Brocade Communications Systems A7533A - Brocade 4Gb SAN Switch Base Service manual

53-1000605-01
19 Oct 2007
Access Gateway
Administrator’s Guide
Supporting Fabric OS v6.0.0

Copyright © 2006-2007 Brocade Communications Systems, Inc. All Rights Reserved.
Brocade, the Brocade B-weave logo, Fabric OS, File Lifecycle Manager, MyView, SilkWorm, and StorageX are registered
trademarks and the Brocade B-wing symbol, SAN Health, and Tapestry are trademarks of Brocade Communications Systems,
Inc., in the United States and/or in other countries. FICON is a registered trademark of IBM Corporation in the U.S. and other
countries. All other brands, products, or service names are or may be trademarks or service marks of, and are used to identify,
products or services of their respective owners.
Notice: This document is for informational purposes only and does not set forth any warranty, expressed or implied, concerning
any equipment, equipment feature, or service offered or to be offered by Brocade. Brocade reserves the right to make changes to
this document at any time, without notice, and assumes no responsibility for its use. This informational document describes
features that may not be currently available. Contact a Brocade sales office for information on feature and product availability.
Export of technical data contained in this document may require an export license from the United States government.
The authors and Brocade Communications Systems, Inc. shall have no liability or responsibility to any person or entity with
respect to any loss, cost, liability, or damages arising from the information contained in this book or the computer programs that
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terms applicable to the open source software, and obtain a copy of the programming source code, please visit
http://www.brocade.com/support/oscd.
Brocade Communications Systems, Incorporated
Document History
The following table lists all versions of the Access Gateway Administrator’s Guide.
Corporate Headquarters
Brocade Communications Systems, Inc.
1745 Technology Drive
San Jose, CA 95110
Tel: [phone]
Fax: [phone]
E-mail: inf[email protected]
Asia-Pacific Headquarters
Brocade Communications Singapore Pte. Ltd.
9 Raffles Place
#59-02 Republic Plaza 1
Singapore 048619
Tel: [phone]
Fax: [phone]
Email: [email protected]
European and Latin American Headquarters
Brocade Communications Switzerland Sàrl
Centre Swissair
Tour A - 2ème étage
29, Route de l'Aéroport
Case Postale 105
CH-1215 Genève 15
Switzerland
Tel: [phone]
Fax: [phone]
Email: [email protected]
Document Title Publication Number Summary of Changes Publication Date
Access Gateway Administrator’s Guide 53-1000430-01 First version January 2007
Access Gateway Administrator’s Guide 53-1000633-01 Added support for the 200E 15 Jun 2007
Access Gateway Administrator’s Guide 53-1000605-01 Added support for new policies
and changes to N_Port
mappings.
19 Oct 2007

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Contents
About This Document
How this document is organized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Supported hardware and software . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
What’s new in this document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Document conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Text formatting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Notes, cautions, and warnings . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Key terms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Additional information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Brocade resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Other industry resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Optional Brocade features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Getting technical help. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Document feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
Chapter 1 Introduction to the Brocade Access Gateway
In this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Overview of Brocade Access Gateway . . . . . . . . . . . . . . . . . . . . . . . . . 1
Brocade features in Access Gateway mode . . . . . . . . . . . . . . . . . 2
Access Gateway port types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Comparing FC port configurations . . . . . . . . . . . . . . . . . . . . . . . . 3
Port mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Preferred Secondary N_Port mapping . . . . . . . . . . . . . . . . . . . . . 5
Failover and Failback policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Cold Failover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Port initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Access Gateway policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Path Failover policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Failback policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Port Grouping policy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Automatic port configuration (APC) . . . . . . . . . . . . . . . . . . . . . . 12
Chapter 2 Configuring Access Gateway
In this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Verifying the fabric and edge switch settings . . . . . . . . . . . . . . . . . . 15

