . VLSM, . . 1.14 , 172.24.10.0 6 . 6 63 . , VLSM 172.24.10.0.

172.24.10.4/30 255.255.255.252

172.24.10.8/30 255.255.255.252

172.24.10.12/30 255.255.255.252

172.24.10.16/30 255.255.255.252

172.24.10.25/24 255.255.255.0

. 1.14. VLSM

IP- , IP- . IP- , , , IP- . , . , , 20% 20% , , IPv4, , IPv6. , .

1.

65

VLSM VLSM . . . VLSM , . VLSM , . .

, VLSM . , , , OSPF, EIGRP, IS-IS RIP-2. , , VLSM, . , VLSM . , VLSM, . , .

CIDR VLSM , , . CIDR, RFC 1517, 1518, 1519 1520. CIDR , IP- . 19941995 . CIDR, RFC 1817, Internet , , . CIDR , , RIP-2, OSPFv2 BGP-4. CIDR . , , , , . IP-, , -

66

I. OSPF ...

( , ).

, Internet , Internet. Co Internet, , . 1988-1991 . Internet 10 . , 1995 . 80 000 . 25 , , . CIDR 1996 . 42 000. Internet 100 000 . CIDR, , , 775 000 . , BGP, , . CIDR , , . CIDR , . CIDR IP, , , , . CIDR , , IP. CIDR . , . . , . .

1. 67

. .

/16 /24 , IP-, . , , 172.24.0.0/16, 256 , 192.200.0.0/16. CIDR 192.201.1.0/24. , IP- , IP- . IP. , IP-. , IP- 172.24.0.0/16, CIDR, , 172.24.0.0 255.255.0.0. /16 , 16 , . . 1.15 , CIDR .

: 198.32.1.0 255.255.255.0 255.255.0.0

24 16 1100011000100000 00000001 00000000

I

I

11111111 11111111 11111111 11111111

1 1 1 1 1 1 1 1 00000000 00000000 00000000

198.32.1.0255.255.255.0 198.32.1.0/24 198.32.0.0 255.255.0.0 198.32.0.0/16 . 1.15. CIDR

CIDR , IP , . , 200.34.5.0, , 255.255.255.0. , CIDR 200.34.0.0/16. , 24 , CIDR 16 ( 16 24), , , . , IP, .

68

I. OSPF ...

CIDR , 2 0 0 . 3 4 . 5 . 0 , 2 0 0 . 3 4 . 6 . 0 2 0 0 . 3 4 . 7 . 0 ; . , . . 1.16 , CIDR . > I - - . < >

--

131.20.0.0/22 = 10000011.00010100.00000000.00000000 < VLSM

. 1.16. , CIDR

IP IP , (, ). ip classless , - , , . Cisco IOS 12.0 , IP . IP, , , , . , , , , . , , .

CIDR . 1.10 , CIDR .

1.10. > CIDR , , , , , ; .. . CIDR/1 /2 /3

ul i ^ l u l^ ^ii . k Li s lil 127.255.255.255

128.0.0.0 192.0.0.0 224.0.0.0

63.255.255.25531 .255.255.255

1.

69

. 1.10 CIDR 240.0.0.0 248.0.0.0 252.0.0.0 254.0.0.0 255.0.0.0 255.128.0.0 255.192.0.0 255.224.0.0 255.240.0.0 255.248.0.0 255.252.0.0 255.254.0.0 255.255.0.0 255.255.128.0 255.255.192.0 255.255.224.0 255.255.240.0 255.255.248.0 255.255.252.0 255.255.254.0 255.255.255.0 255.255.255.128 255.255.255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252 255.255.255.254 255.255.255.255 15.255.255.255 7.255.255.255 3.255.255.255 1.255.255.255 0.255.255.255 0.127.255.255 0.63.255.255 0.31.255.255 0.15.255.255 0.7.255.255 0.3.255.255 0.1.255.255 0.0.255.255 0.0.127.255 0.0.63.255 0.0.31.255 0.0.15.255 0.0.7.255 0.0.3.255 0.0.1.255 0.0.0.255 0.0.0.127 0.0.0.63 0.0.0.31 0.0.0.15 0.0.0.7 0.0.0.3 0.0.0.1 0.0.0.0

/4 /5 /6

/8 /9

/10 /11 /12 /13 /14 /15 /16 /17 /18 /19 /20 /21 /22 /23 /24 /25 /26 /27 /28 /29 /30 /31 /32

IP CIDR IP CIDR , 5 : 166.38.0.0/19 IP CIDR , .

70

I. OSPF ...

1. 32 . 2. 19 . 3. 16 , 3 . , . 1.11.

7

1 ^' {144^sUjtr^"1*

5

4

2

1

128X

64X

32X

16 1

8 1

4 1

2 1

1 1

4. , : 16 + 8 + 4 + 2 + 1 = 31. 5. ( 31) ( 0), (0+31=31). 6. , CIDR 166.38.0.0166.38.31.255.

: VLSM 1987 . RFC 1009. , , , . , IP , , () . , VLSM . , IP-, . /16, , /22, 64 (26), , 1022 (210 - 2), . 1.17.

131.20.0.0/22 =

foooooTi"6ooi 01 o6.boooob DO.OOOOOOOO

. 1.17. , VLSM

1. 71

, , , 20 30 . , , , 20 30 22 . IP- . , , . , , , VLSM. , , . 1.17, 130.5.0.0/16 , /26 (. 1.18). ^ ^ 1

131.20.0.0/26 = 10000011.000101

OO.DOOOOOOO.OODOOOOO

VLSM

. 1.18. VLSM /16 , /26, 1024 (2 ), , 62 (26 - 2). /26 , 60 , /22 , 1000 . , VLSM, , , . , IP- , .

VLSM , , . , , . , , . . 1.19 11.0.0.0/8, , /16, 11.1.0.0/16 ,

72

I. OSPF ...

/24, 11.254.0.0/16 , /19. , . , , .11.1.1.32/27 11.1.1.64/27 11.1.1.96/27 11.1.1.128/27 11.1.1.160/27 11.1.1.192/27

11.1.1.0/24 11.1.2.0/24 11.1.0.0/16 11.2.0.0/16 11.3.0.0/16 11.1.252.0/24 11.1.253.0/24 11.0.0.0/8 11.1.254.0/24 11.1.3.0/24

11.252.0.0/16 11.253.0.0/16 11.254.0.0/16 - 254.32.0/19 ^11.254.64.0/19 ^^11.254.96.0/19 1.254.128.0/19 1.254.160.0/19 1.254.192.0/19

. 1.19. VLSM

. 1.20 , VLSM IP-. , F G ( 11.1.1.0/24 11.1.2.0/24) (11.254.0.0/26) . , (11.1.0.0/16) , . , , VLSM Internet 11.0.0.0/8 ( 11/8).

