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, . , , , Border Gateway Protocol (BGP) v4.

, . , , , . : . , .

Merion Academy


, , . , , .


OSPF IS-IS

Intermediate System to Intermediate System (IS-IS IS to IS) 1978 .

Open Shortest Path First (OSPF) IS-IS, IPv4. 1989 OSPF Internet Engineering Task Force, OSPFv2, , 1998 RFC2328. OSPF, , , IS-IS . , ( ).

1993 Novell, , IS-IS Netware. Novell, Internet Packet Exchange (IPX), , (EIGRP, IPX). IS-IS. Novell, IS-IS, . IS-IS -, , RIP, IS-IS OSPF.


Intermediate System to Intermediate System Protocol

Intermediate System to Intermediate System (IS-IS) Intermediate System ( (IS), - End System ( (ES). , , , . (Network Service Access Point - NSAP), . , IP, IS-IS . End System to Intermediate System (ES-IS), IS-IS , , .

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


OSI

IS-IS , Internet Protocol (IP) . (Open Systems Interconnect - OSI) , . OSI , , , , , , (N-). OSI , . IP .

  • Authority Format Identifier (AFI), Initial Domain Identifier (IDI), High-Order Domain Specific Part (HO-DSP) , .
  • - .
  • N Selector, NSAP, ( , NSAP, ).

, , 1.

1:

  • . , , .
  • N- , . , A N-, 49.0011.2222.0000.0000.000A.00.
  • N-, N- , .
  • A B flooding , .
  • C D flooding domain.
  • A D , . IS-IS ( , ).
. 1    OSI,   IS-IS

, IP, IS-IS . , , . , (SPF).


IS-IS

IS-IS . IS :

  • Hello-
  • (PSNP CSNP)
  • (Link State Packet - LSP)

LSP IS, , IS. LSP Type Length Vectors (TLV), . TLV :

  • 2 22:
  • 128, 135 235: IPv4
  • 236 237: IPv6

, , IS-IS 6- ( 8 , , , , ). , , , 24 - 32- , .

LSP, IS, IPv4 IPv6, , , MPLS , MTU. IS-IS LSP . . , , LSP. IS-IS , .


IS-IS , ES-IS, IS-IS IP, , IP, . . , IS-IS - , , .

IS-IS . 2 .

2:

  1. IS A B. , , . (hold time) B A, (MTU) . . MTU .
  2. IS B A. , , A. A B. MTU .
  3. A B, A B .
  4. A B , B A .
  5. B , (B LSP, ). Complete Sequence Number Packet (CSNP).
  6. A , , B. (LSP), , B Partial Sequence Number Packet (PSNP).
  7. B PSNP, Send Route Message (SRM) (LSP), A.
  8. SRM. , A B.
. , RFC5303, , , 2005 .
. 2 IS-IS

SRM , ?


.

SPF ( SPF) IS flooding domain . . IS-IS , ? point-to-point . , flooding domain (, Ethernet).

IS-IS LSP, , . 3 .

. 3   IS-IS LSP

3:

  • (packet length) . , 15 , 15 . 2 , 65 536 - , MTU .
  • (remaining lifetime) , LSP . , LSP, , , , , . , , , , IS , IS. , . 65 536 - - 1092 , 18 . LSP 18 .
  • LSP ID LSP. , , , ( ) LSP, , , LSP. , LSP, . LSP - IS. 8 .
  • (Sequence Number) LSP. , IS . , ( ) .
  • (Checksum) , , LSP, .

4.

. 4 IS-IS  (flooding)

4:

  1. 2001: db8: 3e8: 100 :: / 64. A , .
  2. A SRM B.
  3. - ( ) SRM.
  4. , B CSNP, , A.
  5. CSNP, A SRM B.
  6. B . , , . , , B C.

? IS-IS flooding:

  • IS .
  • - , IS (lifetime) 0 . , IS zero age SPF.
  • lifetime IS, zero age . IS, zero age, , ( ), . .

IS CNSP , , . , , .


IS-IS

IS-IS :

  • flooding domain ( ).
  • loop-free - SPF .
  • ( ).
  • .
  • (lifetime) .
  • MTU .
  • , , .

IS-IS - , .


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