NAME

routerSendRedirectOfflink - TBD

TARGET

  Router Only

SYNOPSIS

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

INITIALIZATION

Initialization was done by a previous test.

TEST PROCEDURE

routerSendRedirectOfflink verifies that that NUT send a redirect message if NUT know the better router's link-local address.

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


  ==== echo-request to H3 ===>
       TN throws an echo-request to NUT
       mac src=TN
       mac dst=NUT
       ip src=TN's global
       ip dst=H3's global


  <=== NS for R1 (if any) ====
       src=NUT's link-local
       dst=R1's link-local
       target=R1's link-local
       w/ SLLA


  ==== NA for R1 (if any) ===>
       src=R1's link-local
       dst=NUT's link-local
       target=R1's link-local
       R=1, S=1, O=1
       w/ TLLA


  <=== echo-request to H3 ====
       NUT forwards an echo-request to R1
       mac src=NUT
       mac dst=R1
       ip src=TN's global
       ip dst=H3's global


  <=== NS for TN (if any) ====
       src=NUT's link-local
       dst=solicited-node[TN's global]
       target=TN's global
       w/ SLLA


  ==== NA for TN (if any) ===>
       src=TN's global
       dst=NUT's link-local
       target=TN's global
       R=0, S=1, O=1
       w/ TLLA


  <=== Redirect ====
       src=NUT's link-local
       dst=TN's global
       target=R1's link-local
       icmp dst=H3's global
       w/ OR w/o TLLA
       w/ OR w/o Redirected header

JUDGMENT

  1. NUT must fowards an echo-request to the better router, R1:


  2. NUT must send a redirect message to TN:
     ip src=NUT's link-local
     ip dst=TN's global
     icmp target=R1's link-local
     icmp dst=H3's global

TERMINATION

N/A

NOTE

  NUT may send a redirect message that contains a redirected header option,
  but whose hop limit value is decreased from the original one.
  It does make sense. In such case, this test will judges "WARN" instead of
  "PASS" to notify the difference.

REFERENCE

RFC2461

8.2.  Router Specification


   A router SHOULD send a redirect message, subject to rate limiting,
   whenever it forwards a packet that is not explicitly addressed to
   itself (i.e. a packet that is not source routed through the router)
   in which:


      - the Source Address field of the packet identifies a neighbor,
        and


      - the router determines that a better first-hop node resides on
        the same link as the sending node for the Destination Address of
        the packet being forwarded, and


      - the Destination Address of the packet is not a multicast
        address, and


   The transmitted redirect packet contains, consistent with the message
   format given in Section 4.5:


      - In the Target Address field: the address to which subsequent
        packets for the destination SHOULD be sent.  If the target is a
        router, that router's link-local address MUST be used.  If the
        target is a host the target address field MUST be set to the
        same value as the Destination Address field.


      - In the Destination Address field: the destination address of the
        invoking IP packet.


      - In the options:


           o Target Link-Layer Address option: link-layer address of the
             target, if known.


           o Redirected Header: as much of the forwarded packet as can
             fit without the redirect packet exceeding 1280 octets in
             size.


   A router MUST limit the rate at which Redirect messages are sent, in
   order to limit the bandwidth and processing costs incurred by the
   Redirect messages when the source does not correctly respond to the
   Redirects, or the source chooses to ignore unauthenticated Redirect
   messages.  More details on the rate-limiting of ICMP error messages
   can be found in [ICMPv6].