1999/12/21 ComOS 3.8.2c4 Interim Release Note _______________ Introduction The Lucent Remote Access ComOS(R) 3.8.2c4 interim software release for the PortMaster(R) 3 Integrated Access Server is now available. Note that a ComOS 3.8.2c3 version was not publicly released. This release is provided at no charge to all Lucent customers. This release note applies only to the PortMaster 3 and documents updates to the modem code. All other features are identical to those in ComOS 3.8.2. NOTE: This interim software release is recommended only for customers who are experiencing the problems described and are unable to wait for the next maintenance release. Before upgrading, thoroughly read "Limitations" and "Upgrade Instructions." _______________ Contents Introduction Modem Bugs Fixed in ComOS 3.8.2c4 ComOS 3.8.2c4 Limitations Troubleshooting Modems Upgrade Instructions Technical Support _______________Modem Bugs Fixed in ComOS 3.8.2c4 The following modem bugs are fixed in ComOS 3.8.2c4. ________Code Fixed for Sega Dreamcast Game New modem code for the Sega Dreamcast video game modem has been implemented. As a result, the PortMaster switches to buffered mode more quickly -- after 10 seconds rather than after 40 seconds. This quicker mode change allows the PortMaster to conduct Link Access Procedure for Modems (LAPM) negotiation and detect open distributed processing (ODP) failures if it receives an exchange identification (XID) within 10 seconds. Otherwise, the PortMaster uses the Microcom Networking Protocol (MNP) or buffered code. ________V.8 Logic Improvements V.8 modem negotiation logic has been modified to check for the V.90 or V.34 data rate before falling back to V.32. Previously, some modems completed V.8 negotiation and falsely triggered the PortMaster to use V.32. By checking for V.90 or V.34 first, the PortMaster now ensures that only V.32 modems connect at V.32 rates. ________V.8bis Logic Improvements V.8bis logic has been improved to force PCTEL modems to V.90. PCTEL modems do not set the V.90 bit during V.8bis negotiations, but set a proprietary bit instead. If the PortMaster detects that this proprietary bit is set on a PCTEL client modem, it uses V.90 rates. One drawback is that a PCTEL modem set for K56flex will fail V.90 and fall back to V.34. ________K56flex Improvements K56flex code has been improved to better handle rate renegotiations with Rockwell client modems. ________LAPM Suspension during Rate Changes and Retrains To reduce the number of disconnections, the PortMaster now suspends all LAPM negotiations and data transfers during rate changes and retrains, and also resets timers. The Link Access Procedure for Modems (LAPM) is the final and highest-layer phase of V.90 modem negotiation that occurs during the process of connecting to a communications server: 1. Packets received from the OSI data link layer of the transmitting device traverse the LAPM layer during modem V.90 negotiation and undergo compression and error control. 2. Once the packets are compressed, they are transferred down through the V.90 layers to the physical transport layer and received by the modem on the other end. 3. The receiving modem then passes the packets back up to the V.90 layer of LAPM on the receiving device. 4. The LAPM layer checks the packet header for errors and decompresses the packet data before passing the packet to the OSI data link layer of the receiving device. Packet transmission rate is determined at the lower V.90 layers. Because no packets can be transferred from a higher layer while the lower layers are busy determining the speed of transfers, the PortMaster suspends LAPM activity during this time. ________LAPM Selective Reject Support The PortMaster now supports selective reject to improve throughput for modem clients that support this feature. Selective reject is an important throughput adjustment that allows modems to retransmit only frames that arrive with an error, to conserve precious bandwidth and time. For example, suppose that the PortMaster and a client modem agree on a window size of five frames. The first frame from the client arrives correctly, the second frame arrives in error, and subsequent frames arrive without error. Modems without selective reject (most modems) will retransmit frames 2 through 5, but a modem with selective reject retransmits only frame 2 and then continues on to transmit frame 6 and subsequent frames. The PortMaster now supports this feature. ________Line Improvements Poor upstream connections, NO EC (no error control), and No Connect problems on lines with more than one analog-to-digital conversion and other lines that do not support V.90 have been fixed. ________A-Law V.90 Transmission Increase Maximum digital modem transmission for A-law V.90 has been increased to -9dBm from -12dBm, to reduce the rate changes for A-law modem clients in Europe. ________Loss-of-Carrier Detection Improvement Modems now detect loss of carrier for V.90 calls over T1 lines with foreign exchange station (FXS) or foreign exchange office (FXO) interfaces (Loop Start Lines). ________Timeout Errors Fixed The PortMaster now informs certain modem clients of the proper