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Re: [Lksctp-developers] SCTP Multihoming: Association Bouncing
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From: Wei Y. <yj...@cn...> - 2011-01-10 03:06:04
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> Hi all,
> I am having a multihoming scenario. Client has two IP's as well as
> server has two IP's(primary and secondary). Following actions are now
> happening:
>
> 1) After Association is established, we block the Secondary to Secondary
> path
> 2) Now, we block the Server's Secondary to Client's primary path.
>
> Only REMAINING connections are
> Server Client
> Prim ----------------------Prim
> Prim-----------------------Sec
>
> It means Server's secondary is isolated, Now, if I deactivate and then
> activate the association again, the association is bouncing. Server is
> sending ABORT even after association is established.
It is very strange. can you offer the tcpdump's output of both
Prim and Sec path?
> Kindly help us in understanding why this is happening?
>
> Regards,
> Rahul Goyal
>
>
>
>
> From: Rahul32 G <rah...@tc...>
>
> To: Wei Yongjun <yj...@cn...>
>
> Cc: Michael Tüxen <Mic...@lu...>, lks...@li...
>
> Date: 01/05/2011 04:33 PM
>
> Subject: Re: [Lksctp-developers] SCTP Multihoming: HeartBeat Query
>
>
>
>
>
>
> Hi,
> Thanks a lot for your help. I am facing one more problem. I
> have a multihoming scenario where client and server both have two ip's
> (primary and secondary). and all the paths are blocked by network policy.
> Now, when we activate only the secondary(server) to primary(client) path,
> it shows the association as active and then association is bouncing. I am
> wondering why is it happening?
>
> Thanks,
> Rahul Goyal
>
>
>
>
> From: Wei Yongjun <yj...@cn...>
>
>
> To: Michael Tüxen <Mic...@lu...>
>
>
> Cc: lks...@li...
>
>
> Date: 01/04/2011 06:50 AM
>
>
> Subject: Re: [Lksctp-developers] SCTP Multihoming: HeartBeat Query
>
>
>
>
>
>
>
>
>> On Dec 31, 2010, at 3:11 PM, Chandan12 K wrote:
>>
>>> Thanks Christian. I checked the code and found out that the RTO init
>>> variable is 3 second by default.
>>>
>>> It seems that the first heart beat on primary path is set to = default
>>> hb_interval (default 30 sec)+ RTO (default 3 sec) and on the secondary
>>> path it sends the heart beat immediately. And the funny part is that I
> am
>>> yet to find it in the code/RFCb :-)
>> Maybe it is sent immediately because it is a HB for path verification.
>> Not sure about Linux, but FreeBSD sends these path verification HB
>> immediately.
> Linux also sent immediately because it is a HB for path verification.
> In each RTO, a probe HB may be sent on an active UNCONFIRMED
> path in an attempt to move it to the CONFIRMED state.
>
>
>
>> Best regards
>> Michael
>>> Thanks,
>>> Chandan Kumar
>>>
>>>
>>>
>>> From:
>>> Christian Schoch <e03...@st...>
>>> To:
>>> lks...@li...
>>> Cc:
>>> Chandan12 K <cha...@tc...>
>>> Date:
>>> 12/31/2010 07:03 PM
>>> Subject:
>>> Re: [Lksctp-developers] SCTP Multihoming: HeartBeat Query
>>>
>>>
>>>
>>> Hi Chandan,
>>>
>>>> Thanks Bhaskar for the Info. However, we are not able to understand why
>>>> the first heart beat on primary path is going after 33 second whereas
> in
>>>> case of secondary it's going after 2 second (the updated time interval
>>>> value).
>>>>
>>>> Is it an expected behavior that if the default time interval set to 30
>>> (as
>>>> per RFC) the very first heart beat will take the default values rather
>>>> than the value set by the application. And in case of secondary path it
>>>> takes updated time interval ?
>>>>
>>> Under normal situations, the heartbeat interval for each transport
>>> should be calculated as noted and is based on the RTO of the transport
>>> (if no DATA is sent).
>>>
>>> interval = RTO + (+- 50% RTO) + hb_interval;
>>> [interval] = [0,5*RTO+hb_interval , 1,5*RTO+hb_interval]
>>>
>>> BUT, the first interval is depending on the RTO only (see transport.c
>>> ~line 600 at 2.6.36). so it calculates (with RTO_initial as RTO):
>>>
>>> interval = RTO_init +-50% RTO_init
>>>
>>>
>>> So for lowering the first Heartbeat, you should decrease RTO_initial
>>> value which can also be adjusted by setsockoption.