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Enabling Access Gateway mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Using the CLI to enable Access Gateway mode . . . . . . . . . . . . . 16
Chapter 3 Disabling Access Gateway Mode
In this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Before you begin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Backing up the Switch Configuration . . . . . . . . . . . . . . . . . . . . . 21
Disabling Access Gateway mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Using the CLI to disable Access Gateway mode. . . . . . . . . . . . .22
Notes on joining the switch to a fabric . . . . . . . . . . . . . . . . . . . . . . . 22
Chapter 4 Managing Ports in Access Gateway mode
In this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Determining the mapping and port status . . . . . . . . . . . . . . . . . . . .25
Displaying the port mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Displaying the port status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Configuring port maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Adding F_Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Removing F_Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Specifying Preferred Secondary N_Ports . . . . . . . . . . . . . . . . . .29
Configuring additional F_Ports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Unlocking N_Port mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Managing policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Path Failover and Failback policies . . . . . . . . . . . . . . . . . . . . . .32
Port Group policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Automatic Port Configuration (APC) . . . . . . . . . . . . . . . . . . . . . . 35
Appendix A Default Port Mapping
Appendix B Compatibility
Appendix C Troubleshooting
Appendix D Access Gateway Commands
Access Gateway commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Index

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About This Document
This document is a procedural guide to help SAN administrators configure and manage Brocade
Access Gateway.
This preface contains the following sections:
•How this document is organized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
•Supported hardware and software. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
•What’s new in this document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
•Document conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
•Key terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
•Additional information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
•Getting technical help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
•Document feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
How this document is organized
The document contains the following topics:
•Chapter 1, “Introduction to the Brocade Access Gateway” describes the Access Gateway
operation.
•Chapter 2, “Configuring Access Gateway” provides the initial setup procedures and fabric
requirement to deploy an Access Gateway solution.
•Chapter 3, “Disabling Access Gateway Mode” provides instructions on disabling Access
Gateway mode so that the switch can be used as a fabric switch.
•Chapter 4, “Managing Ports in Access Gateway mode” provides instructions on changing
N_Ports to F_Ports, mapping F_Ports to N_Ports, and changing various Access Gateway
policies.
•Appendix A, “Default Port Mapping” provides the default N_Port mappings for the different
switches while in Access Gateway mode.
•Appendix B, “Compatibility” provides compatibility information between different devices while
running a switch in Access Gateway mode.
•Appendix C, “Troubleshooting” provides symptoms and troubleshooting tips to resolve issues.
•Appendix D, “Access Gateway Commands” provides the commands for Access Gateway.
The appendixes provide the default mappings, compatibility guidelines, and troubleshooting
assistance.

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Supported hardware and software
In those instances in which procedures or parts of procedures documented here apply to some
switches but not to others, this guide identifies exactly which switches are supported and which are
not.
Although many different software and hardware configurations are tested and supported by
Brocade Communications Systems, Inc. for 6.0.0, documenting all possible configurations and
scenarios is beyond the scope of this document.
The following hardware platforms are supported by this release of Fabric OS v6.0.0 Access
Gateway Administrator’s Guide:
•Brocade 200E switch
•Brocade 4012 switch
•Brocade 4016 switch
•Brocade 4018 switch
•Brocade 4020 switch
•Brocade 4024 switch
What’s new in this document
The following changes have been made since this document was last released:
•Information that was added:
•Support for the 4018 embedded switch
•N_Port grouping policy
•Automatic Port Configuration (APC)
•Preferred Secondary N_Port mapping is an optional secondary failover path for an N_Port
•Information that was changed:
•Path Failback and Failover policies have been enabled to incorporate:
Preferred Secondary N_Port
N_Port grouping
Automatic Port Configuration (APC)
•Enhancements to the Command Line Interface (CLI)
•Information that was deleted:
•none
For further information, refer to the release notes.
Document conventions
This section describes text formatting conventions and important notices formats.