LAPM window size to use, fixing some LAPM timeout errors that occurred in previous releases. Window size determines how many packets are sent before the other LAPM partner can report that it received the bits and frames sent correctly. The two modems must agree on this number. Sending a single frame of 128 bytes to the client and waiting for the client to acknowledge is less efficient than sending multiple frames and waiting for a single acknowledgement. For example, suppose the PortMaster is set for a window size of three frames and the remote device expects a window size of four. When the PortMaster sends three frames and waits, the remote modem waits for a fourth frame before acknowledging. Disagreement about window size can cause timer expiration or even disconnection. This problem has now been corrected for certain clients. _______________ ComOS 3.8.2c4 Limitations * Support for the obsolete "True Digital V.34 Card" (MDM-PM3-8 and MDM-PM3-10) has been removed from this release, except for support of the V.110 protocol. The "True Digital 56K Card" (MDM-56K-8 and MDM-56K-10) is still supported. * Lucent is still fixing some problems with Rockwell HCF and Cirrus Logic modems. If you experience any difficulties with modems, verify that the client modem is running the latest firmware. Then refer to http://www.livingston.com/tech/bulletin/comos-modem.html. If these instructions do not help, contact Lucent NetCare(R) technical support. * A PCTEL modem set for K56flex in its proprietary bit will be incorrectly identified as being set for V.90 by the PortMaster. As a result, the modem will fail V.90 negotiations with the PortMaster and will fall back to V.34 rates. _______________ Troubleshooting Modems As part of modem troubleshooting, confirm that the client modem is running the latest firmware before submitting a modem trouble report. When making a report of a new modem problem, send the following information to Lucent NetCare technical support: * ComOS version * Client modem manufacturer * Client modem model * Results on the client modem of commands ATI0 through ATI11 * Whether the problem is reproducible Lucent might want to monitor your PortMaster while the client modem reproduces the problem. _______________ Upgrade Instructions You can upgrade your PortMaster 3 using PMVision 1.8 or later, or pmupgrade 4.3 or later from PMTools. Alternatively, you can upgrade using the older programs pminstall 3.5.3, PMconsole 3.5.3, or PMconsole for Windows 3.5.1.4. You can also upgrade using TFTP with the "tftp get comos" command from the PortMaster command line interface. See ftp://ftp.livingston.com/pub/le/software/java/pmvision18.txt for installation instructions for PMVision 1.8. *** CAUTION! If the upgrade fails, do NOT reboot! Contact *** Lucent NetCare Technical Support without rebooting. The upgrade process on the PortMaster 3 erases the configuration area from nonvolatile memory and saves the current configuration into nonvolatile memory. Never interrupt the upgrade process, or loss of configuration information can result. This upgrade does not otherwise affect your stored configuration in the PortMaster. The installation software can be retrieved by FTP from ftp://ftp.livingston.com/pub/le/software/, and the upgrade image can be found at ftp://ftp.livingston.com/pub/le/upgrades: ComOS Upgrade Image Product _________ _____________ _____________________________________ 3.8.2c4 pm3_3.8.2c4 PortMaster 3 ________________________________________________________________________ Copyright and Trademarks Copyright 1999 Lucent Technologies. All rights reserved. PortMaster, ComOS, ChoiceNet, and NetCare are registered trademarks of Lucent Technologies. PMVision, IRX, PortAuthority, and NavisRadius are trademarks of Lucent Technologies. All other marks are the property of their respective owners. Notices Lucent Technologies makes no representations or warranties with respect to the contents or use of this publication, and specifically disclaims any express or implied warranties of merchantability or fitness for any particular purpose. Further, Lucent Technologies 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 Lucent NetCare Technical Support Lucent NetCare Professional Services provides PortMaster technical support via voice or electronic mail, or through the World Wide Web at http://www.livingston.com/. Specify that you are running ComOS 3.8.2c4 when reporting problems with this release. Internet service providers (ISPs) and other end users in Europe, the Middle East, Africa, India, and Pakistan should contact their authorized Lucent NetCare sales channel partner for technical support; see http://www.livingston.com/International/EMEA/distributors.html. For North America, the Caribbean and Latin America (CALA), and Asia Pacific customers, technical support is available Monday through Friday from 7 a.m. to 5 p.m. U.S. Pacific Time (GMT -8). Dial 1-800-458-9966 within the United States (including Alaska and Hawaii), Canada, and CALA, or 1-925-737-2100 from elsewhere, for voice support. For email support, send to support@livingston.com (asia-support@livingston.com for Asia Pacific customers).