[sctp-dev] SCTP API - PPI

[Kukosa, Tomas]

Hi Chris,

I have understood RFC 4960 (see PPI definition below) in another way.
It is not for future usage/flexibility. It is for usage of application
layer to discern between various kinds of DATA chunks.

Curently we use it just in our prototypes where we use PPI 13 (for
H.323) and few proprietary PPIs.

We use SCTP library from http://i1.dk/JavaSCTP/ but we are looking
forvard to test SCTP in Java. :-)

Best regards,
  Tomas

--------------------
RFC 4960 snip

Payload Protocol Identifier: 32 bits (unsigned integer)

      This value represents an application (or upper layer) specified
      protocol identifier.  This value is passed to SCTP by its upper
      layer and sent to its peer.  This identifier is not used by SCTP
      but can be used by certain network entities, as well as by the
      peer application, to identify the type of information being
      carried in this DATA chunk.  This field must be sent even in
      fragmented DATA chunks (to make sure it is available for agents in
      the middle of the network).  Note that this field is NOT touched
      by an SCTP implementation; therefore, its byte order is NOT
      necessarily big endian.  The upper layer is responsible for any
      byte order conversions to this field.

      The value 0 indicates that no application identifier is specified
      by the upper layer for this payload data.


 

> -----Original Message-----
> From: Christopher.Hegarty at Sun.COM 
> [mailto:Christopher.Hegarty at Sun.COM] 
> Sent: Tuesday, December 09, 2008 4:57 PM
> To: Kukosa, Tomas
> Cc: sctp-dev at openjdk.java.net
> Subject: Re: [sctp-dev] SCTP API - PPI
> 
> Hi Tomas,
> 
> The Payload Protocol ID has been included in the protocol for future 
> flexibility.  It is envisioned that the functions of protocol 
> identification and port number multiplexing will not be as closely 
> linked in the future as they are currently.
> 
> The current draft does not have support for getting/setting 
> the Payload 
> Protocol Identifier, PPID. You are correct, if we were to 
> support this 
> then it would be through a getter/setter in the MessageInfo class.
> 
> Do you have a specific requirement for the PPID?
> 
> Regards,
> -Chris.
> 
> On 12/09/08 14:42, Kukosa, Tomas wrote:
> > Hi,
> > 
> > looking to proposed API I can not see any method to set/get Payload
> > Protocol Identifier.
> > I would expect it e.g. in the MessageInfo class. Have I 
> missed anything?
> > 
> > Best regards,
> >   Tomas
>