, . . , -

1. 73

OSI. TCP/IP, Internet.

11.0.0.0/8

11.254.32.0 11.254.64.0 11.254.192.0

11.1.1.0/24 11.1.2.0/24 11.1.253.0/24 11.1.254.0/24

11.254.32.0/19

F .1.64/27 . 1.2.64/27"v

11.1.1.32/27

^ ^

11.1.2.32/27

11.1.1.96/27 11.1.1.128/27 11.1.1.160/27 11.1.1.192/27

11.1.2.96/27 11.1.2.128/27 11.1.2.160/27 11.1.2.192/27

/. 7.20. VLSM , IP, . , IP-: , VLSM CIDR. , , .

74

I. OSPF...

... ^1| Jjf jj |[ !!*' jjj I ^ OSPF 1 ii . , : ! ^^^ ''-"-7' 'W? ^/00^*"'

^104111

OSPF

^^^: ^ ||^ ^ : ^ OSPF ^

*

4

4

2

OSPF

" SPF (Open Shortest Path First OSPF) . " , . , OSPF . OSPF, |5 , . ; , . , , OSPF . . , , OSPF . . . rjf , , . , . , 1 , OSPF . , , . . .

V'-'*,V 14 --

?,

,

,:

',,\

IF ' . *?. ,'',< .' wI,.? T* * -

1 " " " " .-'

OSPF . (Shortest Path First SPF) , OSPF. SPF OSPF, OSPF. OSPF , SPF. OSPF. . . . . , OSPF. . OSPF. OSPF . , OSPF , , . OSPF . , , OSPF .

. , (Request For Comments RFC). , . , , OSPF, RFC 2328.

RFC Web-:

www.isi.edu/in-notes/rfcxxxx.txt

RFC. RFC, Web-: www.rfc-editor.org/cgi-bin/rfcsearch.pi 78 I. OSPF...

OSPF , . , , . . , , , . , , ; , .

. , , ( ), . , ; . OSPF , OSPF, . , . . . , . , , . (Internet Protocol IP); AppleTalk DECnet. , . . , . . . OSPF, IGRP RIP (Routing Information Protocol ).

, IP, . , OSPF, , IP, , . , , IP

2. OSPF

79

, OSPF RIP. , . , . ( ) , . , . , . .

, , . . , , , . , ? . . . , . , , . . 2.1 , . , . , , . (. . 2.1). , OSPF. (default route). ( ) , , , . , ,

80

I. OSPF...

, (gateway of last resort). . 2.2 , . iproute 192.168.254.0255.255.225.010.10.2.1

OSPF""""**^

10.10.2.2

ip route O.O.O.O 0.0.0.010.10.2.2

. 2.1. OSPF

. 2.2.

. 2.2, , 192.168.254.0/24, SO . . , , , . , . . , , .

2. OSPF

81

, . , , , . , , . , , , .

- , TCP/IP, RIP OSPF. , ( ) , .

, , - (Interior Gateway Protocol IGP); , OSPF BGP (Border Gateway Protocol ). OSPF/BGP 7. IGP , (Autonomous System AS). IGP IGRP, OSPF, IS-IS RIP. IGP (Exterior Gateway Protocol EGP), BGP.

( ) ( ). , , . , . , 82 I. OSPF...

- . , , , . . , . , , . , , , . ATM (Asynchronous Transfer Mode ) , 50 OSPF . , (SPF), (Dijkstra). " SPF", , SPF . , , , , ; . . "" , , . ( LSA) , . SPF.

, , , . . , . . . . , .

2. OSPF

83

, , . SPF , . . 2.3 , . LSA

(LSDB)

SPF

"""

. ,

. 2.3.

, OSPF, . , , .

OSPFOSPF , , . , SPF . OSPF :

84

I. OSPF...

TCP/IP, IP, , RIP, ; , ; RIP, .

" " , " ", , , ! , OSPF RIP , , . , , , OSPF , RIP. , RIP 25 ; , OSPF LSA , , . () OSPF , , , RIP. , LSA , , OSPF EGP. OSPF BGP. , SPF , IS-IS. , , IS-IS OSPF.

IS-IS OSI, , DECnet/OSI (DECnet Phase V), DEC (Digital Equipment Corporation). , , . (ISO) OSI :

2. OSPF

85

IS-IS;

ES-IS (End System-to-Intermediate System ); IDRP (InterDomain Routing Protocol ).

IDRP ES-IS RFC, www.ietf.org. ISO IS-IS, , (ConnectionLess Network Protocol CLNP), ISO, X3S3.3 ( ) ANSI (American National Standards Institute ). IS-IS, CLNP, IP. IS-IS; . OSI ISO; , IS-IS. ISO 10589. Standards definition for IS-IS. RFC 1195. Intermediate IS-IS.

- - , , , . "" , , , , . - - (Bellman-Ford), , .. ; , (Fulkerson). - ( -) , , . .. . 2.4. . 2.4, , ( ). , ; , .

86

I. OSPF...

-

. 2.4. -

RIP 1 - , (Berkeley) 1960- , . , , . RIP : 30 ; , , 15 ; , RIP, , .

RIP , OSPF, RIP 1 2 . 5 Jeff Doyle. Routing TCP/IP, Volume I, RIP. www.cisco.com/univercd/cc/td/doc/cisintwk/ito_docXrip.htm RFC 2453, RIP Version 2, 1998 .

(RIP) cisco. com:

2. OSPF

87

, - . , - . () , . , , , , . , . , - . . . , , .

. , , IS-IS OSPF. , . . , . , . . , . . , . .

88

I. OSPF...

. 2.1 , . 2.1. OSPF IS-IS

IP- IP

IP

IP, ISO, CL.NP ( 2 OSI)

, : AppleTalk RTMP (Routing Table Maintenance Protocol ), IPX (Internetwork Packet Exchange ) Novell RIP, IP RIP, IGRP OSPF. , , . , . . OSPF TCP/IP. TCP/IP , . , , . IS-IS , . IS-IS IS-IS, OSI CLNP, TCP/IP. , IS-IS , .

