RFC 2642 (rfc2642) - Page 2 of 95


Cabletron's VLS Protocol Specification



Alternative Format: Original Text Document



RFC 2642         Cabletron's VLS Protocol Specification      August 1999


       2.5 Protocol Data Structures............................ 12
       2.6 Basic Implementation Requirements................... 12
       2.7 Organization of the Remainder of This Document...... 13
    3. Interface Data Structure................................ 14
       3.1 Interface States.................................... 16
       3.2 Events Causing Interface State Changes.............. 18
       3.3 Interface State Machine............................. 21
    4. Neighbor Data Structure................................. 23
       4.1 Neighbor States..................................... 25
       4.2 Events Causing Neighbor State Changes............... 27
       4.3 Neighbor State Machine.............................. 29
    5. Area Data Structure..................................... 33
       5.1 Adding and Deleting Link State Advertisements....... 34
       5.2 Accessing Link State Advertisements................. 35
       5.3 Best Path Lookup.................................... 35
    6. Discovery Process....................................... 35
       6.1 Neighbor Discovery.................................. 36
       6.2 Bidirectional Communication......................... 37
       6.3 Designated Switch................................... 38
           6.3.1 Selecting the Designated Switch............... 39
       6.4 Adjacencies......................................... 41
    7. Synchronizing the Databases............................. 42
       7.1 Link State Advertisements........................... 43
           7.1.1 Determining Which
                 Link State Advertisement Is Newer............. 44
       7.2 Database Exchange Process........................... 44
           7.2.1 Database Description Packets.................. 44
           7.2.2 Negotiating the Master/Slave Relationship..... 45
           7.2.3 Exchanging Database Description Packets....... 46
       7.3 Updating the Database............................... 48
       7.4 An Example.......................................... 49
    8. Maintaining the Databases............................... 51
       8.1 Originating Link State Advertisements............... 52
           8.1.1 Switch Link Advertisements.................... 52
           8.1.2 Network Link Advertisements................... 55
       8.2 Distributing Link State Advertisements.............. 56
           8.2.1 Overview...................................... 57
           8.2.2 Processing an
                 Incoming Link State Update Packet............. 58
           8.2.3 Forwarding Link State Advertisements.......... 60
           8.2.4 Installing Link
                 State Advertisements in the Database.......... 62
           8.2.5 Retransmitting Link State Advertisements...... 63
           8.2.6 Acknowledging Link State Advertisements....... 64
       8.3 Aging the Link State Database....................... 66
           8.3.1 Premature Aging of Advertisements............. 66
    9. Calculating the Best Paths.............................. 67
   10. Protocol Packets........................................ 67



Kane                         Informational