HP StorageWorks 8B FC Entry Switch - Manual (Page 18)

3-4 ISL Trunking User’s Guide
Using ISL Trunking
3
Frequently Asked Questions about ISL Trunking
The following table lists Frequently Asked Questions about the ISL Trunking feature:
Table 3-4 Frequently Asked Questions about ISL Trunking
Frequently Asked Questions Answers
Does ISL Trunking replace Dense Wavelength
Digital Multiplexing (DWDM)? No. DWDM is a ring, and if a failure occurs it
reroutes the allocated wavelength over alternate
routes, and therefore changes the effective
cable lengths.
What happens if an ISL in the trunk slave port
fails? If one of the trunk slave ports fails, the logical
ISL stays up, however, its capacity is reduced
by 2Gb/Sec, and no route failure or re-routing
of traffic occurs.
What happens if a trunk master fails? If a trunk master fails, the ISL goes down, and
FSFP perceives a momentary route failure. The
trunk immediately re-forms without the failed
ISL, and traffic resumes over the re-formed
trunk with capacity reduced by 2Gb/sec.
Are trunks automatically established when the
trunking feature is enabled? Yes. Trunks are automatically established on
available ports when the trunking feature is
enabled.
Is it possible to have more than one trunk
between a pair of switches? Yes.
Is there a limit on the number of trunks I can
have on one switch? No.
Is there a limit on the number of trunks I can
have between a pair of switches? No.
Is it possible to trunk between a switch and an
edge devices host or storage? No.
Should port statistics be the same across all
participating ISLs within a trunk? Not necessarily, it depends on the payload
variations at the frame level. While optimal
bandwidth utilization is the goal of the ISL
Trunking feature, traffic might not be
distributed exactly the same across all ISL links
within a trunk.