Re: Fact or fiction

Alan R. Hill (
Fri, 27 Mar 87 10:56:11 EST

        I'll take a crack at answering your knowledgable inquiries.

Basic X.25 allows multiple VCs between a given host pair. Each VC gets its
own connection at level 3. X.25 traffic is encapslated in 1822 and delivered
to the subnet. The traffic is subject to 1822 restrictions. All traffic
between host pairs is on one dynamic subnet connection. X.25 acts like
a software host so 1822 delivers the encapslated data to X.25 which handles
the L3 connection control.

Your understanding of Standard X.25 is correct. The answer to your question
is Yes.

        IOP strives to do the reasonable thing about hardware padding on
messages. BBN believes that there was a problem during the early days
of IOP but the software has been corrected. If this is not the case I
hope people will speak up and let us know.

        PSN 7.0 will make significant changes in the way X.25 traffic
is handled as well as major modifications to the subnet E-E. X.25 and
AHIP (1822) will be handled as peer protocols thus elimnating the
need for IOP and significantly improving X.25 performance. RFC978 might
help you understand some of the features of PSN 7.0.


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