. , . .

2. OSPF

89

SPF. . OSPF , () ( ). OSPF , ( 0) . OSPF , , . OSPF , . , . , . SPF , . IS-IS , OSPF. , . , IS-IS, , , , IS-IS 2. OSPF, , , . OSPF (Area Border Router ABR) , . IS-IS , . IS-IS . , IS-IS , , , . , Internet IS-IS, Internet OSPF.

IP- IP-. , . , . , , . , .

90

I. OSPF...

, , ( , ..).

, OSPF ISIS, , . . .

IPOSPF , TCP/IP IP. , IS-IS , OSI, , OSI, ISO. IS-IS IP, .

. , , - , . OSPF , ( ), , , . , , OSPF, OSPF Working Group IETF. . IS-IS , OSPF, , . IS-IS Internet, . IS-IS ISO, IP. , , OSPF, IS-IS, .

. 2.2 , .

2. OSPF

91

2.2. : : | i | OSPF VLSM CIDR IS-IS

, ,

, ,

0-65 535 , LSA

0-1023

,

, . 1. . 2. . 3. . IS-IS OSPF . , , ( ), . , , ( , ). , . . OSPF, IS-IS . , , -

92

I. OSPF...

, () . OSPF IS-IS 2 . , , .

. , . . (RIP, OSPF IS-IS) . , . , . RIP 30 , OSPF 30 , IS-IS 15 . . OSPF IS-IS , . . RIP . OSPF IS-IS , . , .

VLSM CIDR OSPF IS-IS (VLSM) (CIDR). VLSM . , VLSM CIDR .

. : . , Cisco,

2. OSPF

93

, . OSPF , , OSPF .

, . : , , . OSPF , 16 . OSPF 0 65 535. OSPF , FDDI (Fiber Distributed Data Interface - ) 1. OSPF . IS-IS . 0 1023. 1S-IS 10. , , . IS-IS .

ISO 10589, IS-IS 100 400 2. , -, , , , , , ATM , . OSPF, , . , , .

OSPF, IS-IS . IS-IS (NonBroadcast MultiAccess NBMA), , NBMA ; . OSPF , Cisco .

94

I. OSPF...

. OSPF , LSA, , , OSPF LSA. IS-IS LSA , . , (MPLS), .

. 2.3 , . 2.3. , , ^ j-^j a. - *&^ jtu ^ >, '.* T"^? l^L?...! J>.^**.S^.\.j^*j^J!Ai>fj{ ? * * i ^?;*-. "ff jl' 'L.-J*-i*?^? f V k

IS-IS , ,

OSPF

, . , . , , . OSPF , IETF RIP. OSPF RFC 2328. IS-IS , ISO ISO 10589. ISIS IS-IS. IETF Internet (Internet Draft).

, , , . , ,

2. OSPF

95

. , , . . OSPF IS-IS , , : OSPF; IS-IS .

, OSPF . , , , . IS-IS Cisco . OSPF , IS-IS , OSI, TCP/IP. , IS-IS DECnet Phase V.

IS-IS Abe Martey. /S-/S Network Design Solutions, Cisco Press.

SPFOSPF . , SPF . , OSPF.

OSPF . , , , . IP- , , . , SPF. , ; , .

96

I. OSPF...

ARPAnet. . , ARPAnet ( , ).

SPF ARPAnet - . RIP , . , RIP, . , ( ) , . 1 OSPF, RFC 1131 1989 OSPF Working Group IETF. OSPF . , . 1956 , 30 , OSPF, ARMAC. . (Edsger W. Dijkstra) 1930 , . , , , 1959 . 32 , . . , , . , , . , . . , . . . , , .

2. OSPF

97

( ), . , ( ) , , ( ), . , () . , , . ( ) () () , . , , . , , 50 , 100. OSPF, , , , OSPF. SPF (. 2.5). , ( ).

____

. 2.5. SPF

1. , (). ( ), , ( ).

98

I. OSPF...

2. . ( OSPF) , . X 100, . , . ; 100; X; .

3. , X, , . OSPF : ; 100; Y; . ; 100; Z; .

, , . 4. , Y, , ; , . D; 50; ; .

5. , Z. ; 100; ; .

6. , SPF , . 7. OSPF . ( , , , , , .) , . ; ; ; D; ; 100; X; . 100; Y; . 100; Z; . 50; ; . 100; ; .

OSPF , , , . , , . SPF, OSPF. 8. OSPF SPF . , ( ), () () (. 2.6). , , .

2. OSPF

99

, , . 1: (100) + (100) + D (50) = (250) 2: (100) + (100) + (100) = (300) , SPF, , , ( ). SPF , 1, 2. 9. , 1.

. 2.6. SPF

10. 1 ( ), , ( ) . , SPF . , . , X , . SPF () , Z. , , , .

, . , -

100

I. OSPF...

. , . : , , . , . , OSPF (*1 ) , . - , O(N*M) , N .

SPF, (. 2.7) . RTA, . RTA 192.168.254.0 192.168.254.0 192.168.254.0 : 5

*: 5 10.10.10.0 : 10 | : to

: 5 100.100.100.0

SPF

15

. 2.7. , , SPF

2. OSPF

101

. 2.7 , , RTA. . , RTB 192.168.254.0 10.10.10.0. RTA 10.10.10.0 RTB 15 (10+5). , RTA 100.100.100.0 RTC, 20 (10+10), RTB, 20 (10+5+5). , , OSPF Cisco , . . (), , , . OSPF , , OSPF. , , . ( ), OSPF, . . (SPF). . .

OSPF. . . , . ( Of Service - TOS). . . . : ; ; . .

102 I. OSPF...

. . . VLSM CIDR

SPF SPF, Cisco Systems, . SPF . SPF . SPF , (LSA), , LSA. LSA SPF. OSPF , SPF , LSA. , SPF , , LSA. , SPF , , IP. IP SPF.

SPF , , OSPF. , SPF LSA. OSPF , show ip ospf process id. SPF. - , , . 2.1 show ip ospf, SPF. . . . . . . , { 2.1. show ip ospfHAL9000#show ip ospf 100

Routing Process "ospf 100" with ID 10.10.10.10 Supports only single TOS(TOSO) routes SPF schedule delay 5 sees, Hold time between two SPFs 10 sees Number of DCbitless external LSA 0 Number of DoNotAge external LSA 0 Number of areas in this router is 1. 1 normal 0 stub 0 nssa

2. OSPF

103

Area BACKBONE(0) (Inactive) Number of interfaces in this area is 1 Area has no authentication SPF algorithm executed 13 times Area ranges are Link State Update Interval is 00:30:00 and due in 00:09:05 Link State Age Interval is 00:20:00 and due in 00:19:05 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 HAL9000*

, SPF debug ip ospf spf inter debug ip ospf spf external, , LSA. , LSA LSA.

