Specifications

Escala Tower PL & S, E, T System Hardware
Chapter 3: External Storage and SAN Subsystems 81/116
9es3s1c3.doc
Rev 5.9
02/12/2003
Multiple inter-switch links can be aggregated, to avoid the risk of bandwidth bottleneck that may arise
when using a single link operating at the same speed than the switch ports.
switch switch
100 MB/s or
200 MB/s
100 MB/s or
200 MB/s
3 x 100 MB/s or
3 x 200 MB/s
potential
4x100 MB/s or
4x 200 MB/s
aggregation
of 4 links
100 MB/s or
200 MB/s
100 MB/s or
200 MB/s
100 MB/s or
200 MB/s
100 MB/s or
200 MB/s
3 x 100 MB/s or
3 x 200 MB/s
potential
A single link could be a
bottleneck
6.3.3.4. Interconnection of Fabrics and Loops
Fabric and switch ports are quite expensive. Thus, the Fibre Channel standards enable to mix switches
and hubs. A switch port can be shared between multiple devices, connected through a hub, to the
switch's port. They share the 100 MB/s or 200 MB/s offered by the switch's port. Such devices are
named "public loop devices". They can communicate with any other devices of the fabric or of other
public loops. The public loops are always connected at the edge of a fabric. Loops and hubs cannot be
used to interconnect switches.
Fabric and
p
ublic loo
p
s
fabric
switch switch
switchswitch
switch
Public loo
p
Public loo
p