# NAME

            setMTUwithRA - Verify changing MTU w/ received RA

# TARGET

            Host

# SYNOPSIS

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

# NETWORK CONFIGURATION

            This test evaluate the behavior of NUT when it receive the RA
            with MTU option.
            In this test, NUT is a host and TN plays a Roll of Router and
            other host.

            Phisical Network configuration

            --------+---------------+----------
                    |               |
                    NUT             TN

            Logical Network Configuration

                                    NUT
                                    |
            ----------------+-------+--------
                            |
                            Router-A
                            |
            ----------------+-------+--------
                                    |
                                    HOST

            In this test, NUT receives RA with MTU.

# INITIALIZATION

            The TN send a RA to assign global address prefix.

               TN          NUT
               |            |
            ---+------------+------

            ===multicast RA===>
            src=TN's link-local
            dst=LinkLocal-all-node
            M=0, O=0,
            Lifetime=3600, ReachableTime=60000, RetransTimer=1005
            Prefix:
               L=1, A=1,
               ValidLifetime=3600005, PreferredLifetime=3600005
               Prefix=3ffe:501:ffff:100::, PrefixLength=64
            option
               MTU=1400

              Wait (5 sec.)
                     Ignoring DAD packets for global address.

# TEST PROCEDURE

            "setMTUwithRA" verify NUT's behavior when it receives RA with MTU option.

               TN          NUT
               |            |
            ---+------------+------

            1. RA (MTU=1400)
            TN send RA with MTU=1400.
            TN === RA(MTU=1400) ===> NUT

            2. TN Sends Fragmented Echo Request
            TN send Echo Request.
            TN ==== echo request(1400) ===> NUT

            4. NUT Sends Fragmented Echo Reply
            NUT send Echo Reply.
            << JUDGMENT 1 >>
            TN <=== echo reply(1400) ====== NUT

            3. TN Sends Fragmented Echo Request
            TN send Echo Request.
            TN === echo request(1/2 of 1500 MTU=1400) ===> NUT
            TN === echo request(2/2 of 1500 MTU=1400) ===> NUT

            4. NUT Sends Fragmented Echo Reply
            NUT send Echo Reply
            << JUDGMENT 1 >>
            TN <=== echo reply(1/2 of 1500 MTU=1400) === NUT
            TN <=== echo reply(2/2 of 1500 MTU=1400) === NUT

# JUDGMENT

            << JUDGMENT 1 -PASS- >>
                    NUT sends Echo Reply

                    "PASS" means that NUT set valid MTU in received RA.
                    And fragmented packets are correct.
                    But if the NUT doesn't support PMTU Discovery, the NUT MUST NOT send echo reply greater than Minimum MTU.

            << JUDGMENT 2 -PASS- >>
                    NUT sends Echo Reply

                    "PASS" means that NUT sets valid MTU in received RA.
                    And fragmented packets are correct.
                    But if the NUT is LCNA, it may not be able to deal with packets greater than Minimum MTU, in this case NUT doesn't transmit echo reply. And also it could not fragment packets, in this case NUT doesn't transmit echo reply. Both cases are allowed in LCNA specification.

# SEE ALSO

            perldoc V6evalTool
            perldoc V6evalRemote