Subject: somewhat related timer discussion with geoplex

From: [email-masked]
Date: Sun, 21 Nov 1999 16:02:20 -0800

From: Anne & Lynn Wheeler <[email-masked]>
Subject: Re: GEOPLEX
Newsgroups: bit.listserv.ibm-main,alt.folklore.computers
Date: Sun, 21 Nov 1999 21:07:03 GMT
Reply-To: Anne & Lynn Wheeler <[email-masked]>
Organization: Wheeler&Wheeler

long ago & far away we had that problem with JES2 link between STL and
Hursley being switched from a land-line to a double-hop satellite
link. They brought up JES2 pair on the link and couldn't establish a
connection ...so they stopped and brought up VNET on the link and
everything would transfer fine w/o any errors. They dropped the link
and brought up pair of JES2 again and were unable to establish a
connection. Somebody's conclusion was that the line was full of errors
and VNET was just too stupid to realize it (of course the problem was
that JES2 had a keep-alive ping that had time-out shorter than the
satellite double-hop round trip).

misc. references (including hardware FEC for reliable transmission,
also frequently used in many satellite systems):

http://www.garlic.com/~lynn/99.html#210

http://www.garlic.com/~lynn/96.html#15
http://www.garlic.com/~lynn/99.html#33
http://www.garlic.com/~lynn/99.html#71
http://www.garlic.com/~lynn/99.html#77
http://www.garlic.com/~lynn/99.html#91
http://www.garlic.com/~lynn/99.html#110
http://www.garlic.com/~lynn/99.html#145
http://www.garlic.com/~lynn/99.html#184
http://www.garlic.com/~lynn/99.html#209

[email-masked] writes:

> >Can I have a GEOPLEX player several thousand miles away and have
> >a minimum of 1 structure list i.e. logger?
>
> No.  No can do.
>
> There is a finite limit to the distance allowed for the communication
> protocols used for the Sysplex Timer and Coupling Facility, which is the
> limiting factor to a Geographically dispersed Sysplex.
> Greg
>
> Greg Dyck
> IBM Poughkeepsie, OS/390 BCP Platform team

--
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Anne & Lynn Wheeler   | [email-masked], [email-masked]
 http://www.garlic.com/~lynn/ http://www.adcomsys.net/lynn/