LANtastic by ARTISOFT Artisoft Technical Bulletin TITLE: Central Station Connectivity Processor FILENAME: CS.TXT UPDATED: 04.27.95 CLASSIFICATION: Network media AUTHOR: POH Overview The Central Station and Central Station II Connectivity Processors are designed as multi-function network access devices. They serve three different purposes. Both units utilize a V40 processor to handle multiple tasks simultaneously. Both units have 10BaseT and BNC ethernet connectors, a PC port (parallel), an LPT1 port, two COM ports (serial), and an Auxiliary port (serial). The PC port and AUX port may be used for printing on the Central Station II. Laptop to Ethernet (LTE): Allows a computer to access the LAN via the parallel port of the computer. This is convenient for computers which cannot accommodate an internal network adapter or PCMCIA card. The LPT1 port on the Central Station acts as a pass-through parallel port, so the computer does not lose it's printing capability when connected to the Central Station. LANtastic or Netware Printer Server (LPS/NPS): Allows networked computers to redirect their print jobs from the computer's printer ports to printers attached to the Central Station. The Central Station can print to one parallel printer and two serial printers. The Central Station II can print to two parallel printers, and three serial printers. This is convenient when installing printers in a central location without the need to have a Netware Print Server or a PC dedicated to handle those printers. Spooled print jobs do need to be handled by a PC, as even though the name implies that Central Station is a print server, it does not have any capabilities for spooling print jobs. Using the Central Station to handle the actual printing function also alleviates the server from performing that task, letting the server operate more efficiently. Print jobs should be spooled on a server, because if a workstation redirects a print job directly to a Central Station and the printer is being used, the workstation will return the error "Write fault writing device LPT1. Abort, Rerty, Fail ?", as if there is a problem with the printer. LANtastic or Netware Dial-Up (LDU/NDU): Allows remote computers to dial into a LAN and access network servers via analog modem connections. Two modem connections can be maintained simultaneously on the COM1 and/or COM2 ports of Central Station. The AUX port does not support modem usage. The remote computers run the network operating system, using the modem as their NIC, and login to servers just as any other node on the network. Speed is a major concern when using remote dial-up services, as analog modem connections are inherently slow. Speed issues are addressed later in this document. All three functions are supported for simultaneous operation in any combination of configurations, in a LANtastic LAN or in a Netware LAN. This allows for greater flexibility when configuring the Central Station to best serve your network connectivity needs, and eliminates the need for multiple devices to perform all three functions. These functions are installed to the ROM of the Central Station through the Stationware software. Each function is a separate software module, which may be installed or removed from the Central Station's ROM, using the CSCONFIG program. Stationware Versions: To date, there have been four versions of Stationware; v1.0, v2.0, v2.1, & v3.0. While the Central Station can use any version of the Stationware, a Central Station II can ONLY use v3.0 Stationware. Below is a chart showing which versions are needed for each version of LANtastic: Central Station Central Station II Stationware version Stationware version LANtastic v4.0 1.0 N/A LANtastic v4.10 1.0 or 2.0 N/A LANtastic v5.0 2.1 or 3.0 3.0 LANtastic v6.0 3.0 3.0 When configuring the Stationware in a Central Station with the CSCONFIG program, all software modules must be the appropriate versions. Below is a chart of the Stationware module versions for each Stationware version. Note that Stationware v1.0 is