checkPMTUincrease - Verify increasing Path MTU
Host
checkPMTUincrease.seq [-tooloption ...] -p checkPMTUincrease.def
This test evaluate the behavior of NUT when 5 min and 10 min has past
since last Packet Too Big Message.
In this test, NUT is a host and TN plays a Roll of Router and
other host.
Physical Network configuration
--------+---------------+--------------
| |
NUT TN
Logical Network Configuration
NUT
|
----------------+-------+---------
|
Router
|
--------+-------+-----------------
|
HOST
NUT < --- Router --- > HOST
In this test, NUT receives Packet Too Big Message and
wait for a while.
- Decrease PMTU for HOST from 1500 to 1280
- Confirm PMTU for HOST is changed to 1280
- Wait for 295 sec
- Confirm PMTU for HOST is still 1280
- Wait for 305 sec
- Confirm PMTU for HOST is reset to 1500
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
Wait (5 sec.)
Ignoring DAD packets for global address.
"checkPMTUincrease" verifies NUT's resetting of Path MTU.
- NUT must not attempt to detect an increase less than 5
minutes after a Too Big Mesg.
TN NUT
| |
--+-------------------+----
1.
TN send Echo Request.
TN === echo request(1500) ===> NUT
2.
NUT send Echo Reply.
TN <=== echo reply(1500) === NUT
3.
TN send ICMPv6 Too Big Mesg include MTU (1280).
TN === ICMPv6 Too Big Mesg(1280) ===> NUT
4.
TN send Echo Request.
TN === echo request(1500) ===> NUT
5.
NUT send Echo Reply
<< JUDGMENT 1 >>
TN <=== echo reply(1280 1/2) === NUT
TN <=== echo reply( 276 2/2) === NUT
6.
TN sleep 295 seconds in perl script.
7.
TN send Echo Request.
TN === echo request(1500) ===> NUT
8.
NUT send Echo Reply
<< JUDGMENT 2 >>
TN <=== echo reply(1280 1/2) === NUT
TN <=== echo reply( 276 2/2) === NUT
9.
TN sleep 305 seconds in perl script.
10.
TN send Echo Request.
TN === echo request(1500) ===> NUT
11.
NUT send Echo Reply
<< JUDGMENT 3 >>
TN <=== echo reply(1500) === NUT
<< JUDGMENT 1 -PASS- >>
NUT sends fragmented Echo Reply.
NUT accept ICMP Packet Too Big Message and register the
MTU according to the ICMP message.
<< JUDGMENT 2 -PASS- >>
NUT sends fragmented Echo Reply.
NUT does not reset MTU value in 5 min.
<< JUDGMENT 2 -PASS- >>
NUT sends fragmented Echo Reply.
NUT reset MTU value after 10 min.
Note: The value 10 min is just recommended value,
so implementation can use other value to reset the PMTU.
perldoc V6evalTool
perldoc V6evalRemote