OSPF OSPF . OSPF , : OSPF ; , , , .

, , . . , . ARIN , RIPE APNIC . OSPF , , Internet, Internet, . . , . , , . , .

104

I. OSPF...

OSPF , . , , . (. ). 30 100. ( .) 0, (ABR) . , ABR, .

Cisco Systems , . , . , , .

OSPF OSPF : ; . .

. , OSPF.

, OSPF, . OSPF LSA, ( 1) ( 2). , OSPF , "".

2. OSPF

105

OSPF ; ' , OSPF...

, OSPF. (Autonomous System Boundary Router ASBR) , . , .

ASBR, ip ospf summaryaddress, . Cisco . , OSPF, . 1. 1 ( ) OSPF. , , 1 OSPF. OSPF 1. 2. 2 , OSPF . OSPF; , , . , , 2 , .

, : , , 1 2.

OSPF , . , , . OSPF , . , , . SPF. , .

2. OSPF

107

, OSPF . , , , OSPF . , LSA , . . , , , . , , , OSPF.

OSPF OSPF : ; SPF; , , 0 ; , , .

OSPF : , 0; , ; ;

.

0: OSPF . , . , ;

108

I. OSPF...

. 4.

, , , . : . ABR. , . , OSPF. . , , OSPF . , ABR LSA 4 5. . . . , ABR (0.0.0.0). ABR; . ABR , , .

OSPF, , , , , , , OSPF, , OSPF. ( ), 0. , , . , , , . , , .

2. OSPF

109

. , , . . ASBR . OSPF , . LSA 4 5.

. Cisco Systems , , no-summary , . , ( ). , , , . . . 0.

(Not-So-Stubby Area NSSA) RFC 1587, The OSPF NSSA Option. NSSA Internet , , . NSSA OSPF . , NSSA RFC. LSA ( 7). OSPF ( ) LSA . NSSA , Internet RIP, OSPF. NSSA , ( ) OSPF, RIP. NSSA . 2.8.

110

I. OSPF...

1

. ABR

OSPF

- ABR NSSA OSPF ASBR

NSSA

. 2.8. NSSA

OSPF OSPF. , OSPF, . , OSPF , . RFC 1793, Extending OSPF to Support Demand Circuits, , , OSPF , . RFC, OSPF , ISDN. , , , , . , , OSPF.

OSPF OSPF , OSPF. . . 2.9 OSPF, OSPF . OSPF .

(Internal Router IR) , , OSPF. , .

2. OSPF

111

2

3 .'' OSPF

; ABR

(AS) IR ABR BR ASBR

. 2.9. OSPF

ABR OSPF, ABR . ABR . ABR , , . ABR , OSPF ; OSPF, , . ABR , , . ABR LSA ABR , .

ASBR , . ASBR . , -

112

I. OSPF...

ASBR . ASBR OSPF , RIP . ASBR OSPF, .

Cisco redistribution. BGP. Sam Halabi. Internet Routing Architectures, Second Edition. ASBR . OSPF ASBR redistribute static redistribute connected OSPF.

(Backbone Router BR) , . BR , OSPF, ABR.

OSPF . 2.10 , OSPF. OSPF (. 2.10) . . , OSPF , Ethernet FDDI. OSPF; (Designated Router DR) (Backup Designated Router BDR).

2. OSPF

113

NBMA

. 2.10. OSPF

OSPF, , , . (NBMA). NBMA . Frame Relay, ATM .25. NBMA , , . . NBMA, OSPF , , NBMA. DR BDR, . . , OSPF, -

114

I. OSPF...

. , (Point-to-Point Protocol "-") HDLC (High-Level Data Link Control ). DR BDR. OSPF , 2.3. | 2.3. OSPFHAL9000(config-i) #ip ospf network ? broadcast Specify OSPF broadcast multi-access network

non-broadcastpoint-to-multipoint point-to-point

Specify OSPF NBMA networkSpecify OSPF point-to-multipoint network Specify OSPF point-to-point network

, OSPF, (Router ID RID). 32- , , . RID (Link-State DataBase LSDB) OSPF , . OSPF. , RID OSPF. RID OSPF . 1. , RID ospf router-id. 2. 2. , IP- . , IP-. , . 3. RID IP- . Cisco IP-, . , , , .

2. OSPF

115

, , , IP- . , IP-.

IP- , "" IP- . IP-, , IP- . RFC 1918.

OSPF , , , . OSPF , , . , . 10 30 NBMA. 224.0.0.5 ( AllSPFRouters SPF); , OSPF, . , , , RID : - - ; ; ( ); ( ); .

2.4 , , . HAL9000 , .

116

I. OSPF...

2.4. HAL9000#show ip oapf neighbor

Neighbor ID Pri 192.168.254. 102 1 1 192.168.254. 100 192.168.254. 101 1HAL9000#

State FULL/BDR FULL/DROTHER FULL/BROTHER

Dead Time00 :00 :37 00 :00 :32 00 :00 :34

Address 192 .168,.254. .102 192 .168..254. .100 192 .168..254. ,101

Interface EthernetO EthernetO EthernetO

OSPF , . priority, , DR, DR ip ospf priority.

OSPF . . . , OSPF . . .

DR. DR.

BDR. BDR. , , , . 3.

OSPF , , , . , . . , . , .

2. OSPF

117

, , . : , .. , . OSPF. , , show ip ospf interface, 2.5. I 2.5. [ HAL9000#show ip ospf interface EthernetO is up, line protocol is up Internet Address 192.168.254.253/24, Area 0 Process ID 100, Router ID 192.168.254.253, Network Type BROADCAST, Cost: 10 Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 192.168.254.253, Interface address 192.168.254.253 Backup Designated router (ID) 192.168.254.102, Interface address 192.168.254.102 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:06 Neighbor Count is 3, Adjacent neighbor'count is 3 ,. Adjacent with.neighbor.192.168.254.102 ;; (Backup Designated Router) Adjacent,with neighbor 192,168,254,100 Adjacent with neighbori!92.168.254.101 Suppress hello for 0 neighbor(s) SerialO is down, line protocol is down OSPF not enabled on this interface HAL9000*

i

OSPF , . OSPF, NBMA , . , , , , , . (DR). OSPF , . : = [ * (-1)]/2,

, .

