Packet size

[gb]

Hello,

I have a few questions on packets.
1. I don't see a parameter in AX 3. Is there a default that Axapta has, it is using network default? What is the packet size?

2. In 4.0 there is a section in Help on Minimum packet size to compress (in KB)
http://msdn2.microsoft.com/en-US/library/aa569624.aspx
the defualt in AX 4 is '1'. But the question is what is the optimum size for best performance? How to evaluate it? Did anybody see any white papers from MS team?

Thank you for any comments and suggestions.
gb.

[gl00mie]

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Сообщение от gb

I don't see a parameter in AX 3. Is there a default that Axapta has, it is using network default? What is the packet size?

The topic has been discussed recently. Briefly, the client-server communication in AX3 is carried by TCP/IP and AX3 cannot control TCP max segment size. That value is usually 1460 bytes which gives a packet size of 1500 bytes (1460 + at least 20 bytes of TCP header + 20 bytes of IP header). In case this value is increased (not by means of AX3 ) you can run into situations where TCP packets become fragmented on the IP level because of limitations of maximum transmission unit (MTU) of an underlying network ...and that all leads us far beyond the subjects usually discussed on this forum

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Сообщение от gb

In 4.0 there is a section in Help on Minimum packet size to compress (in KB) http://msdn2.microsoft.com/en-US/library/aa569624.aspx the default in AX 4 is '1'. But the question is what is the optimum size for best performance?

By the way the help topic mentioned doesn't clarify what is assumed by a "packet" and what kind of compression is applied (i.e. on what layer the compression is applied). In DAX4 the AOCP traffic is encapsulated into RPC (MSRPC Payload BLOB on the screenshot) that uses authentication and packet integrity. It makes more difficult to fit into TCP max segment size and makes any data compression less efficient.
TCP maximum packet size parameter must balance two competing performance issues: overhead management and IP fragmentation. But if in case of DAX4 we measure packet sizes in KB (whatever is assumed by a packed in this context, say AOCP packets) then AOCP packet fragmentation is obviously inevitable as soon as it comes to the transmission via RPC. Then the only way to improve performance is to decrease the network traffic, so probably the least «Minimum packet size to compress» is the best.