Version 2.3 of ImageStream's Enterprise Linux is now available as a
general release for all ImageStream router customers.  Version 2.3 will be
the final release in the Version 2 series.

This software release is provided at no charge to all ImageStream
customers, and is recommended for all customers who wish to upgrade to the
latest available software release.

This release note documents commands and features added between Version
2.2.3 and Version 2.3.

----------------------------

New Features in Version 2.3


Rate limiting

Enterprise Linux Version 2.3 supports rate limiting on an
interface-by-interface basis.  Previously, ImageStream routers could only
be used for IP/network-based filters using Linux's standard diffserv
package.  The new "rate-limit" interface commands allows rate-limiting
policies on packets sent and received on a particular interface.  The
"rate-limit" commands also allows for configurability of latency and
buffering, affecting packet drop rates.  This SAND feature is available
only on ImageStream routers.


Frame Relay Sub-Interfaces Now Use Hash Tables

The SAND frame relay protocol module now uses has tables to maintain lists
of frame relay sub-interfaces.  In prior versions, a linked list was used.
The hash table lookups will reduce the CPU overhead and processing time
required to handle data for a sub-interface, especially on systems with
large numbers of frame relay sub-interfaces.


Improved Data Handling On All Cards

The SAND architecture now pre-allocates buffers for data sent and received
on WAN interfaces.  Previously, an extra layer of memory copies was
required to process data.  This additional copy caused inefficient use of
the router's Level 2 cache and introduced additional processing time in
each transmit or receive operation.  The buffer allocation method used in
Version 2.3 should increase available CPU and decrease latency, especially
on high-traffic systems.


Improved Interrupt Handling On WANic/Aries 600 And 800 Series Cards

The WANic and Aries 600 (604, 608, 654, 658) and 800 (800, 805, 850, 855)
series cards support an improved level of interrupt handling.
ImageStream's SAND drivers now signal the 600 and 800 series cards to
generate fewer interrupts per packet in high-traffic systems.  The drivers
automatically scale from 1 packet per interrupt to 16 packets per
interrupt.  This change dramatically reduces the number of interrupts per
second on a heavily-loaded system, and will result in lower CPU
utilization and better router response in these environments.


----------------------------


Bugs fixed in Version 2.3


The following bugs have been fixed on all ImageStream routers in Version
2.3:


E3 Aliases Have Been Added

All "service-module e3" commands should now be recognized in the main
configuration file (wan.conf).  Previously, not all E3 commands were
correctly processed.


Byte Count On HDLC Keepalives Corrected

In prior versions, the SAND HDLC protocol module incorrectly calculated
the size of HDLC keepalive packets.  This internal calculation error did
not affect the operation of HDLC links, but created output in hardware
debug messages that could appear erroneous.


----------------------------


Upgrade Instructions


*** NOTE! If the upgrade fails, do NOT reboot! Contact ImageStream's
Technical Support without rebooting. *** 

The upgrade process on an ImageStream router erases the operating system
software area from nonvolatile memory. Never interrupt the upgrade
process, or loss of software information can result. 

The upgrade does not otherwise affect the stored configuration in the
ImageStream router. To back up the router's configuration prior to
upgrading, choose option 4 (Backup/Restore) from the router's main menu.
Choose the Backup methods option (Option 1) and select a method from the
choices listed.  From the router's command line, use the "backup
<typeofbackup>" command. The backup utility takes four arguments: flash
(to back up configurations to the router's nonvolatile flash memory),
floppy (to back up to a floppy disk), scp (to back up via secure copy), or
file (to back up to a separate file on the router's nonvolatile flash
memory).



----------------------------


Copyright and Trademarks


Copyright 2001 ImageStream Internet Solutions. All rights reserved. 

ImageStream is a trademarks of ImageStream Internet Solutions, Inc.  All
other marks are the property of their respective owners. 

Notices 

ImageStream makes no representations or warranties with respect to the
contents or use of this document, and specifically disclaims any express
or implied warranties of merchantability or fitness for any particular
purpose. Further, ImageStream reserves the right to revise this
publication and to make changes to its content, any time, without
obligation to notify any person or entity of such revisions or changes. 

Contacting ImageStream Technical Support 

Every ImageStream product comes with a one year hardware and software
warranty. ImageStream provides technical support via voice, FAX,
electronic mail, and the web. Technical support is available 24 hours a
day, 7 days a week.

To contact ImageStream technical support by voice, dial +1 (219) 935-8484
worldwide. By FAX, dial +1 (219) 935-8488. By electronic mail, send mail
to support@imagestream.com. Using the World Wide Web, see
http://www.imagestream.com/


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