118 I. OSPF...

, , 5 . :[5 * (5-1)]/2 = 10 .

, 10 . :[10 * (10-1)]/2 = 45 .

, DR . DR . OSPF. DR , , , . , DR . , OSPF , DR.

DR , DR. , ; RFC 2328.

. 2.11 , DR BDR. , . 2.11, . 1. OSPF , ( ) . , . , . 2. , DR. , OSPF 0. , , . , . 3. BDR , . , OSPF . 4. , . DR , - .

2. OSPF

119

. OSPF DR,

?

DR

, '

BDR

BDR

DR ?

. 2.11. DR

5. DR, DR BDR. 6. DR, , BDR. , DR, , 3. , DR, BDR. , DR OSPF . , DR, , , DR, BDR BDR, DROther.

120

I. OSPF...

7. DR .

: OSPF , , . , OSPF. , , OSPF . . 2.122.15 , . 1. OSPF. 2. 224.0.0.5, OSPF. , DR (. 2.12).

. 2.12.

DR, DR, .

3. DR BDR , . (. 2.13).

2. OSPF

121

DR

BDR

. 2.13. DR BDR

4. DR BDR DR LSA ( 1) . BDR , DR, , DR (. 2.14).

LSA gpp (LSA 1)

. 2.14. LSA

5. BDR , , DR.

122

I. OSPF...

LSA ( 2 2 4 . 0 . 0 . 5 ) , , . , DR , (. 2.15). DR, BDR BDR.BDR

LSA

LSA DR. 2.15. LSA

. , . OSPF , DR BDR. , , , , DR BDR. ip ospf priority, . , . 1, , , DR BDR. , DR; , .

( , , ).

2. OSPF

123

, , 5, :interface ethernet ip ospf priority 5

, , OSPF, , DR BDR. , DR BDR , . OSPF, DR BDR. , DROther; , DR BDR, . , , DR BDR, ; , .

: , OSPF LSA. , LSA . . 2.16 OSPF . 0 OSPF HAL9000 / 30 OSPF \ .../24faO/1

/Tokyo\

', 10 OSPF ' \ 20 OSPF .' 10.10.10./24 / \ 20.20.20./24

. 2.16. OSPF,

2.6 HAL9000, show ip ospf database.

124

I. OSPF...

; 2.6. LSA " HAL9000.' , . . * 1.

HAL9000#*how ip ospf database

OSPF Router with ID (192.168.254.253) (Process ID 100) Router Link-states (Area 0) Link ID ADV Router Age Seq# Checksum 192.168.254.100 192.168.254.100 649 0x80000003 Ox75C 192.168.254.101 192.168.254.101 651 0x80000003 Ox55B 192.168.254.102 192.168.254.102 582 OxSOOOOOOA OXF461 0x80000051 0x0669 192.168.254.253 192.168.254.253 1486 Net Link-states (Area 0) Link ID ADV Router Age Seq# Checksum 0x80000006 OX355B 192.168.254.253 192.168.254.253 1346 Summary Net Link-states (Area 0)Link ID 10.10.10.0 20.20.20.0 30.30.30.0 HAL9000* ADV Router 192.168.254.102 192.168.254.100 192.168.254.101 Age 648 1312 651 Seq# Checksum 0x80000002 OXBC91 0x80000001 Ox61Dl 0x80000002 OxEF23

Link count 1 1 1 1

, , , . 2.16. , HAL9000 , , 0. 2.6, HAL9000, 2.7, Tokyo.

2.7. LSA Tokyo^^^-^'.''~^^-( ' ''.>*'':" -'---' ' ' ' ' ;

, .

Tokyo* show ip oepf database

with. ID (192.168.254.101) (Process ID 100) 'Link-states (Area 0)i &**'.iff ADV 'Router . Age Seq# '' ; Checksum Link count 192.168.254 192.168.254.100 903 0x80000003 Ox75C 1 192.168.254.101 192.168.254.101 903 0x80000003 Ox55B 1 192.168.254.102 192.168.254.102 836 OxSOOOOOOA OxF461 1 192.168.254.253 192.168.254.253 1740 0x80000051 0x0669 1 Net Link-states (Area 0) Link ID ADV Router Age Seq# Checksum 192.168.254.253 192.168.254.253 1601 0x80000006 Ox355B Summary Net Link-states (Area 0) Link ID ADV Router Age Seq# Checksum 10.10.10.0 192.168.254.102 902 0x80000002 OxBC91 20.20.20.0 192.168.254.100 1567 0x80000001 Ox61Dl 30.30.30.0 192.168.254.101 904 0x80000002 OxEF23 Router Link-states (Area 30) Link ID ADV Router Age Seq# Checksum Link count 192.168.254.101 192.168.254.101 904 0x80000002 1 Summary Net Link-states (Area 30) Link ID ADV Router Age Seq# Checksum 10.10.10.0 192.168.254.101 826 0x80000005 OxC684 20.20.20.0 192.168.254.101 1566 0x80000001 Ox65CB 192.168.254.0 192.168.254.101 1421 0x80000007 Ox7B84 Tokyo*

2. OSPF

125

. , RFC 2328 OSPF 2 . , 2.7, LSA, . . Cisco , , LSA. , RID, OSPF . Cisco OSPF. , . , ABR (LSDB) OSPF. , LSA OSPF LSDB. , . Link ID ( ). RID , LSA. ADV Router ( ). RID , LSA. Age (). LSA . Seq# ( ). LSA, LSA, . Checksum ( ). , LSA. Link count ( ). , , OSPF, , LSA. LSA ( 1). . 2.17 , OSPF. , , ( ). , . , RtrA RtrE, , 4. RtrE RtrA 5. .

126

I. OSPF...

0 OSPF

- - 10/ - 100 /

. 2.17. OSPF

OSPF, , , . 2.17. , OSPF, . 0.

, , . 2.17, : RtrA RA, RtrB RB .. . 2.4 OSPF . 2.17. , , . 2.17. . , OSPF , . , , , (.. ). .

2. OSPF

127

, RtrA (RA). , D . 2, 4 ..