not included here, as we strongly recommend upgrading anyone using Stationware v1.0. Station Ware LTE LPS LDU NETDRV CSPPORT CSPRINT CSPIF 2.0 2.09 2.01 2.02 1.23 3.12.19 2.01 4.09.24 2.10 2.09 2.02 2.03 1.25 4.18.24 2.02 4.09.24 3.0 3.03 3.01 3.00 1.29 4.18.25 2.05 4.09.25 Note that not all Netware files are not included in the above chart. We strongly recommend that Netware users have Stationware for Netware v3.0 for proper operation. When running CSCONFIG, the LTE, LPS, and LDU modules are found in Stationware Maintenance. The NETDRV is found in Central Station System Software. The CSPPORT, CSPRINT, and CSPIF are all .EXE files which are executed on the PC. Stationware software version mis-matches will cause the Central Station to malfunction, or not function at all. After verifying all software modules are correct, cycle power on the Central Station. Watch the indicator lights on the front panel. They should all light up briefly, then go out (except for power). This indicates the Central Station has passed the power-up self test. The first step to attaching a PC to the network is to connect it to the Central Station. In a LANtastic LAN, this is accomplished with the command: CSPPORT In a Netware LAN, the following commands connect the PC to the Central Station: LSL CSPIF The most common problem at this point is the error "Unable to connect to Central Station". There can be several causes for this error. The most common is the parallel port in the computer. There are four type of LPT ports: Printer only - 8-bit writes, 2-bit reads Unidirectional - 8-bit writes, 4-bit reads Bi-directional - 8-bit writes, 8-bit reads (PS/2 type ports) Enhanced - 8-bit writes, 8-bit reads, high speed (Intel "SL" processors have this) Central Station requires the parallel port to have at least 4-bit reads. Some laptop/notebook PCs have configurable LPT ports which allow you to change the status of the LPT port. If the I/O port address of the LPT port is non-standard, the Central Station will not connect using the driver with default settings. To find the I/O address of the computer's ports, use the following DEBUG command: C:\DOS>DEBUG -D 0:400 L 10 ;This will output the following line: 0000:0400 F8 03 F8 02 00 00 00 00 - BC 03 78 02 00 00 00 00 . . . . . . . . . . . . . | COM1 | COM2 | COM3 | COM4| | LPT1 | LPT2 | LPT3 | LPT4 | (the above line is not displayed) -q ;This will exit DEBUG The display shows that LPT1 is at I/O address 03BC, and LPT2 is at 0278 (the bits for each port are reversed in the DEBUG display). So in this case, a LANtastic computer would need the following command: CSPPORT /PORT=LPT1 /IOBASE=3BC /IRQ=7 -or- CSPPORT /PORT=LPT2 /IOBASE=278 /IRQ=5 And a Netware computer would require the following commands: LSL CSPIF /PORT=LPT1 /IOBASE=3BC /IRQ=7 -or- CSPIF /PORT=LPT2 /IOBASE=278 /IRQ=5 If this fails, you may need to remove the parallel port not being used, to verify there are no hardware conflicts within the computer. If it still fails, try different computers, to determine if this computer's parallel ports are capable of at least 4-bit reads. The first step to printing at the Central Station is to configure the printer ports through CSCONFIG, Stationware Maintenance. Parallel printers are pretty straightforward, however serial printers have settings that need to match the serial port settings. These are the BAUD Rate, Data Bits, Stop Bits, Parity, and Flow Control. Refer to the printer documentation to determine the printer's settings, and match those settings on the port(s) being enabled for LPS. The CSPRINT command is used to redirect printing. Quite simply put, CSPRINT resides in memory and "intercepts" print jobs destined for that computer's printer ports, and redirects them to specific printer ports on a specific Central Station. Consider the small LAN layout below: Station Server SV1 Server SV2 Þ Þ ÚÄÄÄÄÄÄÄÄÄ¿ Þ Serial Printer ÚÄÄÄÄÄ¿ ÚÄÄÄÄÄ¿ ³ @PRINTER³ ÚÄÄÄÄÄ¿ Ú> On COM1 ³ ³ ³ ³ ³ Physical³ ³ ³ ³ ³ ³ ³ ³ ³ LPT1 on ³ ³ ³ ³ Parallel Printer ÀÄÄÄÄÄÙ ÀÄÄÄÄÄÙ ³ SV1 ³ ÀÄÄÄÄÄÙ ³ ÚÄÄÄ> On LPT1 Ú¿ Ú¿ÀÄÄÄÄÄÄÄÄÄÙ Ú¿ ÚÄÁÄÁÄÄÄÄ¿ ³þþþþþþþÃÄÄÄ´þþþþþþþÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´þþþþþþþþÃÄÄÄ´ CS ³ ÀÄÄÄÄÄÄÄÙ ÀÄÄÄÄÄÄÄÙ ÀÄÄÄÄÄÄÄÄÙ ÀÄÄÄÄÄÄÄÄÙ Central Station Server \\SV1 has one shared resource: @PRINTER ===> LPT1 (physical LPT1 port) Server \\SV2 has two shared resources: @CENTLPT ===> LPT2 (logical parallel port) @CENTSER ===> COM1 (logical serial port) CSPRINT is then used to "intercept" print jobs destined for \\SV2's LPT2 and COM1 ports and send them to the Central Station's printer ports. To do this, the STARTNET.BAT file on \\SV2 needs the following commands: NODERUN AILANBIO CSPRINT CENT1 /PCPORT=LPT2 /CSPORT=LPT1 CSPRINT CENT1 /PCPORT=COM1 /CSPORT=COM1 The workstation then uses the following NET USE commands in it's STARTNET.BAT file: NET USE LPT1 \\SV1\@PRINTER NET USE LPT2 \\SV2\@CENTLPT NET USE COM1 \\SV2\@CENTSER Now when the workstation prints to LPT1, it gets redirected to \\SV1\@PRINTER and prints at the \\SV1 parallel printer. However, when the workstation prints to LPT2, it gets redirected to \\SV2\@CENTLPT, which in turn is redirected to the CENT1 LPT1 port, so it prints at the Central Station's parallel printer. If the workstation prints to COM1, it prints at the Central Station's serial printer, using the same redirection path. If the print jobs do not print at the Central Station, plug the printer(s) into a PC to verify the printer(s) are functional. Stationware versions are also critical when using LPS. Refer to page 2 for a chart of valid Stationware versions. When using Central Station as a printing device in the Netware environment, Central Station logs into the Netware file server as a Print Server. To establish this link, there are a few simple steps to follow: Configure Central Station: 1] Using the CSCONFIG program, install the NPS Stationware module, and configure the ports for the type of printers being used. For now, we'll say LPT1 is enabled. 2] Verify or change the Central Station Name (we'll call it CENT1 for now). Configure the Netware File Server: 1] Login to the server using an account with SUPERVISOR privileges. 2] Run PCONSOLE and choose Print Server Information. 3] Hit INS and enter the name of the Central Station, CENT1 (creates a new print server). 4] Hit INS and enter CENT_LPT1 (creates an entry for the port enabled on Central Station). 5] Press ÀÄÄÄÄÄÙ A-> ÀÄÄÄÄÙ A-> ³ Phone ³ \ ÀÄÄÄÄÄÙ D/A A/D->D/A ³ Carrier ³ / ³ A/D->D/A ³ \ ÀÄÄÄÄÄÄÄÄÄÄÙ / \ A ÚÄÄÄÄÄ¿ ÚÄÄÄÄÄ¿ ÚÄÄÄÄ¿ ÚÄÄÄÄÄÄÄÄÄÄ¿ / ³ PC ÃÄÄÄÄÄÄÄÄ´ModemÃÄÄÄÄÄÄÄÄÄÄ´PBX ³\/\/\/\/\/\/³ Local ³ \ ³ ³ <-D ÀÄÄÄÄÄÙ <-A ÀÄÄÄÄÙ <-A ³ Phone ³ / ÀÄÄÄÄÄÙ A/D A/D <-D/A ³ Carrier ³ / ³ A/D<-A/D ³ ÀÄÄÄÄÄÄÄÄÄÄÙ As you can see, the data is switched from Digital to Analog and back ten times in this scenario. This causes too many delays for high speed modem transmissions to be reliable. Bypassing the internal switching equipment at the "punch down block" and connecting the modem directly to the local phone carrier's analog lines eliminates four of the switches, allowing for faster, more reliable data transmissions. In many digital telephone systems, there is no switching to analog, as that is done by the handset of the telephone for voice communications. These systems have a carrier or query signal constantly being transmitted on the line, in use by the phone system to carry the the digital information. While this signal is well above the human hearing threshold, modems do "hear" this signal. This can produce symptoms such as not being able to locate a network server after a successful connection has been made, or the connection will be "broken" during large file transfers. Again, bypassing the digital phone system will solve this problem. NOTE: Do not attempt to bypass, connect modem telephone lines directly to, or make any modification to a telephone punch down block yourself. Doing so could result in possible damage to equipment owned by the local phone carrier, and/or violation of warranties made by the telephone system company. Always have