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Technology Stocks : McData (MCDT) -- Ignore unavailable to you. Want to Upgrade?

To: ColtonGang who wrote (34)	8/19/2000 4:34:13 PM
From: Gus	Read Replies (2) \| Respond to of 234

Fabric Switches and Directors There are two types of high-performance Fibre Channel SAN interconnect devices — director and fabric switches. A director is a class of large switch, placed at the core of the network, offering 32 or more ports, with high availability and redundant features embedded throughout the design. A fabric switch provides eight or more port connections for connecting servers and storage with little or no built-in redundancy. Various degrees of resilience and scalability can be designed into a SAN using either directors or fabric switches; however, *the selection of where to use each is dictated by the requirements of the business.* Enterprise SANs require director-class switches which are defined by port count, automatic failover and redundant components such as redundant logic and firmware, non-disruptive microcode download, and hot-swappable everything - not just redundant power and cooling. Where connectivity and performance are required for enterprise critical fabric connections, a director is designed to deliver the highest level of “core layer” reliability. Multiple directors can be interconnected to support higher port counts. Mission critical applications are typically implemented using dual directors for the best levels of high availability, resiliency and scalability. The major differences between a fabric-class switch and a director-class switch are summarized in Table 3. Note that director is designed to eliminate all single points of failure and maximize bandwidth scalability. The fault tolerant features and bandwidth scalability of a director make it the only choice for enterprise SAN connectivity. While an argument could be made that redundant switches can provide the equivalent capabilities of a director, there are significant reliability, scalability, maintainability and serviceability exposures to this approach. Again, the analogies of other IT disciplines are applicable,i.e. large number of PCs would not be considered adequate to implement a critical business system, nor would a rack of eight- or 16-port Ethernet switches be used to implement a core-to-edge enterprise backbone. Table 3 Director/Fibre Switch Comparison FEATURE: All critical components except ports are redundant with automatic internal failover? Director - YES Fabric Switch - NO (maybe power and cooling) *FEATURE: All critical components are hot replaceable?* Director - YES Fabric Switch - NO (maybe power, cooling, and GBICs) *FEATURE: Non-disruptive code loads?* Director - YES Fabric Switch - NO *FEATURE: Non-disruptive upgrades?* Director - YES Fabric Switch - NO *FEATURE: Component-level fault isolation?* Director - YES Fabric Switch - NO *FEATURE: Maximum ports?* Director - 32 Fabric Switch - 16 QUALITY OF CONNECTION mcdata.com