routerRecvRa - TBD


Router only


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


  Clear NC state for TN.


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


=================+============================= 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) | | | =================+=========+=======+===========




  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.



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.


  perldoc V6evalTool
  perldoc V6evalRemote