NAME

routerRecvRa - TBD

TARGET

Router only

SYNOPSIS

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

INITIALIZATION

  Clear NC state for TN.

TEST PROCEDURE

routerRecvRa verifies that state transition for a NUT in NONCE state when receiving a RA.

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


  State: NONCE (for TN)


  ==== RA ===>


  Judgment: Examining NUT's neighbor cache state

JUDGMENT


  =================+=============================
  RA               | Neighbor Cache                                
                   +---------+-------+-----------
                   | Current | New   | LLA       
  =================+=========+=======+===========
  w/o TLLA         | NONCE   | NONCE | unchanged 
  -----------------+---------+-------+-----------
  w/  TLLA         | NONCE   | NONCE | unchanged
  -----------------+---------+-------+-----------
  w/ TLLA          | NONCE   | NONCE | unchanged
  src!=link-local  |         |       |
  (INVALID)        |         |       |
  -----------------+---------+-------+-----------
  w/ TLLA          | NONCE   | NONCE | unchanged
  hoplimit!=255    |         |       |
  (INVALID)        |         |       |
  -----------------+---------+-------+-----------
  w/ TLLA          | NONCE   | NONCE | unchanged
  invalid checksum |         |       |
  (INVALID)        |         |       |
  -----------------+---------+-------+-----------
  w/ TLLA          | NONCE   | NONCE | unchanged
  icmp code!=0     |         |       |
  (INVALID)        |         |       |
  =================+=========+=======+===========

TERMINATION

N/A

NOTE

  RFC2461 does not describes an NCE state transition in a router when receiving RAs.
  However, it seems to be better that any RA should not affect the state.

REFERENCE

RFC2461

6.2.7.  Router Advertisement Consistency


   Routers SHOULD inspect valid Router Advertisements sent by other
   routers and verify that the routers are advertising consistent
   information on a link.  Detected inconsistencies indicate that one or
   more routers might be misconfigured and SHOULD be logged to system or
   network management.  The minimum set of information to check
   includes:


    - Cur Hop Limit values (except for the unspecified value of zero).


    - Values of the M or O flags.


    - Reachable Time values (except for the unspecified value of zero).


    - Retrans Timer values (except for the unspecified value of zero).


    - Values in the MTU options.


    - Preferred and Valid Lifetimes for the same prefix.  If
      AdvPreferredLifetime and/or AdvValidLifetime decrement in real
      time as specified in section 6.2.7 then the comparison of the
      lifetimes can not compare the content of the fields in the Router
      Advertisement but must instead compare the time at which the
      prefix will become deprecated and invalidated, respectively.  Due
      to link propagation delays and potentially poorly synchronized
      clocks between the routers such comparison SHOULD allow some time
      skew.


   Note that it is not an error for different routers to advertise
   different sets of prefixes.  Also, some routers might leave some
   fields as unspecified, i.e., with the value zero, while other routers
   specify values.  The logging of errors SHOULD be restricted to
   conflicting information that causes hosts to switch from one value to
   another with each received advertisement.


   Any other action on reception of Router Advertisement messages by a
   router is beyond the scope of this document.