Subject: [rohc] State related to SIP/SDP

From: "Achuth Kamath" <[email-masked]>
Date: Thu, 24 Mar 2005 14:38:35 +0530

Hi,
   I have a doubt regarding the state information sending in Sigcomp
message. This is in the context of Sigcomp for SIP/SDP. SIP/SDP already
requires a dictionary which is stored as a state item. Now, we will use
some compression algorithm on top of it, say DEFLATE, we send the
bytecode in first message and ask the decompressor to save it. Now, next
time onwards how do we instruct the remote decompressor to use two
states (one state for SIP/SDP, another for DEFLATE) ? Or rather how do
we send two state identifiers?
 
Thanks in advance!
 
Best Regards,
Achuth
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---

From: Herve Siegrist <[email-masked]>
Date: Thu, 24 Mar 2005 11:24:35 +0100

You don't need to handle two states: the first time around, your
SigComp message holds the bytecode which, in its initialization
sequence, makes a StateAccess to access the SIP dictionary. When
execution is completed, the EndMessage instruction places the entire
UDVM memory (minus the first 64 bytes) in the state it creates.

As a result, this state also holds the SIP dictionary which then does
not need to be loaded again when the next message is received... When
this next message arrives, it does not hold the bytecode anymore but
simply a reference to your saved state. Its instruction location
directs the UDVM to start executing the bytecode after its init
sequence, so the StateAccess instruction is not executed again and you
do not reload the SIP dictionary which is already there (that is, of
course, if you follow the guidelines in the SigComp user guide to
handle dictionaries)...

Herve.

Achuth Kamath wrote:

Hi,

I
have a
doubt regarding the state information sending in Sigcomp
message. This is in the context of Sigcomp
for
SIP/SDP. SIP/SDP already requires a dictionary which is stored as a
state item.
Now, we will use some compression algorithm on top of it, say DEFLATE,
we send
the bytecode in first message and ask the decompressor to save it. Now, next time onwards
how do we
instruct the remote decompressor to use
two states (one
state for SIP/SDP, another for DEFLATE) ? Or
rather
how do we send two state identifiers?

Thanks in advance!

Best Regards,

Achuth

---

From: "Achuth Kamath" <[email-masked]>
Date: Thu, 24 Mar 2005 17:35:37 +0530

Thanks a lot, Herve !!!
 
Best Regards,
Achuth
 
-----Original Message-----
From: Herve Siegrist [mailto:[email-masked]] 
Sent: Thursday, March 24, 2005 3:55 PM
To: Achuth Kamath
Cc: [email-masked]
Subject: Re: [rohc] State related to SIP/SDP
 
You don't need to handle two states: the first time around, your SigComp
message holds the bytecode which, in its initialization sequence, makes
a StateAccess to access the SIP dictionary. When execution is completed,
the EndMessage instruction places the entire UDVM memory (minus the
first 64 bytes) in the state it creates. 

As a result, this state also holds the SIP dictionary which then does
not need to be loaded again when the next message is received... When
this next message arrives, it does not hold the bytecode anymore but
simply a reference to your saved state. Its instruction location directs
the UDVM to start executing the bytecode after its init sequence, so the
StateAccess instruction is not executed again and you do not reload the
SIP dictionary which is already there (that is, of course, if you follow
the guidelines in the SigComp user guide to handle dictionaries)...

Herve.

Achuth Kamath wrote: 
Hi,
 
Thanks in advance!
 
Best Regards,
Achuth

  _____