mmm ..
I have tested on mobile networks in Netherlands.It has many failures by
provider T-mobile. Because quatity of GRPS or 3G are not very good. I
have agreed with Gunnar that it's not only specific sitaution. it's now
known isusse that capaction of mobile system is not good.
Edward Tie
On 2012-05-16 06:10, Mark Rejhon wrote:
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
<gunnar.hellst...@omnitor.se <mailto:gunnar.hellst...@omnitor.se>> 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
Omnitor
gunnar.hellst...@omnitor.se <mailto:gunnar.hellst...@omnitor.se>
+46708204288 <tel:%2B46708204288>
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
Omnitor
gunnar.hellst...@omnitor.se <mailto:gunnar.hellst...@omnitor.se>
+46708204288 <tel:%2B46708204288>
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
<darren.stur...@teligent.co.uk
<mailto:darren.stur...@teligent.co.uk>> 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
oI am assuming “XEP-0199: XMPP Ping” which from a forum I
see is approx. 22 bytes/second – is this correct?
·Connected user conversation
oWhat is the average packet size assuming one packet is
transmitted per second?
oAssuming 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
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