HP StorageWorks 8B - FC Entry Switch User manual

user's guide
version 3.0
isl trunking
www.hp.com

Notice
© Hewlett-Packard Company, 2001. All rights reserved.
Edition: E1201
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ISL Trunking User’s Guide iii
Contents
Preface
About This Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Related Publications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Getting Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Getting Software Updates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Chapter 1 Introducing ISL Trunking
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Advantages of ISL Trunking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Trunking Groups, Ports and Masters . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Chapter 2 Installing ISL Trunking
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Installing ISL Trunking through Telnet . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Installing ISL Trunking through Web Tools. . . . . . . . . . . . . . . . . . . . . . 2-2
Chapter 3 Using ISL Trunking
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Administering ISL Trunking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Frequently Asked Questions about ISL Trunking . . . . . . . . . . . . . . . . . 3-4
Glossary
Index

iv ISL Trunking User’s Guide

ISL Trunking User’s Guide v
Preface
ISL Trunking is a licensed option that requires a valid license key to function. It is included and
enabled in switches with the performance upgrade option. It is supported for the HP Surestore FC
1Gb/2Gb Entry Switch 8B, FC 1Gb/2Gb Switch 8B, and FC 1Gb/2Gb Switch 16B products using
Fabric OS version 3.0.1b or later.
About This Guide
This guide provides the following information about ISL Trunking:
Related Publications
Related product information can be found in the following publications.
Provided with the FC Entry Switch 8B and FC Switch 8B:
•HP Surestore FC 1Gb/2Gb Entry Switch 8B and FC 1Gb/2Gb Switch 8B Getting Started
Guide (A7346-90902)
•HP Surestore FC 1Gb/2Gb Entry Switch 8B and FC 1Gb/2Gb Switch 8B Documentation
CD (A7346-11001)
Chapter 1
Introducing ISL Trunking Overview of the ISL Trunking feature.
Chapter 2
Installing ISL Trunking Instructions for installing an ISL Trunking license key.
Chapter 3
Using ISL Trunking Information on how to use the ISL Trunking feature with telnet commands or Web Tools. This chapter also includes a
Frequently Asked Questions section.

vi ISL Trunking User’s Guide
Provided on the FC Entry Switch 8B and FC Switch 8B Documentation CD, and at the HP Web site
at http://www.hp.com/support/fc8B:
•HP Surestore FC 1Gb/2Gb Entry Switch 8B and FC 1Gb/2Gb Switch 8B Getting Started
Guide (A7346-90902)
•HP Surestore FC 1Gb/2Gb Entry Switch 8B and FC 1Gb/2Gb Switch 8B Installation and
Reference Guide
•Fabric OS Reference Manual, version 3.0
•Fabric OS Procedures Guide, version 3.0
•Fabric OS Version 3.0.1b Release Notes
•Fabric Watch User’s Guide, version 3.0
•QuickLoop User’s Guide, version 3.0
•Web Tools User’s Guide, version 3.0
•Distributed Fabrics User’s Guide, version 3.0
•Zoning User’s Guide, version 3.0
•MIB Reference Manual, version 3.0
•ISL Trunking User’s Guide, version 3.0
•Advanced Performance Monitoring User’s Guide, version 3.0
•Merging Heterogeneous Fabrics Instructions
Provided with the FC 16B:
•HP Surestore FC 1Gb/2Gb Switch 16B Quick Start Guide (A7340-96002)
•HP Surestore FC 1Gb/2Gb Switch 16B Documentation CD (A7340-11001)
Provided on the FC 1Gb/2Gb Switch 16B Documentation CD and at the HP Web site at
http://www.hp.com/support/fc16B:
•HP Surestore FC 1Gb/2Gb Switch 16B Quick Start Guide (A7340-96002)
•HP Surestore FC 1Gb/2Gb Switch 16B Installation and Reference Guide
•Fabric OS Reference Manual, version 3.0
•Fabric OS Procedures Guide, version 3.0
•Fabric OS Version 3.0.1 Release Notes
•Fabric Watch User’s Guide, version 3.0
•QuickLoop User’s Guide, version 3.0
•Web Tools User’s Guide, version 3.0
•Distributed Fabrics User’s Guide, version 3.0
•Zoning User’s Guide, version 3.0
•MIB Reference Manual, version 3.0
•ISL Trunking User’s Guide, version 3.0
•Advanced Performance Monitoring User’s Guide, version 3.0
•Merging Heterogeneous Fabrics Instructions
Information about Fibre Channel standards and Fibre Channel in general can be found on the Fibre
Channel Industry Association Web site, located at http://www.fibrechannel.com.

