# NAME

            rfc2765_4.1_trafficclass.seq - Verify IPv6 <-> IPv4 header
            translation in accordance with RFC2765 [SIIT]

# TARGET

            Router

# SYNOPSIS

            rfc2765_4.1_trafficclass.seq [-tooloption ...]
            -p rfc2765_4.1_trafficclass.def

# INITIALIZATION

    	Before this test starts, run initialize.seq.

# TEST PROCEDURE

            This test verifies that NUT translates IPv6 Traffic Class
            to IPv4 TOS.

            Network Topology

            Link0
            --------------------------
                |               |
               TN              NUT
                |               |
            --------------------------
            Link1

            TN -- (Link0) -- NUT        NUT -- (Link1) -- TN

            ---------------------      ------------------------

            1.[1-4]
            ===================>
            ICMPv6 Echo Request
                    IPv6 Header
                            src address : TN LINK1 IPv4 embedded IPv6 address
                            dst address : TN LINK0 IPv4 embedded IPv6 address
                            Traffic Class = 0,15,63,255 (4 tests)
                    ICMPv6 echo request

            1.[1-4]
            <<JUDGMENT>>
                                       ===================>
            ICMPv4 Echo request
                    IPv4 Header
                            src address : TN LINK1 IPv4 address
                            dst address : TN LINK0 IPv4 address
                            Don't Fragment = 1
                            More fragments = 0
                            Offset = 0
                            TOS = 0,15,63,255 or 0,0,0,0
                    ICMPv4 echo request

# JUDGMENT

            << PASS >>
                    TN (Link1) receive four ICMPv4 echo requests,
                    with TOS field same as IPv6 Traffic class.

            << WARN >>
                    TN (Link1) receive four ICMPv4 echo requests,
                    with TOS = 0.

            << FAIL >>
                    TN (Link0) does not receive four ICMPv4 echo requests,
                    with TOS field = 0 or same as IPv6 Traffic class.

# NOTE

# REFERENCE

RFC2765

4.1. Translating IPv6 Headers into IPv4 Headers

       If there is no IPv6 Fragment header the IPv4 header fields are set as
       follows:

             Version:
                     4

             Internet Header Length:
                     5 (no IPv4 options)

             Type of Service and Precedence:
                     By default, copied from the IPv6 Traffic Class (all 8
                     bits).  According to [DIFFSERV] the semantics of the
                     bits are identical in IPv4 and IPv6.  However, in
                     some IPv4 environments these bits might be used with
                     the old semantics of "Type Of Service and
                     Precedence".  An implementation of a translator
                     SHOULD provide the ability to ignore the IPv6 traffic
                     class and always set the IPv4 "TOS" to zero.

# SEE ALSO

            perldoc V6evalTool