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From: allan@cheers.cisco.com (Allan Leinwand)
Newsgroups: comp.dcom.sys.cisco
Subject: Re: X.25 over TCP/IP ?
Message-ID: <1991Mar21.205422.23450@csl.sri.com>
Date: 21 Mar 91 20:54:22 GMT
References: <1637@aut.autelca.ascom.ch>
Sender: news@csl.sri.com (NEWS Administrator)
Reply-To: allan@cheers.cisco.com (Allan Leinwand)
Distribution: comp
Organization: cisco Systems, Inc. - Menlo Park, CA
Lines: 72


In article <1637@aut.autelca.ascom.ch>, dhuber@aut.autelca.ascom.ch
(Daniel Huber) writes:
>Question:
>
>Is this possible:
>
>- HP9000/835 (HP-UX 7.0) with X.25
>- Route X.25 packets from HP, not over X.25 interface, but over TCP/IP
>  to a Cisco router
>- The Cisco router routes the X.25 packets from TCP/IP down to native
>  X.25 and into a public X.25 net...
>
>- The same backwards
>
>- If the scenario above works, is the Cisco router able to have
>  X.121 subaddresses ?
>
>
>      +---+		      +---+
>      |   | HP1		      |   | HP2
>      +-+-+		      +-+-+
>	|			|
>	| X.25 over TCP/IP	| X.25 over TCP/IP
>	|			|
>  ------+-------+---------------+--------- TCP/IP LAN
>		|
>		| X.25 over TCP/IP
>		|
>	      +-+-+
>	      |   |  Cisco
>	      +-+-+  
>		| <-- Subadressing for HP1 and HP2 possible?
>		|
>		|
>		| X.25
>		|
>  --------------+------------------ X.25 Network
>
>
>Thanks in advance for any responses...  :-)
>
>Daniel

Hello Daniel,

   First of all, to my knowledge HP does not allow for you to talk x.25
out of a LAN interface speaking Ethernet/802.3.  I do know of a x.25
serial interface for the HP9000 series.  If I am wrong, then HP must
have devised an encapsulation scheme for wrapping x.25 in a TCP/IP
packet.

   We here at cisco Systems do the same thing.  We wrap x.25 packets in
IP to provide connectivity through an IP network for x.25 nodes.  To do
this, we came up with our own undocumented encapsulation scheme.  If the
HP system used our encapsulation scheme then the cisco in your drawing
would think that HP1 and HP2 are other ciscos and route the packet just
like you want.  Unfortunately, this means you may have to rewrite the
applications or the drivers.  Not a pretty picture...

   The other suggestion I have for you to is to see if the applications
can use TCP/IP as a transport without x.25.  If this is possible, then
the cisco Protocol Translator (CPT) may help.  This device can translate
(not encapsulate) TCP/IP to x.25 and produce the results you desire.
Please contact us at cs@cisco.com or 1-800-553-NETS for more details on
the CPT.

Thanks,

Allan Leinwand
cisco Systems
leinwand@cisco.com