San Routing - McDATA StorageWorks 2/140 - Director Switch Planning Manual

Implementing SAN Internetworking Solutions
4

SAN Routing

McDATA Products in a SAN Environment - Planning Manual
4-8
Connecting isolated, department-level, and application-specific Fibre
Channel SANs is a requirement for most enterprises. Consolidating
SAN islands:
• Provides campus storage connectivity and interoperability
between formerly-incompatible Fibre Channel fabrics (from the
same or different vendors).
• Allows construction of large Fibre Channel fabrics (up to or
exceeding 239 directors or fabric switches), while reducing fabric
rebuild disruptions and retaining secure partitioning of network
resources through autonomous management domains.
• Provides a stable, long-distance connection over a wide area
network that allows content sharing over regional distances,
consolidates remote tape backup, and implements BC/DR
solutions.
• Allows the enterprise to implement newer technologies and
protocols (such as iSCSI) while preserving investment in a Fibre
Channel infrastructure.
However, connecting Fibre Channel fabrics is not a simple process of
cabling ports together. Fibre Channel architecture provides several
fabric services that require attention to ensure device interoperability
and stability of the consolidated SAN. A robust approach to solve this
connectivity problem is secure, multi-protocol SAN routing.
A routed SAN consists of multiple Fibre Channel fabrics functioning
as a single network, providing any-to-any device connectivity, but
maintaining desired autonomous characteristics of individual fabrics.
Storage networking devices that connect fabric elements in such a
manner are called SAN Routers. Routed SANs typically include
directors and fabric switches from different vendors, operating in
mixed modes, using different protocols (such as Fibre Channel and
iSCSI), and using several firmware versions.
Multi-protocol SAN routing provides larger-scale SAN connectivity
without compromising the ease of administration, high device
availability, and security inherent to SAN islands.
illustrates a three-tier model that defines SAN routing hierarchy:
• Tier 1 - The first tier consists of isolated Fibre Channel fabrics
(SAN islands). Within each fabric, data is transmitted between
directors and fabric switches through E_Port ISLs.
Figure 4-2