IP Controller Protects Twinax Investments

With the introduction of its 5500 Express IP Control Unit, IBM is sending a significant message to its AS/400 user base. Organizations that have relied heavily on Twinax connectivity over the years can implement e-business strategies while at the same time protecting their investments in existing network configurations.

The 5500 Express IP Control Unit is an addition to IBM's Express family of products and is designed to bring e-business, Web access and other IP networking capabilities to Twinax devices in remote and/or local environments. Such a device is designed to provide an IP migration path that does not necessitate rewiring and reconfiguration.

"The 5500 primarily targets the installed base of AS/400 customers that have a large installation of Twinax, enabling them to use e-business today over their cabling infrastructure without saying, 'I don't have it in my budget to totally rewire, so I can't go to e-business,'" says Buz Stepanek, product line manager for AS/400 connectivity products in IBM's Networking Hardware Division.

"A large set of AS/400 users are still using fixed-function, non-programmable terminals," Stepanek says. "There are many applications written for that interface, and for many customers, that's all they need from their AS/400."

The 5500 Express IP Control Unit is actually a line of products consisting of four models. The models 01E and 02E are designed to provide: 10Base-T Ethernet and 100Base-TX Fast Ethernet LAN attachments; 10- or 100-Mbps operation through a single RJ-45 connector; auto-negotiation of speed and half-duplex mode or full-duplex mode; and support of UTP cabling via a RJ-45 connector.

The second set of models, the 01T and 02T are designed to provide: dedicated Token-Ring operation when connected to a full-duplex switch; automatic ring-speed detection and selection; adapter and ring status LEDs; support for either UTP or STP cabling via RJ-45 and D-shell connector; and compliance with the IEEE 802.5 Revision 2 standard.

All models of the 5500 line include: a Twinaxial workstation controller capable of supporting 56 Twinax devices; fixed disk containing the Network Station boot code image; diskette drive with a configuration diskette; and two RS-232 WAN ports that support the EIA-232D/V.24 standard. Each port is designed to run at speeds from 110 bps to 115 Kbps and can be configured as either PPP or SLIP.

According to IBM, when used with the 5250 Express devices, the 5500 Express IP Control Unit can improve Twinax throughput by nearly 400 percent. Each of the devices -- which range in price from approximately $4,895 for the 01E to approximately $6,745 for the 02T --supports all 5250 adapters using the TCP/IP over Twinax transport driver. The 5500 line is also designed to complement IBM's 5494 Remote Control Unit for users currently working remotely from the AS/400 host. For installations using both the 5500 and a Frame Relay-connected 5494, a 5500 can be connected to the 5494 via Token-Ring, allowing both to share the WAN.

For customers that already have 5250 adapters, now they can take advantage of IP over Twinax without having to upgrade their AS/400, according to Stepanek. The 5500 connects Twinax devices to the Internet either through local or remote AS/400 hosts, or through a provider. This is an alternative to total network conversion to either an Ethernet or Token-Ring LAN.

"You're not exactly attaching any of the Twinax devices to the AS/400, you're attaching them to the 5500," Stepanek points out. "All the connections from there on are essentially TCP/IP. With the 5500, Twinax devices won't be directly attached to the AS/400."

V4R2 of OS/400 was the first time the AS/400 supported direct attach. "V4R2 includes code that actually does the TCP/IP over Twinax within the operating system itself," Stepanek says. "We've got that same code running in the 5500."

The types of AS/400 users who will be most interested in the 5500, according to Stepanek, are those that have installations of PCs using 5250 adapters, and those who want to use TCP/IP. "Even if a facility has a older version of OS/400 on their AS/400, they will be able to take advantage of TCP/IP over Twinax using the 5500," he adds.

"Some companies still want to use green screen access, but want the network to be connected via Ethernet, you can roll out 5500s with Ethernet-attached [IBM] Network Stations doing 5250 only emulation today, and tomorrow upgrade your AS/400 or add an NT server," Stepanek says. "Your hardware would then all be in place, and you could continue to use the 5500, especially in remote environments, to support any Network Station."

Twinax still has some advantages over newer methods of network connectivity, according to Stepanek. "Depending upon how you have your network laid out and whether you're using switches, if you have many Ethernet devices that are sharing the same piece of wire, the more devices you add the slower the performance," he says. "With the 5500 controller, the number of devices you add is irrelevant. The AS/400 initiates communication with every Twinax-connected device, versus Ethernet, where all devices are trying to get on the same wire at the same time."