Sun Microsystems SunLink SNA 9.1 PU2.1, Configuration Manual

Page: 248 / 298

C-14 SunLink SNA 9.1 PU2.1 Server Configuration Guide—August 1997
C
•
Whether parallel sessions are supported between the LUType 6.2s. Parallel
sessions allow the LU-LU pair to support more than one active session of the
same mode at the same time. Parallel sessions allow optimal use of the LU-LU
pair, enabling multiple transactions of the same type to proceed concurrently.
An installation normally designates some of the defined sessions as auto-
activated sessions. These sessions are automatically activated whenever the
local LUType 6.2 is started or reset. This establishes a free pool of sessions,
avoiding the session activation overhead whenever a conversation requests
a session.
•
The maximum number of active sessions of the mode that can exist between
the two LUType 6.2s. If this number is greater than 1, parallel sessions must
be supported.
•
The polarity of the sessions. The session polarity determines which LUType
6.2 wins if both LUs simultaneously attempt to activate a particular session.
When the session is a contention winner (or first speaker), the local LU
always wins when there is contention. When the session is a contention
loser (or bidder), the partner LU always wins and the contention-loser
LUType 6.2 bids the contention-winner LUType 6.2 to use the session. The
mode defines the minimum number of contention-winner sessions and
contention-loser sessions available. Session limits and session polarities can
be changed using Change Number of Sessions (CNOS) verbs.
C.5.4 Independent or Dependent LUType 6.2s
An LUType 6.2 can be independent or dependent. An independent LUType 6.2
can communicate directly with a peer system over multiple parallel sessions. A
dependent LUType 6.2 is owned by a local PU type 2 (and has a configured
LOCADDR) and requires the support of a host (SSCP) to establish a single
session with a remote LUType 6.2.