Factors To Consider When Implementing A Fabric Topology - HP 316095-B21 - StorageWorks Edge Switch 2/24 Planning Manual

Planning Considerations for Fibre Channel Topologies
Note:
path, not the total number of ISL connections between devices. As shown in
the number of ISL connections between Switch S
hops is 1.

Factors to Consider When Implementing a Fabric Topology

Director and switch-based fabrics offer scalable, high-performance, and
high-availability connectivity solutions for the enterprise. To enable a
multi-switch fabric, all fabric elements must be defined to the HAFM application
and must be physically cabled to form the requisite ISL connections. In addition,
HP recommends that each director or switch in the fabric be assigned a unique
preferred domain ID.
When planning to implement a fabric topology, consider the following
connectivity and cabling concepts:
82
The hop count is equal to the number of ISL connections traversed in a single
Physical characteristics and performance objectives — Most enterprises
have unique configurations determined by the characteristics of end devices,
fabric elements, cost, and the installation's performance objectives (such as
high data transfer rate or high availability). These factors, along with
nondisruptive growth and service requirements, must be evaluated when
planning an initial fabric. For additional information, refer to
Fibre Channel Fabric
Distance requirements — The distance between elements in a fabric affects
the type of optical port transceiver and cabling required. In addition, variables
such as the number of connections, grade of fiber-optic cable, device
restrictions, application restrictions, buffer-to-buffer credit limits, and
performance requirements can affect distance requirements. Consider the
following:
— If the distance between two fabric elements is less than 250 meters (at
2.125 Gbps), any port type (shortwave or longwave laser) and any
fiber-optic cable type (multimode or single-mode) can be used to create
an ISL connection. In this case, cost or port availability may be the
determining factor.
— If the distance between two fabric elements exceeds 300 meters (at 2.125
Gbps), only longwave laser ports and single-mode fiber-optic cable can
be used to create an ISL.
1
Topology" on page 99.
and S is 4, while the number of
2
"Planning a
SAN High Availability Planning Guide
Figure 35,