I 2.4. , | i OSPF 2 * , ..xiU ' '' \\ - j -* . *.... .. \ * .. . ' ' '."'"..> .. ' . ' > . V "''.,. ., . ' . t. 1

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RB RD RE RA RC RE RB RF RA RE RG RA RB RD RF RQ RH RC RE RH RE RE RF

24 4

2110

5

24 3 5 5

23

21 8

2 24 1 8 6

. . , OSPF. , , . 2.4. . 1. SPF , SPF (. . 2.6). , 0.

128 I. OSPF...

2. , , .

, OSPF SPF, .

3. . ( ), . , .

SPF . .

4. RID , , . , , , , . 5. , 3. , SPF . SPF , OSPF. . 2.5 , , . 2.17. 2.5. SPF , : . 2.4 ' ","' ', ...;.,>>;..: '. .'!,'. , /',' i.-.,'-,;'..:

RA,RA,0

RA SPF

2. OSPF

129

. 2.5 244

RA,RB,2 RA,RD,4 RA,RE,4 RA,RD,4 RA,RE,4 RB,RC,1 RB,RE,10 RD,RE,7

RA,RA,0

RA (RA,RB,2) , . RB, , . , RE . (RA,RE,4) RE (RB,RE,10) (RD,RE,7), (RB,RC,1) , . RC, , (RA.RD.4), (RA,RE,4), RA, 4; (RC,RF,2) 5. (RA.RD.4) , . RE; (RD,RE,3) , , RA,

443

RA,RA,0 RA,RB,2

RA,RD,4 RA,RE,4 RC,RF,2

445

RA,RA,0 RA,RB,2 RB,RC,1

RA,RE,4 RC,RF,2 RD,RE,3 RD,RG,5

4579

RA,RA,0 RA,RB,2 RB.RC.1 RA,RD,4

130

I. OSPF...

. 2.5 596512

RC,RF,2 RD,RG,5 RE,RF,2 RE,RG,1 RE,RH,8

RA.RA.O RA.RB.2 RB,RC,1 RA,RD,4 RA,RE,4

(RF,RE,1) . RE, . RG (RC,RF,2) , RF. (RE,RG,1), (5) , RA. RH (RE,RG,1). RG , , (RF,RH,4) , . , . , RA ,

RE.RF.2 RE,RG,1 RE,RH,8 RF.RH.4

65129

RA,RA,0 RA,RB,2 RB,RC,1 RA,RD,4 RA,RE,4 RC,RF,2

RF,RH,4

RA.RA.O RA,RB,2 RB,RC,1 RA,RD,4 RA.RE.4 RC,RF,2DC 1

RA.RA.O RA,RB,2 RB,RC,1 RA,RD,4 RA,RE,4 RC,RF,2 RE,RG,1 RF,RH,4

. 2.5 , .

2. OSPF

131

; . . , RtrA, . 2.17, SPF , . 2.5. . 2.18 , RtrA . , . .

. 2.18. SPF

: OSPF . , , , OSPF. , MatrixNet, , , OSPF . , Ethernet, , . 2.19. OSPF Cisco. , OSPF . OSPF OSPF .

132

I. OSPF...

. 2.19. OSPF MatrixNet

OSPF , IP- . . , , RID. 2.8 Neo, Cypher . [ 2.8. Neo(config) tinterface loONeo(config-if)#ip address 192.168.254.82 255.255.255.0 Cypher (config) tinterface loO Cypher(config-if)#ip address 192.168.254.83 255.255.255.0

Apoc(config)#interface loOApoc c o n f i g - i f ) # i p address 192.168.254.84 255.255.255.0

OSPF OSPF. , 2.9.

2. OSPF

133

2.9. OSPFNeolconfig)#router ospf 100 Neolconfig-router)^network 192.168.254.0 0.0.0.255 area 0 Neofconfig-router)ttnetwork 10.0.0.0 0.0.0.127 area 0

OSPF OSPF show, 2.10. 2.10. OPSFNeotshow ip protocols Routing Protocol is "ospf 100" Sending updates every 0 seconds Invalid after 0 seconds, hold down 0, flushed after 0 Outgoing update filter list for all interfaces is Incoming update filter list for all interfaces is Redistributing: ospf 100 Routing for Networks: 10.0.0.0/25 192.168.254.0 201.0.0.0/25 Routing Information Sources: Gateway Distance Last Update 192.168.254.84 110 03:09:43 192.168.254.83 110 /.,03:09:43 Distance: (default is 110)

|

OSPF . , , OSPF, RID , . 2.11, show ip ospf , , OSPF , . 2.11. show ip ospfNeotshow ip ospf Routing Process "ospf 100" with ID 192.168.254.82 Supports only single TOS(TOSO) routes Supports opaque LSA It is an area border router SPF schedule delay 5 sees, Hold time between two SPFs 10 sees Minimum LSA interval 5 sees. Minimum LSA arrival 1 sees Number of external LSA 0. Checksum Sum 0x0 Number of opaque AS LSA 0. Checksum Sum 0x0 Number of DCbitless external and opaque AS LSA 0 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 2. 1 normal 1 stub 0 nssa

134 I. OSPF...

External flood list length 0 Area BACKBONE (0) Number of interfaces in this area is 2 Area has no authentication SPF algorithm executed 15 times Area ranges are Number of LSA 4. Checksum Sum Oxl58A8 Number of opaque link LSA 0. Checksum Sum 0x0 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0 Area 201 Number of interfaces in this area is 1 It is a stub area generates stub default route with cost 1 Area has no authentication , ' .- SPF algorithm executed 7 times *>' Area ranges are 100.0.0.0/16 Passive Advertise 201.0.0.0/16 Passive Advertise Number of LSA 6. Checksum Sum Ox42B44 Number of opaque link LSA 0. Checksum Sum 0x0 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0

show OSPF , , . , RID OSPF (192.168.254.82); IP- , , 2.8. , OSPF (, ABR). , SPF (, OSPF LSDB ). , OSPF . , ( Neo) . 2.12 , show ip ospf neighbor. 2.12. OSPF Neo#show ip ospf neighbor Neighbor ID 192.168.254.83 192.168.254.84 Neo*Pri 1 1

StateFULL/DROTHER FULL/BDR

Dead Time 00:00:38 00:00:37

Address 10.0.0.1 10.0.0.2

Interface FastEthernetO/0 FastEthernetO/0

2. OSPF

135

: RID Neo; ( 3); IP- , Neo OSPF; .

