[sctp-dev] Performance degradation when changing from primary to backup path

[Chris Hegarty]

Bruno,

Thanks for the follow up on the list. Good to hear that all is working 
well again.

-Chris.

On 05/08/2013 10:46 PM, Bruno Sousa wrote:
> Dear list
>
> I'm sorry for the 'noise.
>
> After performing reboot on the machines, this problem got away.
>
> I've also deactivated the use of crc32 on the sctp module.
>
> Best Regards,
> Bruno Sousa
>
> On 5/6/13 2:44 PM, Bruno Sousa wrote:
>> Dear SCTP users and developers
>>
>> I'm Bruno Sousa and I'm working with SCTP due to its multihoming support.
>>
>> Currently I've an application for file transfer using SCTP and JDK7.
>> I've two linux servers multihomed where each one has two ethernet
>> interfaces.
>> File transfer starts with primary path in /eth0/ interface, and after
>> a certain period I've programmed failures using iptables, to drop
>> packet on server B coming from server A (srv_A):
>> /iptables -I INPUT -i eth0 -s IP_eth0_srv_A -j DROP //
>> //iptables -A OUTPUT -d IP_eth0_srv_A -j DROP /
>>
>> This works and SCTP detects failures on primary path in eth0, as expected.
>>
>> I've implement handlers to receive and treat SCTP events, namely:
>>
>> /*PeerAddressChangeNotification.AddressChangeEvent.ADDR_UNREACHABLE*/
>>
>> With which I'm performing the change of Primary addresses, as follows:
>>
>> /try{//
>> // auxChannel.setOption(SctpStandardSocketOptions.SCTP_PRIMARY_ADDR,
>> remote.toInetSocketAddr());//
>> //
>> ////Change remote primary address//
>> //auxChannel.setOption(SctpStandardSocketOptions.SCTP_SET_PEER_PRIMARY_ADDR,
>> auLocal );//
>> //}catch(Exception ex){ //
>> // // Treat Exception//
>> //}/
>>
>> The code works for changing primary addresses, as I've checked in
>> //proc/net/sctp/assocs/.
>>
>> Nonetheless, the problem, is that after changing address, file
>> transfer get very slow on backup path.
>> Using Wireshark I've checked that SCTP DATA messages and respective
>> ACKs are not sent 'sequentially' as with primary path.
>> SCTP Data is sent and only after a certain time it is sent again.
>>
>> Is there any reason for such performance degradation?
>>
>> What can I do, to improve performance?
>>
>> Thanks in advance,
>> Bruno Sousa
>>
>> My Kernel is: 2.6.32-5 and I've also tried on 3.2.0
>> Lksctp-tools: 1.0.11+dfsg-1 and 1.0.11+dfsg-2
>>
>>
>>
>>
>>
>>
>