[Pce] PCE port number

[Vishwas Manral <vishwas.ietf at gmail.com>]

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