Subject: RE: [Sigtran] RE: sg-sg communication

From: "Tolga Asveren" <[email-masked]>
Date: Thu, 30 May 2002 13:34:16 -0400

Javier,

> -----Original Message-----
> From: Javier Pastor-Balbas (ECE)
> [mailto:[email-masked]]
> Sent: Thursday, May 30, 2002 1:13 PM
> To: 'Tolga Asveren'
> Subject: RE: [Sigtran] RE: sg-sg communication
>
>
> Tolga,
>
> IPSP communication was made to allow that two ASes can talk to
> each other. If one AS wants to talk to a SG it should use AS-SG
> communication.
[TOLGA] You should make up your mind, is IPSP AS-AS or ASP-ASP? There is a
huge difference between those two approaches. Basically this is the main
difference between "double-ended" and "single-ended" approaches, it is not
just whetehr ASPUP (or ASPAC) is sent from one side or from two sides.
>
> BTW. Could you explain me what serving one AS means for you? :-)
[TOLGA] It means just handling traffic for it, not being a part of it. AS is
nothing else than a traffic range. If you think it corresponds to something
physicall, I strongly disagree. On the other hand SG really consist of SGPs,
and so indirectly corresponds to a physicall entity.
>
> Cheers // Javier.
>
> > -----Original Message-----
> > From: Tolga Asveren [mailto:[email-masked]]
> > Sent: Thursday, May 30, 2002 7:21 PM
> > To: [email-masked]
> > Subject: RE: [Sigtran] RE: sg-sg communication
> >
> >
> > Javier,
> >
> > AS is not consisting of ASPs (or IPSPs), ASPs are just
> > serving one or more
> > AS. It is for sure that AS does not correspond to something
> > physical but is
> > just an abstraction. The relationship between AS/ASP and
> > SG/SGP is not the
> > same. Anyway, this is not the main discussion. How IPSPs are going to
> > communicate with SGPs? That is the main question. Because
> > both of those are
> > physically existing and are exchanging messages.
> >
> >    Tolga
> >
> > > -----Original Message-----
> > > From: Javier Pastor-Balbas (ECE)
> > > [mailto:[email-masked]]
> > > Sent: Thursday, May 30, 2002 12:30 PM
> > > To: 'Tolga Asveren'; [email-masked]
> > > Subject: RE: [Sigtran] RE: sg-sg communication
> > >
> > >
> > > Hi Tolga,
> > >
> > > An AS is basically what you call an SPC (Cosidering SPC
> > > grnularity) in IP. That SPC can talk to a SG and it can be
> > > implemented as a set of ASP for redundancy purposes being able of
> > > being configured following the n+k model defined in the RFC. But
> > > also that AS can talk with another AS and it can be implemented
> > > by one or more IPSPs (or ASP with the capability of talking to
> > > another peer ASP).
> > >
> > > An AS has sense and it can be composed of ASPs (when talking with
> > > SG), IPSPs (Talking with other ASes) or ASP/IPSPs (talking
> > with both).
> > >
> > > And the realisation of an AS is the M3UA peer of another AS or
> > > SG. For me, it is easier to understand it in the simple case:
> > > when there is only one ASP per AS and an SGP per SG. The ASP is
> > > the implementation of the AS. In this case you can see that SG
> > > (non distributed SG) is talking with an AS (a non distributed
> > > AS). I would conclude with the example:
> > >
> > >  - AS is peer of an SG
> > >  - SGP is peer of ASP
> > >
> > >
> > > Cheers // Javier.
> > >
> > > > -----Original Message-----
> > > > From: Tolga Asveren [mailto:[email-masked]]
> > > > Sent: Thursday, May 30, 2002 6:13 PM
> > > > To: [email-masked]
> > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > >
> > > >
> > > > Javier,
> > > >
> > > > Because in my opinion they are not peers. SG is consisting of
> > > > SGPs, but AS
> > > > is not consisting of ASPs. AS does not correspond to
> > > > something physical and
> > > > is a pure abstraction.
> > > >
> > > >      Tolga
> > > >
> > > > > -----Original Message-----
> > > > > From: Javier Pastor-Balbas (ECE)
> > > > > [mailto:[email-masked]]
> > > > > Sent: Thursday, May 30, 2002 11:52 AM
> > > > > To: 'Tolga Asveren'; [email-masked]
> > > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > > >
> > > > >
> > > > > Tolga,
> > > > >
> > > > > Why don't you see SG and AS as peers ?? Could you explain more?
> > > > >
> > > > > Cheers //Javier.
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Tolga Asveren [mailto:[email-masked]]
> > > > > > Sent: Thursday, May 30, 2002 6:00 PM
> > > > > > To: [email-masked]
> > > > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > > > >
> > > > > >
> > > > > > Javier,
> > > > > >
> > > > > > Then you need to put both IPSP and ASP functionality in your
> > > > > > node. Isn't
> > > > > > this against your strategy of having one entity? I also
> > > > > > strongly disagree to
> > > > > > see AS and SGs as peers, in my opinion they aren't.