, . State. , Neo ; FULL. State , . , 192.168.254.84 BDR , 192.168.254.83 , DROTHER (.. , DR). , DR? show ip ospf neighbor, 2.13, . 2.13. OSPF Neo#show ip ospf neighbor detail Neighbor 192.168.254.,83, interface address 10.0.0.1 In the area 0 via interface FastEthernetO/0 Neighbor priority is 1, State is FULL, 6 state changes DR is 10.0.0.3 BDR is 10.0.0.2 Options is 0x2 Dead timer due in 00:00:33 Index 2/2, retransmission queue length 0, number of retransmission 2 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 1, maximum is 1 Last retransmission scan time is 0 msec, maximum is 0 msec Neighbor 192.168.254.84, interface address 10-0-0.2 In the area 0 via interface FastEthernetO/0 Neighbor priority is 1, State is FULL, 6 state changes DR is 10.0.0.3 BDR is 10.0.0.2 Options is 0x2 Dead timer due in 00:00:39 Index 1/1, retransmission queue length 0, number of retransmission 1 First 0x0(01/0x0(0) Next 0x0(01/0x0(0) Last retransmission scan length is 1, maximum is 1 Last retransmission scan time is 0 msec, maximum is 0 msec Neo#

j i

show ip ospf neighbor detail , OSPF. , , DR BDR, , - OSPF.

136 I. OSPF...

show ip ospf interface , . , OSPF , , . , OSPF . 2.14.

. 2.14. show ip ospf interfaceNeoflshow ip ospf interface faO/0

FastEthernetO/0 is up, line protocol is up Internet Address 10.0.0.3/25, Area 0Process ID 100, Router ID 192.168.254.82, Network Type BROADCAST, Cost: 1

Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 192.168.254.82, Interface address 10.0.0.3 Backup Designated router (ID) 192.168.254.84, Interface address 10.0.0.2 Timer intervals configured. Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:09 Index 1/1, flood queue length 0 Next 0x0(01/0x0(0)Last flood scan length is 0, maximum is 3 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 2, Adjacent neighbor count is 2 Adjacent with neighbor 192.168.254.83 Adjacent with neighbor 192.168.254.84 (Backup Designated Router) Suppress hello for 0 neighbor(s) Neot

, , show ip ospf database. , LSDB OSPF. 2.15 , LSDB Cisco.

2.15. show ip ospf database JNeotshow ip ospf database OSPF Router with ID (192.168.254.82) (Process ID 100)

Router Link States (Area 0) Link ID ADV Router Age1696 1943 1675

Seq#

Checksum Link count2 2 2

192.168.254.82 192.168.254.82 192.168.254.83 192.168.254.83 192.168.254.84 192.168.254.84

0x80000013 Ox6A5A 0x80000000 Ox4E71 OxSOOOOOOD Ox5F5D

Net Link States (Area 0) Link ID 10.0.0.3 ADV Router 192.168.254.82 Age 1951 Seq# Checksum OxSOOOOOOB 0x2090

Router Link States (Area 201)

2. OSPF

137

Link ID 192.168.254.82

ADV Router 192.168.254.82

Age 423

Seqt Checksum Link count OxSOOOOOOF OxDIEE 0

Summary Net Link States (Area 201) Link ID 0.0 .0.0 10. 0.0. 0 192 .168 .254 .82 192 .168 .254 .83 192 .168 .254..84

ADV Router 192. .168..254 .82 192. .168.,254 .82 192. .168.,254 .82 ,254 .82 192.,168. 192..168.,254 .82

Age 1178 1953 1698 1953 1698

Seq# OxSOOOOOOC 0x80000011 OxSOOOOOOB OxSOOOOOOB OxSOOOOOOB

Checksum OxASCF OxlFC9 OxCCFl OxCCEF OxC2F8

, LSDB LSA; 3. , .

, , , IS-IS OSPF. . , OSPF. , , , . " OSPF" , . , , . OSPF , , . OSPF , . OSPF . , OSPF . " OSPF" , OSPF. , . OSPF. : , , , , , OSPF, LSA.

138

I. OSPF...

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. 3.18. OSPF

. NBMA. , , , , - . OSPF : ( ), (, - , - ), , , . ( 1 . 3.17). , , . , , , -

3. OSPF

155

- , . ( 2 . 3.17). OSPF , . , . , - . OSPF DR. , . DR BDR, . (DD) . ( 3 . 3.17). . / , , LSA . (RID) , . DD. , DD . ( 4 . 3.17). DD, , . DD . / . ( 5 . 3.17). , . (. 2) , LSA. . 3.19 , . ( 6 . 3.17). OSPF , . , OSPF . ,

156

I. OSPF...

DR BDR, , , , DR BDR, .0 1 2 3 01234567890123456789012345678901 AuType

LSA . 3.19.

, , . , . DR BDR. . - RouterDeadinterval ( RouterDeadinterval = 4 * Hellolnterval (- )), . LSA . DD; 2, , , . DD , . . 3.20 , DD . DD , , . - LSA, . . /, , , .

3. OSPF

157

0 1 2 3 01234567890123456789012345678901 MTU I MS

AuType

DD

ISA . 3.20.

OSPF OSPF , , OSPF. OSPF IP, , . . . .

.

OSPF OSPF , . OSPF . 3.2. , .

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158

I. OSPF...

. 3.2

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OSPF . . 3.21 ( ), , OSPF ( , ). OSPF , ( 2 2 4 . 0 . 0 . 5 ) , OSPF.0 1 2 3 01234567890123456789012345678901

. 3.21. OSPF OSPF. 2. OSPF ( . 3.2). , . AuType

OSPF, , OSPF, , EIGRP. , . , OSPF , .

3. OSPF

159

() . , . DR BDR NBMA. OSPF (.. ).

. 3.22 , OSPF .

. 3.22.

, 30 (NBMA) 10 . OSPF . 1. OSPF . 2. OSPF . 3. OSPF . OSPF . OSPF Working Group , , OSPF . OSPF , . , , , , OSPF. , OSPF, .

160

I. OSPF...

OSI IP- 2. , Ethernet 23 IP- Ethernet, 0100.5. IP- AllSPFRouters - 0100.5.0005. , , AllSPFRouters 2 ( f f f f . f f f f . f f f f ) . OSPF , .

