Subject: [pilc] interoperability issue with TCP PEP

From: "Lakshmi Priya" <[email-masked]>
Date: Wed, 28 Jul 2004 17:12:02 +0530

hi,

     Would it be possible to implement PEP such that it is interoperable
with other PEP implementations?
That is, in a split connection, is it possible to have 2 different vendor
implementations running on either end of satellite link PEP nodes? Are there
any such implementations?

     Since there are no standards to the way in which the end host
information is carried over the satlink after spoofing, I guess this would
not be possible. There could also exist many other proprietary control
packets. Any inputs in this regard is welcome.

thanks and regards,
Lakshmi Priya

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---

From: "Keith L. Scott" <[email-masked]>
Date: Wed, 28 Jul 2004 11:44:22 -0400

Lakshmi,

It is entirely possible for PEPs made by different vendors to interoperate,
provided the vendors implement a common standard; and yes, there _is_ a
standard for how the information is carried across the satellite link.

The Space Communications Protocol Standards: Transport Protocol (SCPS-TP,
also sometimes referred to as TCP tranquility) defines a set of TCP options
that can improve TCP performance in stressed environments, including
satellite communications.  PEP products that implement these options are
available from a number of vendors, and should interoperate if they all
conform to the specification.  There is also a freely available reference
implementation of the SCPS protocols that includes a PEP application that is
available by sending mail to the point of contact listed at
http://www.scps.org.

Tranquility is completely backward-compatible with other TCP
implementations; all of the Tranquility-specific functionality is negotiated
during the SYN exchange.  By using different settings for the terrestrial
and satcom sides of the PEPs, they can dramatically improve performance over
the satcom link.  There is currently no implementation that I know of that
does private, out-of-band signaling between the PEPs, though I can envision
uses for such signaling.

I'd be happy to answer any other questions you have or to point you at some
vendors.

The SCPS-TP protocol spec is available from
http://www.ccsds.org/CCSDS/documents/714x0b1.pdf

Best regards,

		--keith

>-----Original Message-----
>From: [email-masked] [mailto:[email-masked]] On 
>Behalf Of Lakshmi Priya
>Sent: Wednesday, July 28, 2004 7:42 AM
>To: [email-masked]
>Subject: [pilc] interoperability issue with TCP PEP
>
>
>hi,
>