ISL stands for:
a.Inter switch link.
b. Isolated structured link.
c. Interoperable and scalable link.
d. Incredibly secure link.
Were you correct? The correct answer is
a. Inter switch link.
Switches are used to create the "fabric" part of a SAN fabric. The reason we use switches in a SAN is to create a network so the expensive storage resources like disk arrays and tape libraries can be shared between many servers.
Storage arrays have a limited number of physical ports. If we connected every server directly to a storage port (this can be done) it would limit the total number of servers that could share the storage inside the array. Hooking up one physical storage port to a 16-port switch, allows you to connect up to 15 servers to that single physical port. This way, a single port can provide storage for many servers. This is known as the "fan-in-ratio" of the port. Figuring out how many servers should share a single port is an art in itself. Some storage vendors limit you to 16 or less. Some let you connect up to 128 servers per port.
matrix: 2G bit/sec. fabric switches
scalability, part 1: Account for fabric reconfigurations in the SAN
haven't FC HBAs followed FC switch price declines?
- Maximize locality when setting up a SAN
This was first published in January 2004