acceptTooBigMesg - Verify changeing Path MTU
received Too Big Message
Host
acceptTooBigMesg.seq [-tooloption ...] -p acceptTooBigMesg.def
This test is OFF-LINK Network Configuration test.
In this test, TN play a Roll of the Router.
Phisical Network configuration
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NUT TN
Logical Network Configuration
HOST A (globaladdress:A)
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----------------------------------
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Router
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NUT (globaladdress:B)
NUT < --- Router --- > HOST A
In this configuration, Packets are send and received.
for example,
In Logical
HOST A -- Echo Reply --> NUT
Actually, in physical
TN (as Router X) -- Echo Reply --> NUT
There are 2 patterns for initialize.
-- Test for host --
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.
-- Test for router --
TN attempts to execute remote command 'vRemote(route.rmt)'.
'route add -inet6 3ffe:501:ffff:109 TN'slink-local-address'
"acceptTooBigMesg" verify that changing Path MTU
when node receives Too Big Mesg.
Verifying accept valid Packet Too big message attempt to
test in 2 environment in which MTU is 1300 and 1400
TN NUT
---------------------------
1.
TN send Echo Request.
=== echo request ===>
2.
NUT send Echo Reply.
<=== echo reply ===
3.
TN send ICMPv6 Too Big Mesg include MTU (1400).
=== ICMPv6 Too Big Mesg ===>
4.1
TN send Echo Request which is fragmented.
orignal packet's size is 1399.
=== echo request 1st ===>
=== echo request 2nd ===>
4.2
NUT send Echo Reply
<< JUDGMENT 1 >>
<=== echo reply ===
5.1
TN send Echo Request which is fragmented.
orignal packet's size is 1400.
=== echo request 1st ===>
=== echo request 2nd ===>
5.2
NUT send Echo Reply
<< JUDGMENT 1 >>
<=== echo reply ===
6.1
TN send Echo Request which is fragmented.
orignal packet's size is 1401.
=== echo request 1st ===>
=== echo request 2nd ===>
6.2
NUT send Echo Reply which is fragmented.
<< JUDGMENT 1 >>
<=== echo reply 1st ===
<=== echo reply 2nd ===
and, this parts (1-6) test in MTU 1300
--------------------------------------------------------
verify that NUT ignore invalid MTU.
NUT must not increase its estimate of the Path MTU in
response to the contens of a Too Big Message
1.
TN send ICMPv6 Too Big Mesg include MTU (1450).
=== ICMPv6 Too Big Mesg ===>
<=== echo reply ===
2.1
TN send Echo Request which is fragmented.
orignal packet's size is 1299.
=== echo request 1st ===>
=== echo request 2nd ===>
2.2
NUT send Echo Reply
<< JUDGMENT 2 >>
<=== echo reply ===
3.1
TN send Echo Request which is fragmented.
orignal packet's size is 1300.
=== echo request 1st ===>
=== echo request 2nd ===>
3.2
NUT send Echo Reply
<< JUDGMENT 2 >>
<=== echo reply ===
4.1
TN send Echo Request which is fragmented.
orignal packet's size is 1301.
=== echo request 1st ===>
=== echo request 2nd ===>
4.2
NUT send Echo Reply which is fragmented.
<< JUDGMENT 2 >>
<=== echo reply 1st ===
<=== echo reply 2nd ===
--------------------------------------------------------
verify that NUT ignore invalid MTU.
NUT must not reduce its estimate of the Path MTU below
the IPv6 minimum link MTU.
1.
TN send Echo Request.
=== echo request ===>
2.
NUT send Echo Reply.
<=== echo reply ===
3.
TN send ICMPv6 Too Big Mesg include MTU (1200).
=== ICMPv6 Too Big Mesg ===>
4.1
TN send Echo Request which is fragmented.
orignal packet's size is 1280.
=== echo request 1st ===>
=== echo request 2nd ===>
4.2
NUT send Echo Reply
<< JUDGMENT 3 >>
<=== echo reply ===
<< JUDGMENT 1 -PASS- >>
NUT send 3 Echo Reply ( no fragment, no fragment, fragmented)
"PASS" means that NUT set valid MTU in response to accept
Packet too big message.
In first test, NUT's Path MTU of this path can be set 1300
In second test, NUT's Path MTU of this path can be set 1400.
<< JUDGMENT 2 -PASS- >>
NUT send 3 Echo Reply ( no fragment, no fragment, fragmented)
"PASS" means that NUT don't increase Path MTU in response to
accept invalid Packet Too Big Message
<< JUDGMENT 3 -PASS- >>
NUT send 1 Echo Reply ( no fragment)
"PASS" means that NUT don't set its Path MTU below IPv6 minimum
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perldoc V6evalRemote