hoplimit.seq - Verify that decrease hoplimt when the
encapulating packet is forwarded
Router
hoplimt.seq [-tooloption ...] -p
hoplimit.def
Before this test starts, run initialize.seq.
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)
<< PASS >>
NUT decreased hoplimit
<< FAIL >>
NUT did not decrease hoplimit
perldoc V6evalTool