Re: Supporting 4 way connections in LKSCTP

[Michael Tuexen]

On Dec 4, 2013, at 5:48 PM, David Laight <David.Laight@xxxxxxxxxx> wrote:

>> The point is that address scoping should be used. When sending an
>> INIT from 10.10.10.1 to 10.10.10.4 you should not list 192.168.1.1,
>> since you are transmitting an address to a node which might or might
>> not "be in the same scope".
> 
> You might have two machines that are connected via the public
> internet and also via a private network.
> The two sets of cabling being completely separate giving you
> resilience to network failure.
> In which case you definitely don't want address scoping.
Well, if you give the SCTP stack a hint when initiating
the association, it can do the right thing.
Calling sctp_connect(private_address) should work. It will list
the public address without any problems.
One can debate that sctp_connectx(private_address, public_address)
will result in sending an INIT to the public_address listing the
private one. However, calling sctp_connect(public_address) should
not list the private_address.

Best regards
Michael
> 
> While you may not want the SCTP traffic on the public network
> itself, it could easily be routed separately.
> 
> We have systems that 'sort of' designate one interface for SIP/RTP
> and the other for 'management'. They might run M3UA/SCTP but no one
> has really thought enough about which interface(s) the M3UA traffic
> should use.
> (Think of an ISUP/SIP gateway using M3UA for ISUP signalling.)
> 
> 	David
> 
> 
> 
> 

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