Re: Behaviour in DE-IPSP model when ASPAC does not have any RC.

Hello Brian,

Thanks for the reply -

i have a scenario - in the static configurations

one node has two AS's served by same ASP. on the peer node i have one AS
with an ASP.

if peer node sends ASPAC without RC. this will make remote AS state ACTIVE
and local AS's state also as ACTIVE in local stack. Though ASPAC_ACK would
have all the RC's of remote AS's which ASP is serving, in this case only
one. and remote stack would then mark its AS as ACTIVE and two AS's as
ACTIVE in its stack.

My question is what if out of two AS's only one AS at local stack is ready
to serve traffic? Remote stack in this case by default assumes, both AS's as
active.

According to 4.3.1 in RFC 4666, if single exchange behaviour is followed and
state machines are updated, we are not in a position to inform peer end
about our true capability to serve traffic.

IPSP
A
IPSP B
AS1
RC=100
AS1 RC=300
       ----------
ASP1
------------- ASP1
AS2  RC=200
       ---------- ASP1

   INIT
-------------------------------------------------------------------------------->


<-------------------------------------------------------------------------------
INIT_ACK
   COOKIE_ECHO
-------------------------------------------------------------------------------->

<-------------------------------------------------------------------------------
COOKIE_ACK

<-------------------------------------------------------------------------------
ASPUP
    ASPUP_ACK
-------------------------------------------------------------------------------->

<-------------------------------------------------------------------------------
ASPAC (without RC)
    ASPAC_ACK
--------------------------------------------------------------------------------->
(IPSP B will mark all the AS's as active in its stack, which are served
remote ASP, IPSP A also marks all remote AS's as active in local stack which
are served by remote ASP)




On 24 March 2010 21:11, Brian F. G. Bidulock <[email protected]> wrote:

> Anand,
>
> For each full duplex flow, DE requires one RC at one peer and another at
> the
> other peer.  This requires a double-ended exchange to activate using RC.
> Where the IPSP has a conifgured AS (see 4.3.4.3 second paragraph), no RC is
> required in ASPAC, in which case, the AS at each end is known by both sides
> and a single-ended exchage _could_ be possible.  That is all that it is
> saying.
>
> --brian
>
> Anand N Ilkal wrote:
>           (Wed, 24 Mar 2010 08:17:57)
> >
> >    Hello,
> >    In Double Exchange mode under IPSP-IPSP model. what should be the
> >    behaviour in case Remote Peer sends ASPAC without any Routing Context?
> >    Section 4.3.1 in RFC 4666 indicates the Single Exchange behaviour can
> >    be followed -
> >    extracts from RFC 4666 -
> >    "ASPTM messages. When sending ASPTM messages to activate/deactivate
> >    all the traffic independently of routing keys by not specifying any
> >    RC, a single exchange could be sufficient."
> >    Does it mean the local peer does not have to send ASPAC to the peer?
> >    Or is it just talking about multiple AS's in the remote peer? By
> >    sending only one ASPAC with no RC, it is updating the status for all
> >    the AS's in the remote peer which are served by the same ASP?
> >    --
> >    with regards,
> >    Anand kumar Ilkal
>
> > _______________________________________________
> > Sigtran mailing list
> > [email protected]
> > https://www.ietf.org/mailman/listinfo/sigtran
>
>
> --
> Brian F. G. Bidulock
> [email protected]
> http://www.openss7.org/
>



-- 
with regards,
Anand kumar Ilkal

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