checkIncreasePMTU - Checking For Increase in PMTU
Host and Router
checkIncreasePMTU.seq [-tooloption ...] -pkt checkIncreasePMTU.def
-tooloption : v6eval tool option
Common Test Setup 1.1
Verify that a node waits the proper amount of time to check for PMTU increases.
TN2 TR1 NUT
| | |
|-------------------------------------------->|
| 1.Echo Request | |
| (1440 octets) | |
| | |
|<--------------------------------------------|
| 2.Echo Reply | |
| (1440 octets) | |
| | |
| +--------------------->|
| | 3.Packet Too Big |
| | (MTU 1280) |
| | |
|-------------------------------------------->| ---
| 4.Echo Request | | |
| (1440 octets) | | |
| | | |
|<--------------------------------------------| |
| 5.Fragment Echo Reply| | |
| (1st + 2nd = 1440) | | |
| | | | repeat every 30 seconds for 5 minutes
| [30 sec.] | | |
| | | |
|-------------------------------------------->| |
| Echo Request | | |
| (1440 octets) | | |
| | | |
|<--------------------------------------------| ---
| Fragment Echo Reply| |
| (1st + 2nd = 1440) | |
| | |
| [30 sec.] | |
| | |
v v v
1. Send Echo Request 2. Receive Echo Reply <<Check 1>> 3. Send Packet Too Big message 4. Send Echo Request 5. Receive fragmented Echo Reply <<Check 2>> 6. go to step 4, repeat every 30 seconds for 5 minutes
Echo Request Data is:
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 1400
NextHeader = 58 (ICMPv6)
SourceAddress = TN2's Global Address
DestinationAddress = NUT's Global Address
ICMP Echo Request
Type = 128 (Echo Request)
Code = 0
Checksum = (auto)
Identifier = 0xffff
SequenceNumber = 1
PayloadData = (1392 octets)
Packet Too Big message is:
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 1280
NextHeader = 58 (ICMPv6)
SourceAddress = TR1's Global Address
DestinationAddress = NUT's Global Address
ICMP Echo Request
Type = 2 (Packet Too Big)
Code = 0xff
Checksum = (auto)
MTU = 1304
PayloadData = (1232 octets)
PASS: <<Check 1>> Echo Reply Received or Fragment Echo Reply Received
<<Check 2>> Fragment Echo Reply Received. 1st and 2nd fragment no larger than 1304 octets.
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 1400
NextHeader = 58 (ICMPv6)
SourceAddress = NUT's Global Address
Destination Address = TN2's Global Address
ICMP Echo Reply
Type = 129 (Echo Reply)
Code = 0
Checksum = (auto)
Identifier = 0xffff (same as Echo Request)
SequenceNumber = 1 (same as Echo Request)
PayloadData = (1392 octets) (same as Echo Request)
Common Test Cleanup
RFC 8201 - Path MTU Discovery for IPv6
perldoc V6evalTool