ISL Trunking User’s Guide vii
Getting Help
For information for the FC Entry Switch 8B and FC Switch 8B, visit the HP Web site at
http://www.hp.com/support/fc8B.For the most current technical support information for the
FC 16B, visit the HP Web site at http://www.hp.com/support/fc16B. This includes hardware and
software support, all repairs, and spare components.
Be prepared to provide the following information to the support personnel:
•Switch serial number
•Switch world wide name
•Output from the supportShow telnet command
•Detailed description of the problem
•Topology configuration
•Troubleshooting steps already performed
Getting Software Updates
For information on obtaining software updates contact your HP account representative or technical
support.

viii ISL Trunking User’s Guide

ISL Trunking User’s Guide 1-1
Chapter
1
Introducing ISL Trunking
This chapter provides the following information:
•Overview on page 1-1
•Advantages of ISL Trunking on page 1-1
•Trunking Groups, Ports and Masters on page 1-3
Overview
Interswitch Link (ISL) Trunking is an optionally licensed product available on the FC Entry Switch
8B, FC Switch 8B, and FC 16B switches with Fabric OS version 3.0.1b or later. ISL Trunking is
managed using telnet commands or the Web Tools interface.
The ISL Trunking feature allows up to four ISLs, connections between two switches through an
Expansion Port (E_Port), to merge logically into a single link. When using ISL Trunking to
aggregate bandwidth of up to four ports, the throughput of the ISLs between switches in a fabric is
quadrupled. For example, at 2 Gb/Sec speeds, ISL Trunking delivers ISL throughput of up to 8
Gb/Sec.
ISL Trunking also supports high-bandwidth, large-scale Storage Area Networks (SANs) which
include core switches. The primary task of ISL Trunking is to route data and edge switches that
aggregate connections to servers and storage. ISL Trunking simplifies network design and reduces
the cost of storage management by optimizing bandwidth utilization and enabling load sharing of
traffic at the frame-level.
For a list of frequently asked questions about the ISL Trunking Feature, refer to Frequently Asked
Questions about ISL Trunking on page 3-4.
Advantages of ISL Trunking
The ISL Trunking feature enhances switch to switch performance in Storage Area Networks while
simplifying management and improving reliability. Advantages of the ISL Trunking feature
include:
•Combining up to four ISLs into a single logical ISL
•Load sharing traffic across all ISLs in a trunk
•Maintaining in-order delivery of frames
•Avoiding rerouting if one of the server links between two switches fails
•Simplifying management by implementing fewer ISLs

1-2 ISL Trunking User’s Guide
Introducing ISL Trunking
1
Routing without the ISL Trunking Feature
Prior to the implementation of the ISL Trunking feature, device-level load sharing was done
through Fibre Channel networks that created ISLs and operated with the Fibre Channel Shortest
Path First (FSPF) routing protocol. The protocol established and communicated the shortest paths
for data to be carried from source to destination. Load sharing multiple ISLs to connect two
switches was established by a round robin algorithm that assigned the next available ISL as part of
the link to connect a Host Bus Adapter (HBA) and storage. Depending on the fabric event
sequences, multiple HBAs shared an individual ISL. This type of load sharing sometimes caused
the fabric to have congested input/output traffic over the ISLs connecting two switches.
Although FSPF compliant switches ensure fixed routing paths, and guarantee that all frames are
delivered in order, congestion occurs if the aggregation of the stream exceeds the capacity of one of
the ISLs in the path.
For example, Figure 1-1 shows four untrunked ISLs with a maximum capacity of 2Gb/Sec each, for
a maximum throughput of 8Gb/Sec. Due to traffic that is not trunked, the throughput of the four
ISLs is: 1Gb/Sec + 1.5Gb/Sec +.5G + 1Gb/Sec + 1Gb/Sec, giving a total of only 5Gb/Sec, because
two 2Gb/Sec data streams are competing for the same path.
Figure 1-1 Routing without the ISL Trunking Feature
Routing with the ISL Trunking Feature
ISL Trunking ensures that all links are used efficiently, eliminating congestion on one link, while
distributing the load of the links. This feature is designed to significantly reduce traffic congestion.
As shown in Figure 1-2, four ISLs are combined into a single logical ISL with a total capacity of
8Gb/Sec.
The ISL Trunking feature distributes workload across all ISLs in a trunk. Each incoming frame is
sent across the first available ISL. As a result, transient workload peaks for one system or
application are much less likely to impact the performance of other parts of SAN fabric. Because
the full bandwidth of each physical link is available, bandwidth is efficiently allocated.