RE: [Tsvwg] End point and association Address conflict

my comments..

-----Original Message-----
From: Randall Stewart [mailto:randall@stewart.chicago.il.us]
Sent: Friday, April 26, 2002 9:45 AM
To: Balani, Sandeep
Cc: Ivan.Arias-Rodriguez@nokia.com; qxie1@email.mot.com; Khan, Mohammad;
tsvwg@ietf.org
Subject: Re: [Tsvwg] End point and association Address conflict

"Balani, Sandeep" wrote:
> 
> Hi All,
>   My comments inline...
> 
> -sandeep
> 
> -----Original Message-----
> From: Randall Stewart [mailto:randall@stewart.chicago.il.us]
> Sent: Friday, April 26, 2002 6:31 AM
> To: Ivan.Arias-Rodriguez@nokia.com
> Cc: s_balani@trillium.com; qxie1@email.mot.com; mo_khan@trillium.com;
> tsvwg@ietf.org
> Subject: Re: [Tsvwg] End point and association Address conflict
> 
> Ivan.Arias-Rodriguez@nokia.com wrote:
> >
> >         Hi Sandeep!
> >
> >         See my comment inline...
> >
> > > hi all,
> > >
> > > My comments inline,
> > >
> > >
> > >       Randy, see my comment inline...
> > >
> > > > Ivan.Arias-Rodriguez@nokia.com wrote:
> > > > >
> > > > >         Hi all!
> > > > >
> > > > >         Well, now I realized that I had a somehow different
> > > > view about what was a legal addition... thanks for your comments.
> > > > >
> > > > >         Now I have another doubt... Imagine that we have an
> > > > endpoint E1 with addresses IPa, IPb and port 1. We have an
> > > > association A1 that only uses IPa, whose peer is IPz and port
> > > > 65535. Thus the association A1 can be represented as [(IPa;
> > > > Port1), (IPz; Port 65535)]. What happens now if we receive an
> > > > INIT from IPz/65535 directed to IPb/1?
> > > >
> > > > A question...
> > > >
> > > > Why did you not include IPb in the INIT or INIT-ACK that
> > > setup A1. You
> > > > are
> > > > supposed to tell the peer of all your addresses that are
> > > bound to your
> > > > endpoint. I think this is the big flaw in your question..
> > >
> > >       I did, but later on I deleted it using the AddIP
> > > extension... :-) So
> > > now I don't use it anymore...
> > >
> > > [ sandeep ] I think this is very interesting proble :-)
> > >  What i think we can do is When u are doing DELETEIP for IPb, If no
> > > association is using IPb as source address we should remover IPb from
> > > Endpoint E1. This way we will not have any such problem.
> > >
> > > What do u think ????
> >
> >         No, I don't think this is a good solution... Remember that there
> can be >many associations in that endpoint, and that they might be using
IPb
> as A1 did >>once... I don't think you can erase that address from the
> endpoint...
> 
> Hmm.. maybe the real solution is you MUST NOT use the DELETE unless
> you are also deleting it from the endpoint.
> 
> So... if you do a DELETE IP-B you MUST first delete it from the
> endpoint. Then you MAY delete it from any association... ones you
> don't delete it from will have to have a variant list of addresses
> that it has ...
> 
> That way everything still works for those that DO NOT delete IP-B and
> your problem goes away...
> 
> Of course your problem STILL exists when you HOT-PLUG in a card
> and have an existing association and NO ADD-IP extension...
> 
> [ Sandeep ]   Can we delete an IP address from an Endpoint first & then
> delete It from Association. According  to the procedure, Between the time
we
> have send ASCONF( Delete IPb) & the time we receive ASCONF-ACK(Delete IPb)
> we should accept all packets destined to IPb ????
> 

I would think it would be ok.. remember the Endpoint is only
used for basic things like new assocaitions... the actual
"what addresses are in the association" can be kept in association
specific instances...

[ Sandeep ] I probably don't understand this point.  But i don't agree with
this 100%.  
This may be very implemenataion specific but For all incoming DATAGRAM i
should check if the Endpoint exist or Not, If Endpoint does not exist i will
not proceed .. So in case i deleted the IPb Address from the Endpoint, I
will never be able to accept the packet for that association which has IPb
in its source address. 

Moreover i think that its illegal to have a Source Address not present in
Endpoint & present in Association ( if that's the case ) ???  

> Also deleting an IP address from an Endpoint means, Deleting it from
> multiple associations simultaneously ( Or One-By-One ) , What if on One
> association  this DeleteIP procedure fails ???

Well.. I don't see an issue.. so you are stuck with a deleted IP address
in your assocaition. 

A) Chances are you won't receive packets on it (since it is off the
   machine).

B) If it is NOT off the machine your code STILL should work in that
   it had better be keeping a list of addresses on the association that
   are valid... (when there is a deviant case such as this).

> 
> This may be prevented if We can put such recommendation which Randall
> indicated in earlier mail, I.e. DELETEIP procedure is only recommended in
> cases when NIC card assocaited with that Ip address is actually going
down.
> In that case we have to remove IP address from  Association & Endpoint .

Yes.. but you still can end up with a IP address stuck in your
association if the peer does not do ADD-IP.. 

> 
> I am really not sure whether the statment I made in previous mail should
be
> assumed TRUE/Correct  : "  An Association Can Use SUBSET of IP Addresses
> from its Endpoint ".
> 
> What do u guys think ??????

I think you CAN do this but it WILL cause you grief.. if by using
a subset you are saying making a decision that I am NOT going
to include IP-C in my address list (even though it is reachable
and should have normally been included).

R

-- 
Randall R. Stewart
randall@stewart.chicago.il.us 815-342-5222 (cell phone)

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