So much detail! Thanks very much guys, I'm sure that all this excellent info will be valuable to others as well.<br>
<br>
Gratefully yours,<br>
H<br><br><div><span class="gmail_quote">On 10/5/06, <b class="gmail_sendername">Brian Candler</b> <<a href="mailto:B.Candler@pobox.com">B.Candler@pobox.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
On Thu, Oct 05, 2006 at 10:53:14AM +0200, raphael Jacquot wrote:<br>> Brian Candler wrote:<br>><br>> >However on ADSL, you have to add the 15% ATM cell tax. And you would be<br>> >wise<br>> >to add 20% headroom (
i.e. so your line is not more than 80% full)<br>><br>> ATM cell tax is actually 10% as there's 5 header bytes for each 53 bytes<br>> cell,<br><br>Only if all cells are filled. On average there will be half a cell empty at
<br>the end of each packet.<br><br>A common case is 1500-byte packets; these will take 32 cells, or 1696 bytes<br>total, giving a tax of 13%. Mix some smaller packets in with that and you<br>get a higher tax. So I tend to work on 15% as a rule of thumb.
<br><br>However it's worse for VoIP as has been pointed out. e.g. if you are sending<br>60 byte packets (20 IP, 8 UDP, 12 RTP, 20 G729) then they will take two<br>53-byte cells, so you pay 46 extra bytes to carry 60 bytes of IP; the tax is
<br>then 77%<br><br>(You will also have encapsulation, e.g. PPPoA, but that probably fits in the<br>wasted space without needing another cell)<br><br>Regards,<br><br>Brian.<br>_______________________________________________
<br>--Bandwidth and Colocation provided by <a href="http://Easynews.com">Easynews.com</a> --<br><br>asterisk-users mailing list<br>To UNSUBSCRIBE or update options visit:<br> <a href="http://lists.digium.com/mailman/listinfo/asterisk-users">
http://lists.digium.com/mailman/listinfo/asterisk-users</a><br></blockquote></div><br>