> > > > > >
> > > > > >    Tolga
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Javier Pastor-Balbas (ECE)
> > > > > > > [mailto:[email-masked]]
> > > > > > > Sent: Thursday, May 30, 2002 11:39 AM
> > > > > > > To: 'Tolga Asveren'; [email-masked]
> > > > > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > > > > >
> > > > > > >
> > > > > > > Hi Tolga,
> > > > > > >
> > > > > > > My understanding is that you have an IP node, what we
> > > > call AS. An
> > > > > > > AS can communicate to both: another AS or an SG. If
> > the AS is
> > > > > > > communicating to an SG you are using the AS-SG
> > communication. If
> > > > > > > the AS is talking to another AS you use the IPSP
> > > > communication.  :-D
> > > > > > >
> > > > > > > Cheers // Javier.
> > > > > > >
> > > > > > > > -----Original Message-----
> > > > > > > > From: Tolga Asveren [mailto:[email-masked]]
> > > > > > > > Sent: Thursday, May 30, 2002 5:43 PM
> > > > > > > > To: [email-masked]
> > > > > > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > > > > > >
> > > > > > > >
> > > > > > > > Javier,
> > > > > > > >
> > > > > > > > For SGPF+ASPF case, we have different opinions because we
> > > > > > > > have different
> > > > > > > > understanding of what a protocol should define and what it
> > > > > > > > shouldn't. But
> > > > > > > > apart from this, if IPSP can't speak to SGPs as
> > ASP, it won't
> > > > > > > > be something
> > > > > > > > very usefull for the reason Brian pointed out.
> > > > > > > >
> > > > > > > >    Tolga
> > > > > > > >
> > > > > > > > > -----Original Message-----
> > > > > > > > > From: Javier Pastor-Balbas (ECE)
> > > > > > > > > [mailto:[email-masked]]
> > > > > > > > > Sent: Thursday, May 30, 2002 11:25 AM
> > > > > > > > > To: 'Tolga Asveren'; [email-masked]
> > > > > > > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Hi Tolga,
> > > > > > > > >
> > > > > > > > > See below,
> > > > > > > > >
> > > > > > > > > > -----Original Message-----
> > > > > > > > > > From: Tolga Asveren [mailto:[email-masked]]
> > > > > > > > > > Sent: Thursday, May 30, 2002 5:35 PM
> > > > > > > > > > To: [email-masked]
> > > > > > > > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Hi Javier,
> > > > > > > > > >
> > > > > > > > > > > -----Original Message-----
> > > > > > > > > > > From: Javier Pastor-Balbas (ECE)
> > > > > > > > > > > [mailto:[email-masked]]
> > > > > > > > > > > Sent: Thursday, May 30, 2002 11:16 AM
> > > > > > > > > > > To: 'Tolga Asveren'; [email-masked]'
> > > > > > > > > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Hi Tolga,
> > > > > > > > > > >
> > > > > > > > > > > Comments below...
> > > > > > > > > > >
> > > > > > > > > > > > -----Original Message-----
> > > > > > > > > > > > From: Tolga Asveren [mailto:[email-masked]]
> > > > > > > > > > > > Sent: Thursday, May 30, 2002 5:15 PM
> > > > > > > > > > > > To: [email-masked]
> > > > > > > > > > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Javier,
> > > > > > > > > > > >
> > > > > > > > > > > > > -----Original Message-----
> > > > > > > > > > > > > From: Javier Pastor-Balbas (ECE)
> > > > > > > > > > > > > [mailto:[email-masked]]
> > > > > > > > > > > > > Sent: Thursday, May 30, 2002 10:53 AM
> > > > > > > > > > > > > To: 'Tolga Asveren'; [email-masked]
> > > > > > > > > > > > > Subject: RE: [Sigtran] RE: sg-sg communication
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi Tolga,
> > > > > > > > > > > > >
> > > > > > > > > > > > > A small comment on yours...
> > > > > > > > > > > > >
> > > > > > > > > > > > > > -----Original Message-----
> > > > > > > > > > > > > > From: Tolga Asveren
> > [mailto:[email-masked]]
> > > > > > > > > > > > > > Sent: Thursday, May 30, 2002 4:56 PM
> > > > > > > > > > > > > > To: [email-masked]
> > > > > > > > > > > > > > Subject: [Sigtran] RE: sg-sg communication
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Reshma,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > -----Original Message-----
> > > > > > > > > > > > > > > From: reshma
> > [mailto:[email-masked]]
> > > > > > > > > > > > > > > Sent: Thursday, May 30, 2002 10:35 AM
> > > > > > > > > > > > > > > To: Tolga Asveren
> > > > > > > > > > > > > > > Cc: [email-masked]
> > > > > > > > > > > > > > > Subject: sg-sg communication
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi  Tolga,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >     Thanks for your reply some more
> > doubts :-(
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >  [Reshma] Okay now its clear. But
> > > > how does SG1
> > > > > > > > > > knows whether
> > > > > > > > > > > > > > > the data is
> > > > > > > > > > > > > > > > > from SG2 or from ASPs?
> > Depending on which he
> > > > > > > > > > might have to
> > > > > > > > > > > > > > > act as relay
> > > > > > > > > > > > > > > > > point or a normal SG?