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Text formatting
The narrative-text formatting conventions that are used in this document are as follows:
bold text Identifies command names
Identifies the names of user-manipulated GUI elements
Identifies keywords and operands
Identifies text to enter at the GUI or CLI
italic text Provides emphasis
Identifies variables
Identifies paths and Internet addresses
Identifies document titles
code text Identifies CLI output
Identifies syntax examples
For readability, command names in the narrative portions of this guide are presented in mixed
lettercase: for example, switchShow. In actual examples, command lettercase is often all
lowercase. Otherwise, this manual specifically notes those cases in which a command is case
sensitive. The ficonCupSet and ficonCupShow commands are an exception to this convention.
Notes, cautions, and warnings
The following notices appear in this document.
NOTE
A note provides a tip, emphasizes important information, or provides a reference to related
information.
ATTENTION
An Attention statement indicates potential damage to hardware or data.
CAUTION
A Caution statement alerts you to situations that can be potentially hazardous to you.
DANGER
A Danger statement indicates conditions or situations that can be potentially lethal or extremely
hazardous to you. Safety labels are also attached directly to products to warn of these conditions
or situations.
Key terms
For definitions of SAN-specific terms, visit the Storage Networking Industry Association online
dictionary at: http://www.snia.org/education/dictionary.

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For definitions specific to Brocade and Fibre Channel, see the Brocade Glossary.
The following terms are used in this manual to describe Access Gateway mode and its
components.
Access Gateway (AG) Fabric OS mode for embedded switches that reduces SAN (storage area
network) deployment complexity by leveraging NPIV (N_Port ID virtualization).
E_Port An ISL (Interswitch link) port. A switch port that connects switches together to
form a fabric.
Edge switch A fabric switch that connects host, storage, or other devices, such as Brocade
Access Gateway, to the fabric.
F_Port A fabric port. A switch port that connects a host, HBA (host bus adaptor), or
storage device to the SAN. On Brocade Access Gateway, the F_Port connects
to a host only.
Mapping On the Brocade Access Gateway, the configuration of F_Port to N_Port routes.
N_Port A node port. A Fibre Channel host or storage port in a fabric or point-to-point
connection. On Brocade Access Gateway, the N_Port connects to the edge
switch.
NPIV N_Port ID virtualization. Allows a single Fibre Channel port to appear as
multiple, distinct ports providing separate port identification and security
zoning within the fabric for each operating system image as if each operating
system image had its own unique physical port.
Preferred Secondary N_Port
On the Brocade Access Gateway, the preferred secondary N_Port refers to
the secondary path that and F_Port failovers to if the primary N_Port goes
offline.
Additional information
This section lists additional Brocade and industry-specific documentation that you might find
helpful.
Brocade resources
To get up-to-the-minute information, join Brocade Connect. It’s free! Go to
http://www.brocade.com and click Brocade Connect to register at no cost for a user ID and
password.
For practical discussions about SAN design, implementation, and maintenance, you can obtain
Building SANs with Brocade Fabric Switches through:
http://www.amazon.com
For additional Brocade documentation, visit the Brocade SAN Info Center and click the Resource
Library location:
http://www.brocade.com

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Release notes are available on the Brocade Connect Web site and are also bundled with the Fabric
OS firmware.
Other industry resources
•White papers, online demos, and data sheets are available through the Brocade Web site at
http://www.brocade.com/products/software.jhtml.
•Best practice guides, white papers, data sheets, and other documentation is available through
the Brocade Partner Web site.
For additional resource information, visit the Technical Committee T11 Web site. This Web site
provides interface standards for high-performance and mass storage applications for Fibre
Channel, storage management, and other applications:
http://www.t11.org
For information about the Fibre Channel industry, visit the Fibre Channel Industry Association Web
site:
http://www.fibrechannel.org
Optional Brocade features
For a list of optional Brocade features and descriptions, see the Fabric OS Administrator’s Guide.
Getting technical help
Contact your switch support supplier for hardware, firmware, and software support, including
product repairs and part ordering. To expedite your call, have the following information available:
1. General Information
•Technical Support contract number, if applicable
•Switch model
•Switch operating system version
•Error numbers and messages received
•supportSave command output
•Detailed description of the problem, including the switch or fabric behavior immediately
following the problem, and specific questions
•Description of any troubleshooting steps already performed and the results
•Serial console and Telnet session logs
•Syslog message logs
2. Switch Serial Number
The switch serial number and corresponding bar code are provided on the serial number label,
as shown here.

