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Spirent KB Article
Doc ID: FAQ10834
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Spirent TestCenter: How do I configure a static value for the IP identification ID field of the IPv4 header?
Environment/Versions
Spirent TestCenter
Answer
The IP Identifier field increments for every packet; ID field in IP header is automatically incremented by hardware and associated with the checksum header.
Below are two methods to meet the requirement of keeping the IP ID:
Method 1:
Configure a VFD on the Identifier field, initial value 0 (for constant IP ID = 0), step 1, count 65536 (see screenshot). This is limited to a total of 65536.
To increase the number of packets:
Configure StreamBlock Scheduler to Rate Based
Duration Mode to Burst
Configure the load to 1/10 of the default 10 % = 1.0 %
Duplicate the StreamBlocks 9 times for a total of 10 StreamBlocks
Increase the burst size 65535 X 10 that will increase the number to 655350
If more required, instead increase the number of packets:
Configure StreamBlock Scheduler to Rate Based
Duration Mode to Burst
Configure the load to 1/1000 of the default 10 % = 0.01 %
Duplicate the StreamBlocks 999 times for a total of 1000 StreamBlocks
Increase the burst size 65535 X 1000 that will increase the number to 65535000.
NOTE: there is a known limitation for the DX-10G-S32 it works once then fails (ID increments). By taking the port offline and online, it will work once again.
Method 2:
As a second solution, as there is a difference between StreamBlocks created by Spirent TestCenter which are hardware generated and custom StreamBlocks that regard the StreamBlock as data, you can create the StreamBlock you require and transmit a burst that size to transmit and capture using Wireshark.
Create a custom StreamBlock from each in the following manner (instructions how to copy Wireshark packet to TestCenter):
Open trace file: right click on top on the packet, scroll down to Copy ->Bytes (Hex Stream)
Open Spirent TestCenter
Reserve port
Traffic Generator -> Add Raw Stream Block
General – Frame Size Auto
Frame – Create New Frame
Allow Invalid Packets
Data Link Layer - None
Upper Layer Protocol – None
Category – Custom
OK
Custom – Byte Pattern (hex) Paste
General – Signature (perhaps deselect)
OK
Apply
TX and capture to verify
Version
9.0
Publish Date
2016-08-18
Categories
Product : L2-3,Spirent TestCenter,IP,PGA
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