# NAME

            hoplimit.seq - Verify that decrease hoplimt when the
            encapulating packet is forwarded

# TARGET

            Router

# SYNOPSIS

            hoplimt.seq [-tooloption ...] -p
            hoplimit.def

# INITIALIZATION

    	Before this test starts, run initialize.seq.

# TEST PROCEDURE

            This test verifies that NUT decrease hoplimit when forward through tnnnel.

            Network Topology

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

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

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

            - encapsulation, and forwarding a packet
            1.
            ===================>
            ICMPv6 Echo Request
                    IPv6 Header
                            src address : TN LINK0  IPv6 global address
                            dst address : Off-link IPv6 global address
                            hoplimit : 64

            2.
            In NUT, received ICMPv6 Echo Request packet is encapsulated,
            and forward IPv4 packet

            3.
            <<JUDGMENT>>
                                       <===================
            IPv4 packet encapsulating IPv6 packet
                    Outer Header (IPv4)
                            src address : NUT Link1 IPv4 address
                            dst address : Off-link IPv4 address
                    Inner Header (IPv6)
                            src address : TN LINK0 IPv6 global address
                            dst address : Off-link IPv6 global address
                            hoplimit : 63 (for ISDN router, 62)

            - decapsulation, and forwarding a packet
            4.
                                    ===================>
            IPv4 packet encapsulating IPv6 packet
                    Outer Header (IPv4)
                            src address : Off-link IPv4 address
                            dst address : NUT Link1 IPv4 address
                    Inner Header (IPv6)
                            src address : Off-link IPv6 global address
                            dst address : TN LINK0 IPv6 global address
                            hoplimit : 64

            5.
            In NUT, received IPv4 packet is decapsulated, and forward
            ICMPv6 Echo Request packet.
            6.
            << JUDGMENT >>

            <===================
            ICMPv6 Echo Reply
                    IPv6 Header
                            src address : Off-link IPv6 global address
                            dst address : TN LINK0  IPv6 global address
                            hoplimit : 63 (for ISDN router, 62)

# JUDGMENT

            << PASS >>
                    NUT decreased hoplimit

            << FAIL >>
                    NUT did not decrease hoplimit

# SEE ALSO

              perldoc V6evalTool