Hi folks,

I heard this very issue came up again in the PCE, after a couple of years.
Do you want me to finally put out a draft for this?

I think this is a basic change and requires a lot more then an errata, as
this changes the basic protocol functioning.

Thanks,
Vishwas

On Fri, Sep 11, 2009 at 10:01 AM, Vishwas Manral <[email protected]>wrote:

> Hi Adrian,
>
> It would have been ok if it was a connectionless transport like UDP.
>
> However I notice a problem when I want multiple sockets to use the
> same port number in particular cases. I figured that I cannot have a
> server socket (accepting connections) as well as a client socket
> trying to connect having the same port number, though I can allow same
> port to be shared across multiple sockets in some cases by using the
> socket option SO_REUSEPORT.
>
> Thanks,
> Vishwas
>
> On Fri, Sep 11, 2009 at 9:33 AM, Adrian Farrel <[email protected]>
> wrote:
> > Hi,
> >
> > For my part (I only worked as an author quite late in the process, but I
> was
> > helping to get this through the IESG review that raised issued about TCP
> > ports) I think Julien has not captured the point.
> >
> > The RFC is not silent about source ports because it does intend to limit
> the
> > scope.
> >
> > As Julien says, it does matter which port is listened on, and this is
> > deliberately a well-known port number so that it is not necessary to
> > configure (or advertise) the port that must be called.
> >
> > But in Section 4.2.1 you will find...
> >
> >  Only one PCEP session can exist between a pair of PCEP peers at any
> >  one time.  Only one TCP connection on the PCEP port can exist between
> >  a pair of PCEP peers at any one time.
> >
> > One way to help ensure this is to reduce the number of available ports to
> > use as the source port.
> >
> > Does restricting the source port cause any implementation or deployment
> > problems?
> >
> > Thanks,
> > Adrian
> >
> > ----- Original Message ----- From: <[email protected]>
> > To: <[email protected]>; <[email protected]>;
> > <[email protected]>
> > Cc: <[email protected]>
> > Sent: Thursday, September 10, 2009 9:57 AM
> > Subject: Re: [Pce] PCE port number
> >
> >
> > Hi Vishwas.
> >
> > Interesting comment. We must admit the wording is a bit ambiguous.
> >
> > RFC 5440 says: "The system listens to the PCEP-registered TCP port" and
> > "Upon receiving a TCP connection on the PCEP-registered TCP port"; I do
> not
> > see any behavior description for the source TCP port (good thing!).
> > My guess is that there is no intend to put constraints on the TCP
> initiator
> > port. I would interpret the sentence you mention as "using the registered
> > TCP port on the PCE side, i.e. for the source TCP port for PCE to PCC
> > messages and for destination TCP port for PCC to PCE messages"... A
> little
> > cumbersome, I agree.
> >
> > Authors of RFC 5440, would there be an actual intend to specify
> otherwise?
> > Implementers, any other interpretation?
> >
> > Thanks,
> >
> > Julien
> >
> >
> > -----Original Message-----
> > From: [email protected] [mailto:[email protected]] On Behalf Of
> > Vishwas Manral
> >
> > Hi,
> >
> > I looked at the following in the spec:
> >
> > “Transport Protocol
> >
> >  PCEP operates over TCP using a registered TCP port (4189).  This
> >  allows the requirements of reliable messaging and flow control to be
> >  met without further protocol work.  All PCEP messages MUST be sent
> >  using the registered TCP port for the source and destination TCP
> >  port.”
> >
> > This has been worrying me a bit. Unlike other protocols like BGP or LDP
> >
> > In BGP it states clearly:
> >
> >  A BGP implementation MUST connect to and listen on TCP port 179 for
> >  incoming connections in addition to trying to connect to peers.
> >
> > and
> >
> >  BGP's destination port SHOULD be port 179, as defined by IANA.
> >
> > Why do we have this restriction on source port? It is becoming a
> > challenging task
> > in merchant OS.
> >
> > Thanks,
> > Vishwas
> > Vishwas
>
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