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 > _______________________________________________ > Pce mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/pce > _______________________________________________ > Pce mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/pce > > _______________________________________________ Pce mailing list [email protected] https://www.ietf.org/mailman/listinfo/pce
