[Ndn-interest] How to calculate max data bytes per packet?

Junxiao Shi shijunxiao at email.arizona.edu
Mon Aug 3 16:27:28 PDT 2015


Hi Qihan

There’s no general algorithm to compute the limit of payload size, because Signature is generated after Content is prepared, and theoretically its length can depend on the Content (although all defined signing algorithms don’t do that).

An application could detect the payload size by feedback loop: try different Content lengths, use a binary search to find out what’s the maximum size.
I haven’t seen any application doing this, because repeatedly signing is very slow.
I’ve seen “half of 8800”; I’ve also seen “8000 octets”.

Yours, Junxiao


From: ndn ndn
Sent: Monday, August 3, 2015 00:44
To: Junxiao Shi
Cc: ndn-interest at lists.cs.ucla.edu;ndn-lib at lists.cs.ucla.edu
Subject: Re: [Ndn-interest] How to calculate max data bytes per packet?


Limit the content payload in half of practical limit can not make best efficient in transmission.Why not to set a function  to get the max content payload? As a application programmer, We should consider data segment,Why NDN protocol to consider it , just like IP?


2015-08-03 10:34 GMT+08:00 Junxiao Shi <shijunxiao at email.arizona.edu>:

face.getMaxNdnPacketSize() gives the practical limit of NDN packet length.
For a Data packet, this length not only includes the Content payload, but also includes the Name, MetaInfo, and Signature.
There’s no general algorithm to compute the limit of payload size, because Signature is generated after Content is prepared, and theoretically its length can depend on the Content (although all defined signing algorithms don’t do that).
In most cases, it’s safe to limit your Content payload to be half of that practical limit. 
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