[sctp-dev] SCTP API - PPI

[Christopher Hegarty - Sun Microsystems Ireland]

Hi Tomas,

Great, you are actually using the PPID in some prototypes. I'll add a 
getter/setter to MessageInfo for this. I hope to have an updated javadoc 
early next week.

-Chris.

Kukosa, Tomas wrote:
> 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