For the record, as an author of XEP-0301, I specifically designed XEP-0301 to have flexibility for a wide variety of situations. The official word (by the author, myself) or XEP-0301, is that there is no specific set average for XEP-0301. For that reason, Gunnar's average is for a very specific situation, and is not necessarily representative of an average appropriate for a telecom, which may already have their infrastructure that warrants different variables than Gunnar's average situation.
Sincerely, Mark Rejhon On Tue, May 15, 2012 at 11:17 PM, Gunnar Hellström < [email protected]> wrote: > We never answered the original question. "What is the average packet size > of XEP-0301?" > > Here it is: around 370 bytes per packet. > > Motivation: > > Still assuming that we send every 700 ms and the typing trate is 5 > characters per second. > > The contribution from the characters will be 5*0.7*20 = 70 bytes per > packet. > > With the general overhead in a packet and the XEP-0301 specific elements, > it will be around 370 bytes per packet. > > The variations caused by variations in the general packet overhead from > address length, compression or not, inclusion of various options etc, make > it not feasible to predict it more closely. > > Is this sufficient for your use? > > > Gunnar > > ___________________________________________________ > Gunnar Hellström > [email protected]+46708204288 > > > Gunnar Hellström skrev 2012-05-15 22:19: > > In order to get an approximate value, we could check what we get with > recommended values for the optional items. > > 1. I think it is quite common that the overhead in XMPP gets around 300 > bytes per packet. (It might be 200 in some conditions.) > > 2. The recommended rate of packets is one every 700 ms as long as new text > is produced. Thus 1.4 packets per second. = 420 bytes per second overhead. > > 3. The text plus keypress interval information is often 20 bytes per > character. ( see XEP-0301 section7.9 ) 5 characters per second is then 100 > bytes per second. > > 4. The sum with this example is 520 bytes per second or 4.2 kbit/s, in > 1.4 packets per second. > > 5. Since the values for overhead were very coarse, we should round off to > about 500 bytes/s and 4 kbit/s in 1.5 packets/s. > > 6. If you select options differently, you will have different results. > > Gunnar > > ___________________________________________________ > Gunnar Hellström > [email protected]+46708204288 > > > Mark Rejhon skrev 2012-05-15 20:24: > > Hello Darren, > > The bitrate can pretty much range from less than 100 bytes a second > (when XEP-0138 compression is used) to several kilobits per second (with > Natural Typing at 300ms transmission intervals). Even at the worst case > scenario, several kilobits per second is less bitrate than a cell phone > call. Also, zero bandwidth is used when typing is not occuring. Also, > there is a huge amount of variables that determine the bandwidth, some of > which can be controlled by the software implementation: > > The biggest impact on bandwidth of XEP-0301 are as follows: > > (1) Is key press intervals being preserved? (Natural Typing) (uses more > bandwidth) > Section 6.1.1 at > http://xmpp.org/extensions/xep-0301.html#text_presentation > Animation: http://www.realjabber.org/real_time_text_demo.html > > (2) What transmission interval is being used? (shorter uses more > bandwidth) > Section 4.4 at > http://xmpp.org/extensions/xep-0301.html#transmission_interval > > (3) Is XEP-0138 stream compression being used? (uses less bandwidth) > See http://xmpp.org/extensions/xep-0138.html > > (4) Are you using an optimized XMPP server that keeps headers compact? > (i.e. eliminates a lot of XMPP payloads such as noarchive indicators or <x> > tags). This overhead is added by Google Talk's servers and adds an > additional >100 bytes per <message> packet. > > Also, to help get started if you wish, are welcome to take my Apache 2.0 > source code (commercial use allowed) to help make it easier to implement > XEP-0301 in your network: > C# -- > http://code.google.com/p/realjabber/source/browse/trunk/CSharp/RealTimeText.cs > Java -- > > http://code.google.com/p/realjabber/source/browse/trunk/Java/src/RealTimeText.java > > My XEP-0301 standard is designed precisely for the purposes you're > interested in! Once you can answer the variables #1,2,3,4, I can give you > more accurate bandwidth estimates to your questions. > > Cheers, > Mark Rejhon, deafie & computer programmer > Author of XEP-0301 > > > On Mon, May 14, 2012 at 6:25 AM, Darren Sturman < > [email protected]> wrote: > >> Hi Mark >> >> >> >> I am proposing the use of XEP-0301 for Web and Smart Phone apps for a >> deaf telephony system in the UK. >> >> >> >> Could you give me an estimate of the bandwidth requirements for the >> following: >> >> · Connected user who is idle >> >> o I am assuming “XEP-0199: XMPP Ping” which from a forum I see is >> approx. 22 bytes/second – is this correct? >> >> · Connected user conversation >> >> o What is the average packet size assuming one packet is transmitted >> per second? >> >> o Assuming an average user types at 60 words per minute >> >> § This would equate to 1 word per second which is classified as an >> average of 5 characters >> >> § What is the XMPP packet size minus the actual typed text? I have seen >> on one forum that is approx. 200 bytes >> >> · So 200 bytes plus 5 bytes for 5 typed characters? >> >> >> >> >> >> Kind Regards >> >> >> >> *Darren Sturman BSc (Hons) IT & Comp; MSc Soft Dev* >> >> *Senior Software Engineer* >> >> >> >> Teligent Limited >> >> Teligent House >> >> 2 Kings Hill Avenue >> >> Kings Hill, West Malling >> >> Kent ME19 4AQ >> >> England, UK >> >> >> >> Telephone: +44 (0) 1732 879 694<%2B44%20%280%29%201732%20879%20694> >> >> Mobile: +44 (0) 7968 130 >> 668<%2B44%20%280%29%207968%20130%20668> >> >> Facsmile: +44 (0) 1732 879 >> 601<%2B44%20%280%29%201732%20879%20601> >> >> Email: [email protected] >> >> Skype: darren.sturman.teligent >> >> Website: www.teligent.co.uk >> >> >> >> [image: Description: cid:[email protected]] >> >> >> >> Disclaimer: >> >> The information in this email is confidential. The contents may not be >> disclosed or used by anyone other than the addressee. If you are not the >> intended recipient, please notify the sender immediately at the above >> address. The sender cannot accept any responsibility for the accuracy or >> completeness of this message as it has been transmitted over a public >> network. If you suspect that the message may have been intercepted or >> amended, please contact the sender. >> >> >> >> Teligent Ltd is registered in England and Wales, registration number >> 2893478, registered office Lion House, Red Lion Street, London WC1R 4GB. >> VAT registration GB639938577 >> >> >> > >
binFkkqxdTEVT.bin
Description: Binary data