- ip ospf hello-interval seconds, , , . , CCIE , OSPF - 4 - . - , . OSPF , , - / . -, . HAL9000#show ip ospf interface ethernet 0 EthernetO is up, line protocol is up Internet Address 192.168.254.253/24, Area 0 Process ID 100, Router ID 10.10.10.10, Network Type BROADCAST, Cost: 10 Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 10.10.10.10, Interface address 192.168.254.253 No backup designated router on this network Timer intervals configured. Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:03 Neighbor Count is 0, Adjacent neighbor count is 0 Suppress hello for 0 neighbor(s) HAL9000#

(, Ethernet Token Ring) , , . NBMA ( Frame Relay, X.25 ATM) OSPF , . , -

3. OSPF

161

(. " OSPF" 2). OSPF , OSPF . (.. Frame Relay) OSPF , . , . , , , , ATM, ARP.

OSPF . OSPF 24- , , , . , , . 3.23. 32-, : Hellointerval - (16 ); (8 ); (8 ).0 1 2 3 01234567890123456789012345678901

1

- RtrPri AuType

OSPF

-

. 3.23.

162

I. OSPF...

. . OSPF, , . . . . , OSPF ( IP- ). RID , , IP-. . , , , 32- . . , . OSPF , Ethernet, IP. . , . , . - (Hellointerval). , . (Rtr Pri). , ; , 1. , 0, , BDR DR. - (RouterDeadlnterval). , , . . IP- , ( ). 0 . 0 . 0 . 0 , , . . IP- ( ). 0 . 0 . 0 . 0 , , . . , . .

3. OSPF

163

() OSPF ( ). . (.. , ) OSPF DR. ( ) . , OSPF. , . , . . , . 3.24. 1 ' 2 3 01234567890123456789012345678901 OSPF, 2 (DD) DD LSA LSA LSA LSA OlMMs

. 3.24.

, , . , , .

OSPF . , . LSDB, OSPF. , -

164

I. OSPF...

LSDB OSPF , . (, ) , , ( ), . . , ( ) LSA. OSPF -, . LSA 14 7 ; , LSA . LSA 5 OSPF, NSSA. DR, , DR, DR. DR , . OSPF , ; , LSDB.

OSPF , . , , , , OSPF , . OSPF . - -. , OSPF DR. DR . , DR, . - , - .

. 3.25 , .

3. OSPF

165

0 1 2 3 01234567890123456789012345678901 OSPF, 4 () LSA . 3.25.

LSA Cisco IOS 12.0 , LSA OSPF. Cisco, , , . , OSPF, . , , .

LSA LSA OSPF no LSA OSPF , . .

Cisco LSA OSPF Cisco IOS 12.0 .

LSA OSPF , , LSA . LSA (60 ) . LSA, LSA, . LSA LSA, . OSPF LSA, LSA , , . , LSA,

166

I. OSPF...

30 ; , LSA 60 . 30 , LSA. OSPF LSA 10 . LSA , Cisco IOS LSA -, -. , , 30 LSA, , . . 3.26, LSA . , . LSA. , 120 LSA Ethernet 3

30

30

30

, OSPF, LSA . 3.26. LSA OSPF -

OSPF ( LSA) LSA, . -, LSA , . , LSA . - LSA. , LSA 30 , LSA. , . LSA , , , , , . , LSA, LSA , -. LSA, , , . , -

3. OSPF

167

, . . 3.27 , . , - LSA, , LSA . ,

< - LSA

II II

20 LSA, 1 LSA 4 3 ' LSA, 1

1 5 LSA, 1 14

4

4 4 4 4

. 3.27. LSA OSPF -

LSA OSPF , . . OSPF.

LSA LSA OSPF . - , , , , . - ; 4 , , , . - LSA, , . , 10000 LSA, - . ( 40 100 LSA), - 10 20 .

168

I. OSPF...

- LSA 240 (4 ). - 10 1800 (30 ). - LSA :router ospf 100 timers Isa-group-pacing 60

- OSPF LSA 60 .

OSPF OSPF Cisco IOS 12.0, OSPF , , , . , , . , .

, . OSPF , 33 . - . OSPF . , , LSA . , Cisco IOS, ; . OSPF LSA, , exec-: show ip ospf flood-list

LSA OSPF LSA , , , LSA. OSPF , . , OSPF , , .

3. OSPF

169

, , - . , , OSPF, , . OSPF LSA , : , OSPF; .

, LSA OSPF :ospf database-filter all out

LSA OSPF : router ospf 109 neighbor ip-address database-filter all out

LSA MOSPF Cisco OSPF (Multicast OSPF MOSPF) LSA 6 . MOSPF, , , . : router ospf 109 ignore Isa mospf , MOSPF, router ospf 109 ignore Isa mospf

- LSA Cisco -, LSA, . OSPF, -

170

I. OSPF...

, LSA , , LSA . 5 LSA . . , . ip ospf retransmit-interval , 3.1.

3.1. LSA ; . ;HAL9000(config)#int HAL9000(config-if)#ip ospf ? authentication-key Authentication password (key) cost Interface cost dead-interval Interval after which a neighbor is declared dead demand-circuit OSPF demand circuit hello-interval Time between HELLO packets message-digest-key Message digest authentication password (key) network Network type priority Router priority retransmit-interval Time between retransmitting lost link state advertisements transmit-delay Link state transmit delay HAL9000(config-if)#ip oapf r*tranmit- interval'-?. 1'',', ,,.* ^^End with CNTL/Z.

. OSPF

171

H A L 9 0 0 0 ( c o n f i g - i f ) t i p ospf transmit-delay ? Seconds

, OSPF, , . , OSPF - , , LSDB (.. ). , , . , .

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172

I. OSPF...

. . . . , .

OSPF, , DD. , , , . , DR BDR . . , , . RID. , DD. . LSDB, DD. DD . ( LSA). . , DD , (Link-State Request LSR), , . (.. , LSR) LSA, . . , , LSA.

OSPF. , , . , .

3. OSPF

173

3.4. ". HUB_ROUTER1# interface SerialO ip address 10.0.1.1 255.255.255.0 ip ospf network point-to-multipoint non-broadcast encapsulation frame-relay frame-relay map ip 10.0.1.2 102 frame-relay map ip 10.0.1.3 103 frame-relay map ip 10.0.1.4 104 no shut I router ospf 1 network 10.0.1.0 0.0.0.255 area 0 neighbor 10.0.1.2 neighbor 10.0.1.3 neighbor 10.0.1.4

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HUB_ROUTERl#show frame map SerialO (up): point-to-point dlci, dlci 111(0x12,0x420), broadcast SerialO (up): point-to-point dlci, dlci 222(0x10,0x400), broadcast Se