NAME

ncStateByNs4Probe - Verifying State Machine: NS vs. PROBE

TARGET

Host and Router

SYNOPSIS

  ncStateByNs4Probe.seq [-tooloption ...] -p ncStateByNs4Probe.def

INITIALIZATION

Set the state of neighbor cache entry to REACHABLE.
Cache either TN's LLA, or a bogus LLA

Cache a LLA of TN

  TN                 NUT
  ----------------------
  State: No neighbor cache entry (for TN)


  ==== echo-request ===>
        src=TN's link-local
        dst=NUT's link-local


  State: INCOMPLETE (for TN)


  <=== multicast NS ====
        src=NUT's link-local or global
        dst=solicited-node[TN's link-local]
        target=TN's link-local
        w/ SLLA
        timeout: RETRANS_TIMER * MAX_MULTICAST_SOLICIT


  ==== solicited NA ===>
        src=TN's link-local
        dst=NUT's link-local
        target=TN's link-local
        TLLA=TN's LLA


  State: REACHABLE (for TN)


  <=== echo-reply ====
        src=NUT's link-local
        dst=TN's link-local
        timeout: 2 sec


  Wait (REACHABLE_TIME * MAX_RANDOM_FACTOR)


  State: STALE (for TN)


  ==== echo-request ===>
        src=TN's link-local
        dst=NUT's link-local


  <=== echo-reply ====
        src=NUT's link-local
        dst=TN's link-local
        timeout: 2 sec


  State: DELAY (for TN)


  Wait (DELAY_FIRST_PROBE_TIME)


  State: PROBE (for TN)

Cache a bogus LLA

  TN                 NUT
  ----------------------
  State: No neighbor cache entry (for TN)


  ==== echo-request ===>
        src=TN's link-local
        dst=NUT's link-local


  State: INCOMPLETE (for TN)


  <=== multicast NS ====
        src=NUT's link-local or global
        dst=solicited-node[TN's link-local]
        target=TN's link-local
        w/ SLLA
        timeout: RETRANS_TIMER * MAX_MULTICAST_SOLICIT


  ==== solicited NA ===>
        src=TN's link-local
        dst=NUT's link-local
        target=TN's link-local
        TLLA=a bogus LLA


  State: REACHABLE (for TN)


  <=== echo-reply ====
        src=NUT's link-local
        dst=TN's link-local
        timeout: 2 sec


  Wait (REACHABLE_TIME * MAX_RANDOM_FACTOR)


  State: STALE (for TN)


  ==== echo-request ===>
        src=TN's link-local
        dst=NUT's link-local


  <=== echo-reply ====
        src=NUT's link-local
        dst=TN's link-local
        timeout: 2 sec


  State: DELAY (for TN)


  Wait (DELAY_FIRST_PROBE_TIME)


  State: PROBE (for TN)

TEST PROCEDURE

ncStateByNs4Probe verifies that state transition for a NUT in PROBE state when receiving an NS.

  TN                 NUT
  ----------------------


  State: PROBE (for TN)


  ==== NS ===>
        src=TN's link-local
        dst=NUT's link-local or solicited-node[NUT's link-local]
        w/o or w/ SLLA


  Judgment: Examining NUT's neighbor cache state

JUDGMENT

  ===============================+==========+=========+=================
  NS                             |New State |LLA       Comments
  ---------+-----------+---------+          |
  Source IP|Destination|SLLA     |          |
           |IP         |         |          |
  =========+===========+=========+==========+=========+=================
  TN's link Unicast     same      PROBE      unchanged
  ---------+-----------+---------+----------+---------+-----------------
  TN's link Multicast   same      PROBE      unchanged
  =========+===========+=========+==========+=========+=================
  TN's link Unicast     different STALE      changed
  ---------+-----------+---------+----------+---------+-----------------
  TN's link Multicast   different STALE      changed
  =========+===========+=========+==========+=========+=================

TERMINATION

N/A

NOTE

  The test does not invoke any remote command.

REFERENCE

RFC2461

7.2.3.  Receipt of Neighbor Solicitations

   A valid Neighbor Solicitation that does not meet any the following
   requirements MUST be silently discarded:

    - The Target Address is a "valid" unicast or anycast address
      assigned to the receiving interface [ADDRCONF],

    - The Target Address is a unicast address for which the node is
      offering proxy service, or

    - The Target Address is a "tentative" address on which Duplicate
      Address Detection is being performed [ADDRCONF].

   If the Target Address is tentative, the Neighbor Solicitation should
   be processed as described in [ADDRCONF].  Otherwise, the following
   description applies.  If the Source Address is not the unspecified
   address and, on link layers that have addresses, the solicitation
   includes a Source Link-Layer Address option, then the recipient
   SHOULD create or update the Neighbor Cache entry for the IP Source
   Address of the solicitation.  If an entry does not already exist, the
   node SHOULD create a new one and set its reachability state to STALE
   as specified in Section 7.3.3.  If an entry already exists, and the
   cached link-layer address differs from the one in the received Source
   Link-Layer option, the cached address should be replaced by the
   received address and the entry's reachability state MUST be set to
   STALE.