> > > > > > > > > > > > > > > > [TOLGA] With the same method, it can
> > > > > > know, whether a
> > > > > > > > > > > > message is
> > > > > > > > > > > > > > > from ASP1
> > > > > > > > > > > > > > > or
> > > > > > > > > > > > > > > > ASP2, this is implemention dependent (but
> > > > > > > > most probably
> > > > > > > > > > > > > > based on the
> > > > > > > > > > > > > > > source
> > > > > > > > > > > > > > > > address of the SCTP message)
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > [Reshma] As per M3UA draft , m3ua
> > can act as an
> > > > > > > > > > SGP,ASP,IPSP.
> > > > > > > > > > > > > > > When it acts its an IPSP the peer is
> > > > always assumed
> > > > > > > > > > to be IPSP.
> > > > > > > > > > > > > > [TOLGA] No, IPSP will behaeve as ASP
> > against SGPs.
> > > > > > > > > > > > >
> > > > > > > > > > > > > This is not true. IPSP has a specific
> > behavior as
> > > > > > > > Reshma says.
> > > > > > > > > > > > > And if we consider SE even the State Machine
> > > > > > changes...  :-)
> > > > > > > > > > > > [TOLGA] I disagree with this. In my opinion,
> > > > IPSP needs to
> > > > > > > > > > > > behaeve as ASP
> > > > > > > > > > > > against SGPs.
> > > > > > > > > > >
> > > > > > > > > > > If you are handling received ASPUP or ASPAC, you
> > > > > > are not acting
> > > > > > > > > > > as an ASP. IPSP acts different to an ASP.
> > > > > > > > > > [TOLGA] This is what it does against another IPSP
> > > > (and still
> > > > > > > > > > there are so
> > > > > > > > > > many issues to discuss there). Well, maybe it
> > is better to
> > > > > > > > > > put ASPF+SGPF in
> > > > > > > > > > a box, so that ASPF can communicate with any
> > SGP without
> > > > > > > > problems ;-)
> > > > > > > > >
> > > > > > > > > If you read the mail I sent yesterday, you will
> > get all the
> > > > > > > > > problems this modelling arises...  ;-)
> > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Cheers // Javier.
> > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > > > And when it is SG it knows the peer
> > is ASP .And
> > > > > > > > hence there
> > > > > > > > > > > > > > was a set
> > > > > > > > > > > > > > > of messages defined in the draft
> > which they can
> > > > > > > > receive and
> > > > > > > > > > > > > > send for each
> > > > > > > > > > > > > > > one.
> > > > > > > > > > > > > > > But now we have SG-SG communication other
> > > > > > than SG-ASP
> > > > > > > > > > > > communication
> > > > > > > > > > > > > > > The initial behavior that SG should have is
> > > > > > > > > > different for SG-SG
> > > > > > > > > > > > > > > communication and SG-ASP
> > communication  ie SG
> > > > > > > > expects a SSNM
> > > > > > > > > > > > > > > followed by TAL
> > > > > > > > > > > > > > > meessage in SG-SG communication
> > whereas in case
> > > > > > > > of SG-ASP
> > > > > > > > > > > > > > has ASPUP and
> > > > > > > > > > > > > > > ASPAC procedures.So it should be configured
> > > > > > initially
> > > > > > > > > > > > > > ..which all ASPs and
> > > > > > > > > > > > > > > SGs will be connected and which peer is
> > > > an ASP/SG
> > > > > > > > > > ?(and behave
> > > > > > > > > > > > > > > differently?) OR SG should be
> > > > configured to either
> > > > > > > > > > behave as STP
> > > > > > > > > > > > > > > or as SEP?
> > > > > > > > > > > > > > [TOLGA] This is configuration.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Also once the TAL message is sent if
> > > > > > any PC is not
> > > > > > > > > > > > > > available then does
> > > > > > > > > > > > > > > one
> > > > > > > > > > > > > > > > > SG send DUNA to the other SG? How
> > > > it is handled?
> > > > > > > > > > > > > > > > [TOLGA] After TAL, if one PC becomes
> > > > available,
> > > > > > > > > > SG1 will send
> > > > > > > > > > > > > > > DAVA to SG2.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > [Reshma] But the draft says "4.3
> > Traffic Allowed
> > > > > > > > > > Message(TAL)
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >    TAL is used to indicate to a peer the
> > > > > > end of SSNM "
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Which is confusing
> > > > > > > > > > > > > > [TOLGA] The draft says "TAL is used
> > to indicate
> > > > > > > > to a peer the
> > > > > > > > > > > > > > end of SSNM ,
> > > > > > > > > > > > > > which are sent
> > > > > > > > > > > > > >    to declare list of not allowed/restricted
> > > > > > point codes,
> > > > > > > > > > > > after a SCTP
> > > > > > > > > > > > > >    association is established. ". I have the
> > > > > > > > impression, we
> > > > > > > > > > > > > > will change how
> > > > > > > > > > > > > > traffic is started and availability
> > information
> > > > > > > > is exchanged
> > > > > > > > > > > > > > but still to be
> > > > > > > > > > > > > > discussed.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > reshma
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
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