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PBURST.TXT
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1994-06-15
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NOVELL TECHNICAL INFORMATION DOCUMENT
TITLE: Packet Burst files for Wide Area Networks
DOCUMENT ID: TID014298
DOCUMENT REVISION: C
DATE: 14JUN94
ALERT STATUS: Yellow
INFORMATION TYPE: Symptom Solution
README FOR: PBURST.EXE
NOVELL PRODUCT and VERSION:
NetWare 3.11
NetWare 3.12
NetWare 4.01
ABSTRACT:
PBURST.EXE has packet burst files that implement a new packet burst algorithm
for WAN links to fix problems where 1) burst retries could saturate WAN links
due to low retry timeout values 2) workstations hang when duplicate packets
from a previous burst are received in the middle of the current burst.
PBURST.NLM is for use on NetWare 3.11 file servers. PBWANFIX.NLM (which
requires patchman) is for use on NetWare 3.12 and 4.01 file servers. To allow
the new packet burst algorithm to work, these files must be used with FIO.VLM
from VLMUP2.EXE and the v1.10 VLMs from DOSUPx.EXE.
------------------------------------------------------------------------------
DISCLAIMER
THE ORIGIN OF THIS INFORMATION MAY BE INTERNAL OR EXTERNAL TO NOVELL. NOVELL
MAKES EVERY EFFORT WITHIN ITS MEANS TO VERIFY THIS INFORMATION. HOWEVER, THE
INFORMATION PROVIDED IN THIS DOCUMENT IS FOR YOUR INFORMATION ONLY. NOVELL
MAKES NO EXPLICIT OR IMPLIED CLAIMS TO THE VALIDITY OF THIS INFORMATION.
------------------------------------------------------------------------------
SYMPTOM
Saturation of WAN links with burst retries. Disabling packet burst increases
throughput over a WAN link.
SYMPTOM
Workstations hang when packet burst is enabled, but work fine when packet
burst is disabled.
CAUSE
Due to a low retry timeout value over some WAN links, several burst retries
could be sent without allowing enough time for the first burst reply.
SOLUTION
Apply PBURST.EXE.
Self-Extracting File Name: PBURST.EXE Revision: C
Files Included Size Date Time
\
PBURST.TXT (This File)
PBURST.NLM 95956 04-05-94 1:30p
APPNOTE.TXT 32917 11-16-93 2:19p
\PBWANFIX.312\
PM312.DOC 3695 06-09-94 8:32a
PM312.NLM 9221 03-24-94 11:06a
PBWANFIX.NLM 3028 04-19-94 9:41a
\PBWANFIX.401\
PM401.DOC 3684 06-09-94 8:47a
PM401.NLM 8113 02-03-94 1:09a
PBWANFIX.NLM 2523 04-19-94 9:44a
Installation Instructions:
Extracting this file will cause a PBWANFIX.312 and a PBWANFIX.401 directory
and associated files to be created.
For a file server NetWare 3.11 operating system:
1) Copy PBURST.NLM to the SYS:SYSTEM directory, or the local drive on the
file server.
2) At the console, type LOAD PBURST.
3) To ensure that Packet Burst is loaded each time the server is rebooted,
add LOAD PBURST.NLM to the file server's AUTOEXEC.NCF.
For a file server NetWare 3.12 operating system:
1) Copy PM312.NLM and PBWANFIX.NLM from the PBWANFIX.312 directory in this
zip file, to the SYS:SYSTEM directory, or the local drive on the file server.
2) At the console, first type LOAD PM312.
3) At the console, type LOAD PBWANFIX.
4) To ensure that Packet Burst is loaded each time the server is rebooted,
add LOAD PM312 and LOAD PBWANFIX to the file server's autoexec.ncf.
For a file server NetWare 4.01 operating system:
1) Copy PM401.NLM and PBWANFIX.NLM from the PBWANFIX.401 directory in this
zip file, to the SYS:SYSTEM directory, or the local drive on the file server.
2) At the console, first type LOAD PM401.
3) At the console, type LOAD PBWANFIX.
4) To ensure that Packet Burst is loaded each time the server is rebooted,
add LOAD PM401 and LOAD PBWANFIX to the file server's AUTOEXEC.NCF.
