[sctp-dev] Setting "Traffic Class" to a SctpChannel

[Chris Hegarty]

On 8/1/2011 9:29 AM, Michal Lefler wrote:
> Chris.
> Thanks for your response.
> We are indeed interested in configuring the different SCTP parameters
> since it makes a significant difference in how the associations function
> in different scenarios (channel failover etc.).
> SCTP is very sensitive to the network condition and we interconnect
> different associations with different network condition, so we should be
> able to configure profile per each remote association.
> We would like to configure each server accepted channel differently. Is
> this possible?

Socket-level options can be configured per accepted channel, but I'm not 
sure if this is what you are really looking for.

> We would like to be able to configure the traffic class.

Currently this is not supported, but I don't see any problem with 
supporting it. I'll file a bug in our bug database for this.

>
> In addition, we are very interested to be able to configure the
> following parameters:
> * net.sctp.sack_timeout
> * net.sctp.prsctp_enable
> * net.sctp.addip_enable
> * net.sctp.rto_beta_exp_divisor
> * net.sctp.rto_alpha_exp_divisor
> * net.sctp.cookie_preserve_enable
> * net.sctp.hb_interval
> * net.sctp.max_init_retransmits
> * net.sctp.path_max_retrans
> * net.sctp.rcvbuf_policy
> * net.sctp.sndbuf_policy
> * net.sctp.association_max_retrans
> * net.sctp.max_burst
> * net.sctp.valid_cookie_life
> * net.sctp.rto_max
> * net.sctp.rto_min
> * net.sctp.rto_initial
>
> and in a lower priority:
> * net.sctp.sctp_wmem
> * net.sctp.sctp_rmem
> * net.sctp.sctp_mem

These sysctl variables are not part of any RFC and I guess are 
implementation specific to LKSCTP. Most are not appropriate to a higher 
level API like Java, we could not provide consistent cross platform 
support. Also it is not clear to me the implication of setting some of 
these variables on a live process, e.g. can you enable/disable Dynamic 
Address Reconfiguration support per association?

-Chris.

>
> Thanks,
> Michal.
>
>
> -----Original Message-----
> From: Chris Hegarty [mailto:chris.hegarty at oracle.com]
> Sent: Tuesday, July 12, 2011 12:35 PM
> To: Michal Lefler
> Cc: sctp-dev at openjdk.java.net
> Subject: Re: [sctp-dev] Setting "Traffic Class" to a SctpChannel
>
> On 07/ 7/11 03:09 PM, Michal Lefler wrote:
>> Hi.
>> Is there a way in which I can set the traffic class to a
>> com.sun.nio.sctp.SctpChannel instance?
> Currently there is no way of setting the traffic class on an
> SctpChannel. In our experience traffic class was not widely used and
> there were no requests for supping it in SCTP.
>
> Since socket options are supported through the SctpSocketOption
> interface and the channel can report its supported options,
> supportedOptions(), then it may be possible to support implementation
> specific options in the future.
>
> Is this something that is really important to you?
>
> -Chris.
>
>> I mean something similar to the TCP option:
>> java.net.Socket.setTrafficClass(int tc);
>>
>> Thanks,
>> Michal.
>>