>>>
>>> As an alternative try to the set the SPP_HB_DEMAND flag of spp_flags,
>>> which should send you the heartbeat.
>>>
>>> Regards,
>>> Christian
>>>
>>>
>>>
>>>
>>>> PS: In our case after the association is established the application
>>> does
>>>> not transmit any data chunks from either side. And we are wondering the
>>>> why heart beats are sent differently for primary and secondary paths.
>>>>
>>>> Thanks,
>>>> Chandan Kumar
>>>>
>>>>
>>>>
>>>>
>>>> Hello,
>>>>
>>>> We have a sctp multihoming setup where no data is being transferred.
> The
>>>> set up consists of primary ip at server (PS_ip) and on client side
>>>> primary(PC_ip),secondary(SC_ip).
>>>>
>>>> Once the association establishes the application sets hb_interval
> value
>>>> to 2000msecs using setsockopt function.
>>>>
>>>>
>>>> After deactivating and activating associations from the server
> following
>>>> is observed.
>>>>
>>>> The first heartbeat(HB) is sent from PS_ip to PC_ip around 33secs after
>>>> 4-way handshake. However, the first HB is sent from PS_ip to SC_ip
>>> almost
>>>> immediately after 4-way handshake.
>>>> Subsequently the HBs are sent from PS_ip to both PC_ip and SC_ip at
>>>> intervals of 2secs.
>>>>
>>>> Questions:-
>>>>
>>>> 1. Why would there be such a difference for the 2 paths ("Path1: PS_ip
>>> to
>>>> PC_ip" and "Path2: PS_ip to SC_ip") for the first HB being sent?
>>>> 2. Is this an expected behaviour?
>>>> 3. On what parameter does sending of first HB depend? Does it depend on
>>>> hb_interval variable? In our case we found that the hb_interval of
>>>> sctp_transport structure for both the paths has same value of
> 2000msecs.
>>>>
>>>> Currently we are using Linux kernel 2.6.10 and patched back the
>>>> Multi-homing from upstream kernel.
>>>>
>>>>
>>>> Your /proc/sys/net/sctp/hb_interval is still at the default 30 seconds.
>>>> Changing it (via sysctl) should decrease the hb interval on the primary
>>>> path.
>>>>
>>>>
>>>>
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> ------------------------------------------------------------------------------
>
>
>>>> Learn how Oracle Real Application Clusters (RAC) One Node allows
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> ------------------------------------------------------------------------------
>
>
>>> Learn how Oracle Real Application Clusters (RAC) One Node allows
> customers
>>> to consolidate database storage, standardize their database environment,
> and,
>>> should the need arise, upgrade to a full multi-node Oracle RAC database
>>> without downtime or disruption
>>> http://p.sf.net/sfu/oracle-sfdevnl
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>>
> ------------------------------------------------------------------------------
>
>
>> Learn how Oracle Real Application Clusters (RAC) One Node allows
> customers
>> to consolidate database storage, standardize their database environment,
> and,
>> should the need arise, upgrade to a full multi-node Oracle RAC database
>> without downtime or disruption
>> http://p.sf.net/sfu/oracle-sfdevnl
>> _______________________________________________
>> Lksctp-developers mailing list
>> Lks...@li...
>> https://lists.sourceforge.net/lists/listinfo/lksctp-developers
>>
> ------------------------------------------------------------------------------
>
>
> Learn how Oracle Real Application Clusters (RAC) One Node allows customers
> to consolidate database storage, standardize their database environment,
> and,
> should the need arise, upgrade to a full multi-node Oracle RAC database
> without downtime or disruption
> http://p.sf.net/sfu/oracle-sfdevnl
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> https://lists.sourceforge.net/lists/listinfo/lksctp-developers
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> ------------------------------------------------------------------------------
>
> Learn how Oracle Real Application Clusters (RAC) One Node allows customers
> to consolidate database storage, standardize their database environment,
> and,
> should the need arise, upgrade to a full multi-node Oracle RAC database
> without downtime or disruption
> http://p.sf.net/sfu/oracle-sfdevnl
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> Lksctp-developers mailing list
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