Sun Microsystems StorEdge, Troubleshooting Manual

Page: 25 / 168

Chapter 1 Introduction 7
Cascading Switches (E_Ports)
Note –
See
TABLE 2-9
on page 19 and
TABLE 2-10
on page 20 for a comparison of the
port nomenclature differences between Sun StorEdge and Brocade Communications
Systems, Inc.
In the Sun StorEdge SAN 4.0 release, switches are allowed to be cascaded together
by using E_Ports. This cascading is allowed with either a shortwave or longwave
Small Form Factor Pluggable (SFP) 2-gigabit transceiver. The use of shortwave SFPs
allows a higher port count in a local configuration. The use of longwave SFPs and
long haul fiber optics allows users to reach geographically separated storage and
servers, perhaps for disaster recovery purposes.
The following limitations exist for cascading with the Sun STorEdge SAN 4.0 release:
■
If 1- and 2-gigabit switches are used together, a maximum of 16 switches can be
cascaded.
■
If only 2-gigabit switches are used, a maximum of 64 switches can be cascaded.
■
The maximum distance is 10 kilometers.
■
Any number of ISL hops can be used between two switches. ISL hops do not
include the connections between hosts and switches or between switches and
storage.
■
A maximum of 8 switches with 7 ISL links between the switches can be cascaded
in a linear fashion.