Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Technology Stocks : The New QLogic (ANCR) -- Ignore unavailable to you. Want to Upgrade?

To: Roger Arquilla who wrote (12677)	11/27/1997 5:10:00 PM
From: Eleleth	Read Replies (1) \| Respond to of 29386

Roger: I did you read George's Los Alamos link, too? cic-5.lanl.gov I had similar questions about HIPPI vs Fibre Channel. The articles are a little old ('95) but offered great insight into the history of gigabit protocols and had some very interesting and unbiased things to say about Fibre Channel. Some highlights: HIGH HOPES FOR HIPPI For all its strengths, HIPPI is hardly standing still. Work is under way to improve the technology and integrate it with other networking schemes. For instance, a HIPPI MIB proposal is being prepared for SNMP. It features self-discovery of switch addresses and address resolution between MAC (media access control) addresses and HIPPI addresses. Developers also are working on performance and capacity planning applications and exploring ways to integrate HIPPI network management with OpenView, NetView, and other platforms. HIPPI interoperability with ATM, Fibre Channel, and SONET also is garnering a great deal of interest. Because of ATM's strong momentum, some in the industry assume that it will displace HIPPI. But such a scenario isn't likely--if for no other reason than simple arithmetic. Any of today's ATM switches can deliver an aggregate bandwidth of 3.2 Gbit/s. That's fast, but it pales in comparison to the 12.8 to 25.6 Gbit/s offered by HIPPI switches. In addition, the ATM market is primarily focused on services at 155 Mbit/s and below, with particular interest in 25 Mbit/s. That may be what many users want, but it cannot satisfy the significant number of users who need gigabit throughput right now. Finally, HIPPI--unlike ATM--allows storage devices to be directly connected to a network at high speeds.That's a critical concern, since end-users on high-speed networks must be able to access compute and storage servers. Actually, it's not a question of HIPPI or ATM. A gateway from a HIPPI workstation cluster to ATM would give end-users the best of both worlds: the unsurpassed throughput of HIPPI in the local area and the ATM's wide-area connectivity. With such a gateway, even multimedia data could fan out from HlPPI-attached servers to multiple ATM desktops. Sounds great, but creating such a gateway is hardly a trivial undertaking. HIPPI is a connection-oriented, circuit-switched transport. ATM is a connection-oriented, cell-switched scheme. HIPPI can handle raw HIPPI, as well as IP and IPI-3 datagrams. ATM slices and dices everything into 53-byte cells. For all the complexity, though, the ANSI committee and the HIPPI Networking Forum are hammering out HIPPI-ATM interfaces. HIPPI-ATM connections work by encapsulating HIPPI data, shipping it over the ATM network, and then reconstituting the HIPPI data and format at the other end. In other words, HIPPI is tunneled through the ATM network. This is done at AAL5 (ATM adaptation layer 5). NetStar is beta-testing a version of its GigaRouter with a HIPPI-ATM interface based on this draft standard. GTE's HIPPI-ATM switch uses an interface based on an earlier version of some of this work. HIPPI AND FIBRE CHANNEL Ironically enough, HIPPI and Fibre Channel are both the work of the same ANSI committee, X3T11. Unlike HIPPI, however, Fibre Channel is marked by complexity. It specifies four data rates, three kinds of media, four transmitter types, three distance categories, three classes of service, and three possible fabrics. The idea was to make sure that Fibre Channel was very rich in features, an ambitious and admirable goal. Unfortunately, it also has meant that Fibre Channel products have been slow to make it to market. And those that have emerged thus far generally run at 200 Mbit/s (266 Mbit/s signalingspeed), a quarter of the standard's highest rated speed. Despite their differences, HIPPI and Fibre Channel can be complementary technologies. An ANSI standard has already been defined that specifies how to send upper-layer Fibre Channel protocols over the lower-layer HIPPI media. The complementary ANSI standard (defining how to ship HIPPI upper-layer protocol over Fibre Channel lower-layer media) is in process. IP-level routing offers another way to map HIPPI to Fibre Channel, and vice versa. At the High-Performance Computing and Networking Conference in Milan, Italy, both HIPPI and Fibre channel were deployed on the backbone network used for the Technology Demonstration Display.