properly qualified personnel from the telephone company involved perform any necessary modifications to the telephone system. To test the modem telephone line, use any Terminal Emulation software to see if the modem will dial into a BBS or other public access service. So now the connection is established successfully, but the data transmission rate is extremely slow, and/or the remote computer continually bleeps when copying large files or executing programs on the server. The first thing to remember is that modems are slow. Ethernet is rated at a maximum transfer rate of 10,000,000 bits per second, while modem's maximum transfer rate is 57,600 bits per second, or about 6% of ethernet speed. It should be noted that the modem manufacture's claim of 57,600 bps transfers are only true under ideal laboratory conditions, with no telephone interference, and using data that is compressible at a ratio of 4:1. Any transmission which contains binary, compiled, or already compressed data cannot be compressed by the modem, and therefore will be transferred at the slower DCE speed, not the DTE speed. In ethernet transmissions using an AE2 card, when a file is copied, Redir passes the information along to Ailanbio which then passes it along to AEX and the nic for processing. Usually, Redir is able to handle the normal latency involved in this process. Why does Redir care? Because during an action like a copy, Redir issues a netbios wait command, which makes it wait until Ailanbio confirms the data was received. Then Ailanbio has to wait until AEX gets the data before it can tell Redir that it is done. In modem transmissions, the LDU connection has to convert modem packets to network packets and back again, each time receiving them from or giving them to Ailanbio. The MPORT driver performs this function on the remote station and LDU does it at the Central Station. LDU on the Central Station takes a standard 1500 byte Ethernet packet and split it into 3 packets of 574 bytes each. This creates the added overhead of using 3 packets to send what normally can be done in 1 and having to wait for 3 ACKs (acknowledgments) instead of 1. LDU then buffers the packets using the Buff Manager program and begins sending the data to the port on the Central Station. The problem with modem connections develops running Mport. Mport is emulating the nic, but clearly cannot process data as quickly as an Ethernet card. So Ailanbio has to wait for Mport and Redir has to wait for Ailanbio. If Redir does not get an immediate response from Ailanbio, then Redir bleeps, indicating a timeout waiting for Ailanbio to finish its request. Ailanbio does not finish the request because of the slow response from the modem. By adding the FORCE_ACK_MODE to the AILANBIO command at the remote computer, the server will be forced to wait for an ACK from the remote before attempting to send another data packet. This will help make data flow more smoothly across the slow modem link. sometimes increasing the ACK_TIMEOUT and RETRY_PERIOD may help, also. The syntax is: MPORT AILANBIO FORCE_ACK_MODE ACK_TIMEOUT=10 RETRY_PERIOD=10 While FORCE_ACK_MODE is recommended for all modem links, the ACK_TIMEOUT and RETRY_PERIOD switches may not improve transmission integrity if there is interference on the phone lines, or the modems are not communicating properly. Following are suggestions to help improve performance when using modem links and LDU: þ Use the fastest modems with compression (v42bis) and error correction (v32bis). Slower modems without these features are more prone the problems discussed above. þ Use identical modems on both ends of the link to ensure proper communication. þ Do not try to load executable files across the modem link. Besides usually being large and taking more time, EXE files can also have alot of overhead associated with them. Many of them have to open config and status files. Some have to swap overlays in and out of memory every time a new command or menu choice is made. EXE files are usually not compressible so