Specifications

Escala Tower PL & S, E, T System Hardware
Chapter 3: External Storage and SAN Subsystems 82/116
9es3s1c3.doc
Rev 5.9
02/12/2003
6.3.4. Zoning, Switched Loops, Mix of Private Loops and Fabrics
Using these basic topologies and protocols to operate in private or public loop and fabric
environments, various features have been implemented by the SAN infrastructure vendors. These
features are proprietary, usually compatible with Fibre Channel standards and bring new
interconnection and operation capabilities.
6.3.4.1. Fabric Zoning
Fabric zoning is a feature that allows to create several logical areas on a single physical fibre channel
network. Devices such as servers or disk subsystems can only communicate with other devices in the
same zone. In some implementations, zones can overlap. This means that a device can belong to
several zones.
fabric
Zone A
Zone B
Zone C
Zoning can be used as a security service, preventing some resource to be used by non authorized users:
a disk subsystem with confidential data can be isolated in a zone of authorized servers.
Zoning can also be used to solve some interoperability problems: a zone can be defined for all the
servers and storage resources used by AIX servers, another zone being dedicated to NT servers and
NT storage resources.
6.3.4.2. Loop Zoning
Loop zoning is a feature that allows to create several independent loops, through the same hub. The
zoned loops are usually defined by a list of hub's ports. Contrarily to fabric zoning, its usually not
possible to define overlapping zones, nor zones across multiple interconnected hubs. The zoned loops
can be enforced at the hardware level (by splitting the hub's internal loop), or emulated by software.