RE: SNA over IP

[pytel@xxxxxxxxxx]

There are two misconceptions here, which I often see and decided to comment
on.
First, SNA is not more chatty than TCP/IP.
If you will look at communications trace, SNA will deliver approximately
the same amount of payload per same amount of LAN frames. SNA RUs do have
longer headers than TCP/IP packets but the difference is insignificant.
Second, while MPTN (aka ANYNET) certainly adds an overhead and slows things
down, it is not encapsulation per se.
MPTN uses different technique.

It's true, that SNA requires more careful configuration - there are very
few things you can actually configure in TCP/IP, which makes it easier to
use. Non-optimal configuration can lead to excessive traffic and IOP
utilization - which can explain your experience.

    Alexei Pytel



Chris Bipes <chris.bipes@cross-check.com>@midrange.com on 10/04/2000
10:47:04 AM

Please respond to MIDRANGE-L@midrange.com

Sent by:  owner-midrange-l@midrange.com


To:   "'MIDRANGE-L@midrange.com'" <MIDRANGE-L@midrange.com>
cc:
Subject:  RE: SNA over IP



SNA is very chatty.  It will add to your network utilization.  Also
encapsulation any protocol over another adds over head.  Thus the IOP
processors have more work to do.  If you are a very heavy user of the SNA,
it will effect performance.  I have 3 as400s all running ANYNET and it is
fast on the 170 and 720.  They both have PCI 10/100 Ethernet cards, with
the
720 having two.  The model 400 running an older SPD IPCS card at 10mb had a
noticeable slow down.  The change does not effect straight TCP/IP, just the
IOP.  If the IOP is overloaded, then you will notice a slow down of
straight
TCP/IP.  We have not had any problems on either of the boxes with ANYNET.
When IBM gets all the neat SNA function re-written to TCP/IP you will not
need ANYNET, but till then...  Tell me why do you need Anynet turned on?
What is the application?

HTH,



Christopher K. Bipes     mailto:ChrisB@Cross-Check.com
Sr. Programmer/Analyst   mailto:Chris_Bipes@Yahoo.com
CrossCheck, Inc.         http://www.cross-check.com
6119 State Farm Drive    Phone: 707 586-0551 x 1102
Rohnert Park CA  94928   Fax: 707 586-1884

If consistency is the hobgoblin of little minds, only geniuses work here.
Karen Herbelin - Readers Digest 3/2000

-----Original Message-----
From: Jim Knight [mailto:jknight@rei.com]
Sent: Wednesday, October 04, 2000 8:14 AM
To: 'Midrange Users list'
Subject: SNA over IP


We are looking at utilizing APPC over IP via ANYNET.  We have several
processes that use IP sockets
to look up data from our RS/6000s.  I read in the Communications
Configuration Manual that by
activating ANYNET, our sockets programs will run slower.  This is the V4R1
manual.  Is this still
true on V4R4??
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