Clarification regarding the ESP SN Encoding
Anil Maguluri <[email protected]> Wed, 16 Jun 2010 12:32:18 +0530
| Newsgroups | gmane.ietf.rohc |
|---|---|
| Message-ID | <903D13EA90218E43BA0881BC8B569C7D230903D6@BLRINMSMBX01.bglrodc.lntinfotech.com> |
--===============1929575011==
Content-Language: en-US
Content-Type: multipart/alternative;
boundary="_000_903D13EA90218E43BA0881BC8B569C7D230903D6BLRINMSMBX01bgl_"
--_000_903D13EA90218E43BA0881BC8B569C7D230903D6BLRINMSMBX01bgl_
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Hi All,
Currently I am working on ROHCv1 Profile-3 (ESP/IP).
Please let me know whether my understanding is right or not regarding the =
ESP SN Encoding.
As per RFC 3095, 4.5.1, " The parameter p is introduced so that the interp=
retation interval can be shifted with respect to v_ref.
Choosing a good value for p will yield a more efficient encoding for field=
s with certain characteristics. Below are some examples:
- P =3D -1 if the field value is expected to increase always
- p =3D 0 if the field value is constant or increase
- p =3D 2^(k-1) - 1, if the field value is expected to deviate sl=
ightly from a constant
- p =3D 2^(k-2) - 1, if the field value is expected to undergo sm=
all negative changes or larger positive changes "
Also RFC 3095, 5.7, " SN: The compressed RTP Sequence Number.
Compressed with W-LSB. The interpretation intervals, see section 4.5.1, ar=
e defined as follows:
p =3D 1 if bits(SN) <=3D 4
p =3D 2^(bits(SN)-5) - 1 if bits(SN) > 4 "
As per my understanding, we should use the below 'p' values at compressor=
[for SN Encoding]
- p=3D-1, if packets are received in-order
- p=3D2^(k-2)-1, if packets are received out-of-order
at decompressor
- p =3D 1 if bits(SN) <=3D 4
- p =3D 2^(bits(SN)-5) - 1 if bits(SN) > 4
Queries
1. Is my understanding is right?
2. What is the value of 'p' for Profile-3 at compressor and decompre=
ssor? Is it same as above?
Thanks for your support.
Regards,
Anil Kumar Maguluri
________________________________
This Email may contain confidential or privileged information for the inte=
nded recipient (s) If you are not the intended recipient, please do not us=
e or disseminate the information, notify the sender and delete it from you=
r system.
______________________________________________________________________
--_000_903D13EA90218E43BA0881BC8B569C7D230903D6BLRINMSMBX01bgl_
Content-Type: text/html; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
<html xmlns:v=3D"urn:schemas-microsoft-com:vml" xmlns:o=3D"urn:schemas-mic=
rosoft-com:office:office" xmlns:w=3D"urn:schemas-microsoft-com:office:word=
" xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" xmlns=3D"ht=
tp://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dus-ascii=
">
<meta name=3D"Generator" content=3D"Microsoft Word 12 (filtered medium)">
<style>
<!--
/* Font Definitions */
@font-face
=09{font-family:Wingdings;
=09panose-1:5 0 0 0 0 0 0 0 0 0;}
@font-face
=09{font-family:Wingdings;
=09panose-1:5 0 0 0 0 0 0 0 0 0;}
@font-face
=09{font-family:Calibri;
=09panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
=09{margin:0in;
=09margin-bottom:.0001pt;
=09font-size:11.0pt;
=09font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
=09{mso-style-priority:99;
=09color:blue;
