The 7318 Model S20 Guide and Reference contains information to set up and attach terminals, printers, and modems to a 7318. The guide also provides guidelines for cabling your network.
This guide contains specific information on installing and configuring the 7318 Model S20.
Refer to Chapter 8, "Serial Communications Network Server (7318)," in the AIX Versions 3.2 and 4 Asynchronous Communications Guide for information specific to the 7318 Model P10.
The 7318 Serial Communications Network Server is a multiprotocol communications server that connects serial and parallel ports onto an Ethernet. There are two models of the 7318, the Model P10 and S20. Both models have the same physical connectivity and appearance; however, the model S20 supports standard TCP/IP protocols in addition to the complete functionality of the Model P10.
The 7318 Model P10 and S20 provide for attachment of 16 serial asynchronous devices and two parallel printers to one or more systems utilizing standard Ethernet wiring and an Ethernet interface. The 7318 Model P10 is unique when compared to other Ethernet "terminal servers" in that the attached devices appear as native devices attached through a multiport adapter.
This capability gives the user all the flexibility of Ethernet terminal servers with all the advantages of a multiport adapter. For instance, terminal users can connect directly to one or more systems on the network without being dependent on one system. Systems can also share devices attached to the 7318 Model P10. These connectivity advantages are provided while at the same time providing the same configurability and control as a native serial and parallel port.
The 7318 Models P10 and S20 connect to the system over Ethernet wiring. For systems that have integrated ethernet, the 7318 has an advantage over multiport boards in that it consumes no adapter card slots. Model P10 ports are attached to systems using network cabling. The network is made transparent to the user because the devices appear to be locally attached TTY or LP devices.
The 7318 Model S20 ports can be configured to operate the same as a Model P10 port or can be used to take full advantage of a network environment. The Model S20 supports standard TCP/IP networking protocols, telnet and rlogin, which can be used to communicate to any similarly capable systems on the network. The Model S20 also supports 3270 terminal emulation for communication with applications like CICS/6000 or for communication with large systems. The 7318 Model S20 can also provide remote dial-in users with network access, using SLIP, CSLIP or PPP serial line networking protocols. Dial-in users are able to run TCP/IP applications similar to other users locally attached to the network.
Both the Model P10 and the Model S20 have network security support. The Model P10 port or the Model S20 port configured as a P10 port can only communicate to systems configured for that 7318 port. Users have the same network access as a user attached to the native serial port. The Model S20 can be configured for local or remote password security or Kerberos V.5 password authentication. Kerberos V.5 uses the DES encryption algorithm to prevent passwords from being sent across the network. The Model S20 also has the capability to encrypt all the data associated with an rlogin application. Remote password security allows password management across multiple 7318s from a centralized database.
The Model S20 has the capability to take full advantage of the Network Terminal Accelerator features. The combination of the 7318 Model S20 and Network Terminal Accelerator eliminates the networking overhead of TCP/IP, telnetd, and rlogind. This combination enables the system to support more users or more applications than before.
The 7318 Model S20 Ethernet Attached Async figure provides a more complete overview of the 7318 Model S20.
Ethernet cabling provides flexible wiring options including unshielded twisted pair and two types of coax. Distances can be extended using up to four repeaters for a maximum of five segments.
Attachment to the system requires an Ethernet interface. For many systems, this will not require an adapter card slot.
Up to four 7318s may be daisy-chained together utilizing only one Ethernet connection (node).
Ethernet wiring can be used for purposes other than attaching 7318s. The 7318 Model P10 utilizes Novell's SPX/IPX protocols, which are interoperable with other Ethernet protocols.
The 7318 supports 10 Mbps Ethernet, 10Base-T, 10Base-2, and 10Base-5.
The 16 serial ports support data rates up to 115.2 Kbps with certain limitations. All 16 serial ports are RS-423 and RS-232 compatible. Up to 16 RS-422 devices are supported with limitations. The maximum cable distance supported for an RS-232D device is 200 ft, while the maximum cable distance supported for an RS-423 or RS-422 device is 2300 ft at 9600bps. Two PC-compatible parallel ports are also provided for faster printing with burst data rates up to 100 KBps.
Systems can be configured to share 7318s, 7318 ports and devices, or terminal users attached to the 7318 can login to multiple systems simultaneously using multiple sessions.
Using Ethernet and TCP/IP applications telnet and rlogin, the 7318 Model S20 can provide terminal users with a login session on any system with telnet and rlogin support attached to the network.
To IPL and become fully functional, the 7318 must fetch its operating system from a system on the network. This load host can be any system; however, the distribution media used for the 7318 software is an AIX-specific format.
The 7318 Model S20 supports TN3270 terminal emulation. This function enables users with an ASCII terminal to log in to a large system running VM or MVS operating systems supporting TCP/IP. This function is also useful for applications like CICS/6000 which typically consume system resources converting 3270 data streams to ASCII terminal formats.
The 7318 can be used as a dial-up network server, providing remote users with network access using modems. With popular SLIP, CSLIP and PPP protocols and TCP/IP, users can transfer files, receive or send network mail, and run other network applications remotely.
For critical security applications where user passwords cannot be transmitted on a network, the 7318 Model S20 supports Kerberos V.5 password authentication. Additional protection is available through DES data encryption of rlogin sessions and host access restrictions.
The 7318 Model S20 supports all the functions of the Model P10 when attached to an RS/6000 running AIX.
The 7318 Model S20 takes advantage of the performance benefit provided by the Network Terminal Accelerator features. Network Terminal Accelerator significantly reduces the CPU resources consumed by telnet and rlogin protocol overhead. Connectivity can be expanded up to 2048 sessions per Network Terminal Accelerator-2048 feature.