they will come across the modem link at the slower DCE rate, which can lead to timeouts. þ Turn off the server ID on the main server if it is not needed. That way it does not broadcast it and waste packets across the slow modem link. þ Do not run any unnecessary TSR'S, including Server, on the remote. Even when they are not active, they take CPU cycles away from Mport. þ Below is a table that gives a general comparison in file transfer rates using the different baud rates. These numbers are relative and actual results may vary. DTE Rate 10k file 100k file 500k file 1 meg file 2400 1 min 9.5 min 47.4 min 94.8 min 9600 15 sec 2.4 min 11.9 min 23.7 min 19200 * 7 sec 1.2 min 5.9 min 11.9 min 38400 * 4 sec 35 sec 2.9 min 5.9 min 57600 * 2 sec 24 sec 1.9 min 3.9 min * Requires data compression by the modems. The DTE rate refers to bits per second. Since there are 10 bits for each byte, and some overhead for packet manipulation, some calculation is required to find these approximate transfer times. The formula is: FILE_SIZE / ((DTE/10) x.75) = transfer time in seconds Calculation method for the above figures for a 10k file (10,240 bytes) at 2400 DTE are based on: 2400 / 10 = 240 bytes per second (1 start bit, 8 data bits, 1 stop bit per byte) 240 x .75 = 180 bytes per second (.75 is the overhead for splitting 1 data packet into 3) 10240 / 180 = 56.9 seconds transfer time (file size divided by bytes per second) Calculations for a 1 megabyte (1,024,000 bytes) file at 57600 DTE rate: 57600 / 10 = 5760 bps 5760 x .75 = 4320 bps 1024000 / 4320 = 237.03 seconds 237 / 60 = 3.95 minutes transfer time Netware Dial-Up (NDU): Netware Dial-Up functions much the same as LANtastic Dial-Up, with all the same issues of modem communication to be considered. Use the CSCONFIG program on Central Station to enable NDU and select the proper modem and settings for that modem. On the remote computer this is done with the DIALER program, located on the Stationware for Netware diskette. For a remote computer to become a client on the Netware server, it needs to run the following programs: LSL NDUWS IPXODI DIALER NETX These programs are located on the Stationware for Netware diskette, and should be copied to the boot drive of the remote computer. Once NETX has connected you to the Netware server, you can run LOGIN to login to the server. Since LOGIN.EXE is a very large file, it should be executed locally from the C: drive, not from the Netware server's F: drive. Once logged in, the remote has all the access as a computer on the LAN, but at the slower modem transmission speeds. Driver statistics can be retrieved by using the DIALER program and choosing Driver Statistics. These can be helpful in determining if there is phone line interference (high CRC errors), if the hardware in the remote computer needs to be upgraded (high Overrun Count), or if excessive data is being sent over the phone lines (high No ECB Count). If these values are all zero, or are very low compared to the number of the Packets Transmitted and Packets Received, you can be assured the modem link is about as good as it is going to get. ARTISOFT, Inc. makes no warranties as to the completeness or accuracy of this document. LANtastic is a trademark of ARTISOFT, Inc. Brand names, company names, and product names are trademarks or registered trademarks of their respective companies. We have several methods, you can use to receive support. Our normal technical support line is 520-670-7000 (7a-5p MT). You can post a message on CompuServe in the Artisoft Forum. CompuServe is answered in 1 business day (if left before 6am MT). You can post a message on the Arti-Facts BBS @ 520-884-8648 or 520-884-9675 (14.4k) [8,n,1]. For immediate access to a technician, you can contact our Express Service @ $2.50/minute with extended hours of 6a-9p MT and 6a-5p MT on Saturday. Express service can be obtained at 1-900-555-8324 (billed to phone) or 1-800-293-3936 with a valid AmEx, MC, or VISA card. Please Note During Daylight Savings our Times are 1 hour earlier.