GENERAL INSTALL INFORMATION FOR PATCHMAN/PATCHES:
Dynamic patches are loaded at the file server console as NetWare Loadable
Modules and require PM401.NLM or PM312.NLM to be loaded.
To ensure that the patch is always in effect when the server is initially
brought up, placing the command "LOAD <patch name>" in the server's
AUTOEXEC.NCF file is recommended.
Because these are NLMs, the patches can be loaded and unloaded without ever
having to bring the server down. After they are loaded, the operating system
is patched and ready to go.
Unloading the patches will restore the operating system to its original
"unpatched" state.
Installation:
To install a specific patch or patches, simply place the patch file in the
same directory as the other NLM files (SYS:SYSTEM or DOS partition), and type
"LOAD <patch name>" for each patch you wish to load.
After a patch has loaded, all changes are in effect until it is unloaded. If
an error message appears, contact Novell Technical Support.
As previously suggested, you will probably want to enter the LOAD commands
into your AUTOEXEC.NCF file to insure that the patches are loaded
automatically.
Solution Specifics:
Short timeouts don't work well over WAN links. The server doesn't have a good
idea of the transport time. The new packet burst files will prevent the
server from asking for data from a write request that is currently in transit
from the client.
When duplicate read requests are received, the new packet burst files will
only reply with a short piece of data, rather than replying with the whole
burst. This prevents unnecessary duplicate bursts from being sent when
duplicate read requests are sent while the burst read reply is in transit. It
also forces the client to request the missing packets from a burst read reply
if any packets in the burst were dropped. This guarantees that all the data
will be transferred without flooding the WAN with duplicate bursts.
Rather than having a moving timeout algorithm, timeouts are now based off the
initial round trip time calculated at connect time. If the LIP echo socket is
not supported on a server (that is, 2.x NetWare, or 3.11 without PBURST
loaded), a default of (MLID transport time * 4 + 10) ticks is used.
Workstations connected to WANs may override this with a NET.CFG command
"MINIMUM TIME TO NET". This is needed for bridged WAN/Satellite
configurations where the time-to-net we get from the router is much too low.
This NET.CFG parameter must be used in these configurations when the server on
the other side of the link is NetWare 2.x or NetWare 3.11 (without PBURST.NLM
loaded) because these servers don't support the echo socket that NetWare uses
to measure the actual time to net. This parameter may also be needed when
using a link of 2400 baud or less. The parameter value is in milliseconds (a
value of 1000 = 1 sec).
ASSOCIATED NET.CFG PARAMETERS FOR THIS VERSION OF VLMs:
PB BUFFERS = n (0-10) default=3
Note: 0 is disabled, non-zero is enabled. See APPNOTE.TXT pages 6 and 7
for an explanation of the changes to this parameter, and influence this
parameter has on performance/memory.
PBURST READ WINDOW SIZE = n (3-255) default=16
Note: See "Window Size in the VLMs" pages 8-10 in APPNOTE.TXT for an
explanation of this parameter.
PBURST WRITE WINDOW SIZE = n (3-255) default=10
Note: See "Window Size in the VLMs" pages 8-10 in APPNOTE.TXT for an
explanation of this parameter.
MINIMUM TIME TO NET = n (0-65535)
Overrides the "time-to-net" value defined by the local router during
connection time. This parameter is used for bridged WAN/Satellite links with
"time-to-net" values set to low for workstations under the following
conditions to make a connection:
1. The server on the other side of the link is a non-pburst 3.x or below
server.
2. The transfer rate for the link is 2400 baud or less.
Note: The value is set in milliseconds. i.e. MINIMUM TIME TO NET = 10000
would set the value to 10 seconds.
If the workstation cannot make an initial connection, try increasing this
parameter. In a packet bursting environment, the value will adjust back down
after the initial connection, to a more optimal value. HOWEVER, if the
workstation connects to a non-bursting server, this value stays at the value
set in the NET.CFG. If this value is artificially high, it may adversely
affect performance.
GENERAL
The December 1993 "NetWare Application Notes" has an article covering VSAT
(Very Small Aperture Terminal) and satellite delay influences on packet burst.
X_Verified by customer
X_Verified by Novell
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