=09text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
=09{mso-style-priority:99;
=09color:purple;
=09text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
=09{mso-style-priority:34;
=09margin-top:0in;
=09margin-right:0in;
=09margin-bottom:0in;
=09margin-left:.5in;
=09margin-bottom:.0001pt;
=09font-size:11.0pt;
=09font-family:"Calibri","sans-serif";}
span.EmailStyle17
=09{mso-style-type:personal-compose;
=09font-family:"Calibri","sans-serif";
=09color:windowtext;}
.MsoChpDefault
=09{mso-style-type:export-only;}
@page Section1
=09{size:8.5in 11.0in;
=09margin:1.0in 1.0in 1.0in 1.0in;}
div.Section1
=09{page:Section1;}
/* List Definitions */
@list l0
=09{mso-list-id:17241421;
=09mso-list-type:hybrid;
=09mso-list-template-ids:1587736046 -4665242 67698691 67698693 67698689 67=
698691 67698693 67698689 67698691 67698693;}
@list l0:level1
=09{mso-level-number-format:bullet;
=09mso-level-text:-;
=09mso-level-tab-stop:none;
=09mso-level-number-position:left;
=09text-indent:-.25in;
=09font-family:"Calibri","sans-serif";
=09mso-fareast-font-family:Calibri;
=09mso-bidi-font-family:"Times New Roman";}
@list l1
=09{mso-list-id:537473615;
=09mso-list-type:hybrid;
=09mso-list-template-ids:181568214 67698703 67698713 67698715 67698703 676=
98713 67698715 67698703 67698713 67698715;}
@list l1:level1
=09{mso-level-tab-stop:none;
=09mso-level-number-position:left;
=09margin-left:.25in;
=09text-indent:-.25in;}
@list l2
=09{mso-list-id:777481292;
=09mso-list-type:hybrid;
=09mso-list-template-ids:-2142334506 67698703 67698713 67698715 67698703 6=
7698713 67698715 67698703 67698713 67698715;}
@list l2:level1
=09{mso-level-tab-stop:none;
=09mso-level-number-position:left;
=09margin-left:.25in;
=09text-indent:-.25in;}
@list l2:level2
=09{mso-level-number-format:alpha-lower;
=09mso-level-tab-stop:none;
=09mso-level-number-position:left;
=09margin-left:.75in;
=09text-indent:-.25in;}
@list l2:level3
=09{mso-level-number-format:roman-lower;
=09mso-level-tab-stop:none;
=09mso-level-number-position:right;
=09margin-left:1.25in;
=09text-indent:-9.0pt;}
@list l3
=09{mso-list-id:1283342846;
=09mso-list-type:hybrid;
=09mso-list-template-ids:1349533138 67698703 67698713 67698715 67698703 67=
698713 67698715 67698703 67698713 67698715;}
@list l3:level1
=09{mso-level-tab-stop:none;
=09mso-level-number-position:left;
=09margin-left:.25in;
=09text-indent:-.25in;}
@list l3:level2
=09{mso-level-number-format:alpha-lower;
=09mso-level-tab-stop:none;
=09mso-level-number-position:left;
=09margin-left:.75in;
=09text-indent:-.25in;}
ol
=09{margin-bottom:0in;}
ul
=09{margin-bottom:0in;}
-->
</style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext=3D"edit">
<o:idmap v:ext=3D"edit" data=3D"1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=3D"EN-US" link=3D"blue" vlink=3D"purple">
<div class=3D"Section1">
<p class=3D"MsoNormal">Hi All,<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Currently I am working on ROHCv1 Profile-3 (ESP/IP)=
. <o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Please let me know whether my understanding is righ=
t or not regarding the ESP SN Encoding.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">As per RFC 3095, 4.5.1, <i>“ The parameter p =
is introduced so that the interpretation interval can be shifted with resp=
ect to v_ref.
