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

        - 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

JUDGMENT

        << PASS >>
                NUT decreased hoplimit 
                

        << FAIL >>      
                NUT did not decrease hoplimit 

SEE ALSO

          perldoc V6evalTool