SAN Solution Installation Guide

Topologies and Components
Topologies
Chapter 11-4
Topologies
Topology describes the way nodes on a network are connected. These
nodes can be servers and storage systems, as well as interconnected
devices such as hubs, switches and bridges.
Types of topologies include:
• Point-to-Point - A dedicated Fibre Channel connection between two
devices.
• Arbitrated Loop - A shared 100MBps Fibre Channel transport
supporting up to 126 devices and one fabric attachment.
• Switched Fabric - One or more switches providing higher level
services and switched 100MBps bandwidth per port. Maximum
number of nodes = 16 million addresses +/-, maximum bandwidth =
100MBps/ x nodes.
Point-to Point is the most simple of SAN connectivity topologies that
allows bi-directional communication between two nodes, such as a server
and tape library. Between these two nodes is a dedicated fiber-optic
connection.
Arbitrated Loop is a continuous ring configuration where each node
translates or passes data to adjacent nodes. The SAN hub arbitrates
requests for data to make optimum use of the available bandwidth.
Switched Fabric is a new term established to support fiber-optic SAN
technology and describes extensive storage networks where numerous
servers and storage devices are connected using fiber-optic switches.
These switches can be cascaded and combined with loops to create
interwoven networks known as fabrics. This configuration is managed by
software that uses the SAN management capabilities that are built
directly into the fabric scheme.