<o:p></o:p></i></p>
<p class=3D"MsoNormal"><i>Choosing a good value for p will yield a more ef=
ficient encoding for fields with certain characteristics. Below are some e=
xamples:<o:p></o:p></i></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-.25in;mso-list:l0 leve=
l1 lfo2"><![if !supportLists]><span style=3D"mso-list:Ignore">-<span style=
=3D"font:7.0pt "Times New Roman""> =
</span></span><![endif]><i>P =3D -1 if the field value is expected to incr=
ease always<o:p></o:p></i></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-.25in;mso-list:l0 leve=
l1 lfo2"><![if !supportLists]><span style=3D"mso-list:Ignore">-<span style=
=3D"font:7.0pt "Times New Roman""> =
</span></span><![endif]><i>p =3D 0 if the field value is constant or incre=
ase<o:p></o:p></i></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-.25in;mso-list:l0 leve=
l1 lfo2"><![if !supportLists]><span style=3D"mso-list:Ignore">-<span style=
=3D"font:7.0pt "Times New Roman""> =
</span></span><![endif]><i>p =3D 2^(k-1) – 1, if the field value is =
expected to deviate slightly from a constant<o:p></o:p></i></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-.25in;mso-list:l0 leve=
l1 lfo2"><![if !supportLists]><span style=3D"mso-list:Ignore">-<span style=
=3D"font:7.0pt "Times New Roman""> =
</span></span><![endif]><i>p =3D 2^(k-2) – 1, if the field value is =
expected to undergo small negative changes or larger positive changes R=
20;<o:p></o:p></i></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Also RFC 3095, 5.7, <i>“ SN: The compressed R=
TP Sequence Number.<o:p></o:p></i></p>
<p class=3D"MsoNormal"><i>Compressed with W-LSB. The interpretation interv=
als, see section 4.5.1, are defined as follows:<o:p></o:p></i></p>
<p class=3D"MsoNormal"><i>p =3D 1 if bits(SN) <=3D 4<o:p></o:p></i></p>=
<p class=3D"MsoNormal"><i>p =3D 2^(bits(SN)-5) - 1 if bits(SN) > 4 R=
20;<o:p></o:p></i></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">As per my understanding, we should use the be=
low ‘p’ values at compressor [for SN Encoding]<o:p></o:p></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-.25in;mso-list:l0 leve=
l1 lfo2"><![if !supportLists]><span style=3D"mso-list:Ignore">-<span style=
=3D"font:7.0pt "Times New Roman""> =
</span></span><![endif]>p=3D-1, if packets are received in-order<o:p></o:p=
></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-.25in;mso-list:l0 leve=
l1 lfo2"><![if !supportLists]><span style=3D"mso-list:Ignore">-<span style=
=3D"font:7.0pt "Times New Roman""> =
</span></span><![endif]>p=3D2^(k-2)-1, if packets are received out-of-orde=
r<o:p></o:p></p>
<p class=3D"MsoNormal">at decompressor<o:p></o:p></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-.25in;mso-list:l0 leve=
l1 lfo2"><![if !supportLists]><span style=3D"mso-list:Ignore">-<span style=
=3D"font:7.0pt "Times New Roman""> =
</span></span><![endif]>p =3D 1 if bits(SN) <=3D 4<o:p></o:p></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-.25in;mso-list:l0 leve=
l1 lfo2"><![if !supportLists]><span style=3D"mso-list:Ignore">-<span style=
=3D"font:7.0pt "Times New Roman""> =
</span></span><![endif]>p =3D 2^(bits(SN)-5) - 1 if bits(SN) > 4<o:p></=
o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal"><b><u>Queries<o:p></o:p></u></b></p>
<p class=3D"MsoListParagraph" style=3D"margin-left:.25in;text-indent:-.25i=
n;
mso-list:l3 level1 lfo3">
<![if !supportLists]><span style=3D"mso-list:Ignore">1.<span style=3D"font=
:7.0pt "Times New Roman"">
</span></span><![endif]>Is my understanding is right?<o:p></o:p></p>
<p class=3D"MsoListParagraph" style=3D"margin-left:.25in;text-indent:-.25i=
n;
mso-list:l3 level1 lfo3">
<![if !supportLists]><span style=3D"mso-list:Ignore">2.<span style=3D"font=
:7.0pt "Times New Roman"">
</span></span><![endif]>What is the value of ‘p’ for Profile-3=
at compressor and decompressor? Is it same as above?<o:p></o:p></p>=
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Thanks for your support.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Regards,<o:p></o:p></p>
<p class=3D"MsoNormal">Anil Kumar Maguluri<o:p></o:p></p>
</div>
<br>
<hr>
<font face=3D"Arial" color=3D"Black" size=3D"3">This Email may contain con=
fidential or privileged information for the intended recipient (s) If you =
are not the intended recipient, please do not use or disseminate the infor=
mation, notify the sender and delete it from
your system.<br>
</font>
<BR>
______________________________________________________________________<BR>=
</body>
</html>
--_000_903D13EA90218E43BA0881BC8B569C7D230903D6BLRINMSMBX01bgl_--
--===============1929575011==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
_______________________________________________
Rohc mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/rohc
--===============1929575011==--