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- Modem Pooling in a NetWire Environment
- Making a Choice
- February 26, 1991
-
- It is feasible to provide modem access to and from a NetWare LAN through a
- single point. Many organizations find this cost effective because it
- avoids providing a modem and phone line at every workstation which might
- have a reason to use a modem. A number of companies manufacture products
- which provide this ability. Novell produces, sells, and provides technical
- support for two; Access Server and NACS.
-
- For Calling into A NetWare LAN
- NetWare Access Server
- -------------------------------
- NetWare Access Server software enables up to 15 remote users to dial in to
- a NetWare LAN and access all the services and files available on the
- network including applications, electronic mail and access to mainframes
- and minicomputers. The software turns a DEDICATED 80386 (or 486) Industry
- Standard Architecture (ISA) bus machine into a remote communications server
- by dividing the 386 (or 486) CPU into as many 640KB machines as installed
- RAM allows (up to 16). Each remote user calling in receives one or more of
- the virtual sessions in which to their work.
-
- A 16th session is reserved for network supervisors, allowing them to manage
- the network and remote connections and communicate with remote users.
-
- Remote users can dial into an Access Server through asynchronous modems or
- multiplexers using any PC or Macintosh, or most ASCII terminals.
- "ONLAN/PC" and "ONLAN/Mac" are provided with the Access Server and provide
- a particularly smooth interface with Access Server. However, many terminal
- emulation programs may be used a substitute for ONLAN/ONLANMAC with some
- limitations. "ONFILE" is also included with the Access Server software and
- is the only supported method of file transfer. Each owner of an Access
- Server is authorized to provide unlimited copies of ONLAN/PC and ONLANMAC
- to any site which may call the Access Server.
-
- Because all processing is handled by Access Server, only screen updates and
- keystrokes travel over the asynchronous lines and file access occurs at LAN
- speeds.
-
- Besides normal NetWare security there are number of specific Access Server
- security features which optionally may be used including:
- - Dial Back" which does not allow a caller to have a session until
- they have been called back at a telephone number specified by the
- network supervisor.
-
- Access Server allows the use of expanded memory above the 640 base for each
- individual session.
-
- For more information about Access Server see ACERUL.TXT in NOVA Library 9
- (Communications). ACERUL.TXT is the "Rules of Thumb" for Access Server and
- it is important that you read it before making any decisions regarding
- hardware (including modems) and software to use with Access Server.
-
- For Calling Into or Out of a NetWare LAN
- NACS
- ---------------------------------------------
- The NetWare Asychronous Communications Server (NACS) turns a DEDICATED IBM
- PC/IBM PC AT or compatible into an asychronous communications server that
- allows up to 16 network stations to simultaneously call out of a LAN or to
- be accessed by a call into the LAN.
-
- Unlike Access Server, applications are not processed within the NACS but
- calls simply go through the WNIM+ ports on the NACS instead of the PCs COMM
- port. Users only have to specify a port by name in order to connect to a
- particular modem or line. In addition, NACS is capable of "rotating" if a
- port is busy.
-
- The recommended hardware for a NACS is:
- - An IBM AT or close compatible (but an XT or compatible will work)
- with:
- - A CGA OR MONOCHROME Video Adapter (Has no effect on caller's
- displays)
- - Not more 512K RAM (will run but not configure with 256K)
- - 10 MHz or more
- - In addition the following is REQUIRED:
- - One WNIM or WNIM+ card for each 4 simultaneous connections.
- - "NASI Compatible" communications software. (A list is provided
- in NACCOM.TXT in NOVA Library 9.
- - One asynchronous modem for each port to be used. (A NACS can
- also be connected directly to the asychronous ports on a Mini or
- Mainframe computer.)
- - The NACS machine may not have a microchannel bus.
-
-
- The Decision
- ------------
- NOTE: There is no practical special limit on the number of Access Servers
- and NACS that can coexist on the same LAN.
-
- 1. For the best support for incoming calls Access Server is recommended.
-
- 2. For the best support for outgoing calls NACS is recommended.
-
- 3. For a LAN with a large amount of outgoing calls and a small amount of
- incoming calls NACS is recommended. However, each incoming call will a
- require a separate workstation in "call waiting status". With appropriate
- "NASI Compatible" software.
-
- 4. For a LAN with a large amount of outgoing calls AND a large amount of
- incoming we recommend that both an Access Server and a NACS be secured.
-
- 5. If there will only be 1 or 2 simultaneous incoming or outgoing calls at
- one time and you do not require the special feature of Access Server or
- NACS you may wish to explore third party products.
-
-
- Limitations
- -----------
- 1. The large amount of data required to be transmitted across the phone
- lines for intensive graphics makes asynchronous remote use less than
- completely practical for such applications.
-
- 2. Mice and similar tracking devices do not lend themselves to use across
- asychronous lines.
-
- 3. Windows will not run in an Access Server.
-