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:
The serial number label is located as follows:
•Brocade 200E—On the nonport side of the chassis
•Brocade 4100, 4900, and 7500—On the switch ID pull-out tab located inside the chassis
on the port side on the left
•Brocade 5000—On the switch ID pull-out tab located on the bottom of the port side of the
switch
•Brocade 7600—On the bottom of the chassis
•Brocade 48000—Inside the chassis next to the power supply bays
•Brocade DCX—On the bottom right on the port side of the chassis
3. World Wide Name (WWN)
•Use the wwn command to display the switch WWN.
•If you cannot use the wwn command because the switch is inoperable, you can get the
WWN from the same place as the serial number.
Document feedback
Quality is our first concern at Brocade and we have made every effort to ensure the accuracy and
completeness of this document. However, if you find an error or an omission, or you think that a
topic needs further development, we want to hear from you. Forward your feedback to:
[e-mail]
Provide the title and version number of the document and as much detail as possible about your
comment, including the topic heading and page number and your suggestions for improvement.
*FT00X0054E9*
FT00X0054E9

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Chapter
1
Introduction to the Brocade Access Gateway
This chapter describes the functions of Brocade Access Gateway. The Brocade 200E switch and
the Brocade 4012, 4016, 4018, 4020, and 4024 embedded switches running Fabric OS 6.0.0 or
higher support Access Gateway (AG).
In this chapter
•Overview of Brocade Access Gateway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
•Access Gateway port types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
•Port mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
•Failover and Failback policies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
•Cold Failover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
•Port initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
•Access Gateway policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Overview of Brocade Access Gateway
Brocade Access Gateway allows multiple host bus adapters (HBAs) to access the fabric using fewer
physical ports. Access Gateway mode transforms the 200E or an embedded switch into a device
management tool, which is compatible with different types of fabrics, including Brocade, Brocade
Enterprise OS (EOS), and Cisco-based fabrics. For more information on compatibility, refer to the
matrix in Appendix B, “Compatibility”.
When a switch is in Access Gateway mode, it is logically transparent to the host and the fabric.
Brocade Access Gateway mode allows hosts to access the fabric without increasing the number of
switches and simplifies configuration and management in a large fabric by reducing the number of
domain IDs and ports.
Brocade Access Gateway is a device management tool and provides only a subset of Fabric OS
commands. It does not consume critical fabric elements that can inhibit scalability. For example, a
fabric that uses Access Gateways to connect hosts requires fewer domain IDs.
Figure 1 compares a configuration that connects eight hosts to the fabric using Brocade Access
Gateway to the same configuration with standard fabric switches.

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Overview of Brocade Access Gateway
1
FIGURE 1 Access Gateway and fabric switch comparison
The differences between the fabric switch (Fabric OS native mode) and Brocade Access Gateway
are as follows:
•The Fabric OS switch is a part of the fabric; it requires two to four times as many physical ports,
consumes fabric resources, and can connect to a Brocade-based fabric only.
•Brocade Access Gateway is outside the fabric; it reduces the number of switches in the fabric
and the number of required physical ports. You can connect Brocade Access Gateway to either
a Brocade, Brocade EOS, or Cisco-based fabric.
Brocade features in Access Gateway mode
When using a Brocade switch in Access Gateway mode, most features are no longer applicable.
These features include Admin Domains, Advanced Performance Monitoring, direct connection to
SAN target devices, Fibre Channel Arbitrated Loop support, Fabric Manager, FICON, IP over FC, ISL
trunking, extended fabrics, management platform services, name services (SNS), port mirroring,
SMI-S, and zoning. These switch features are available in the default switch mode of operation.
Access Gateway does not support any Secure Fabric OS features. All the security enforcement is
done in the enterprise fabric. The DCC policy in the enterprise fabric should include the N_Port
WWN and the port WWNs of all the HBAs connected to the F_Ports on Access Gateway that are
mapped to that N_Port. In case of a DCC policy violation, the port in the enterprise fabric to which
the F_Ports are connected and the N_Port is mapped to it on Access Gateway are disabled.

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Access Gateway port types 1
Access Gateway port types
Brocade Access Gateway differs from a typical fabric switch because it connects to the fabric using
node ports (N_Ports). Typically fabric switches connect to the enterprise fabric using ISL
(InterSwitch Link) ports, such as an E_Port.
The following defines the Fibre Channel (FC) port terms used in this manual:
•F_Port, fabric port. A switch port that connects a host, HBA, or storage device to the SAN.
•N_Port, node port. A host, HBA, or storage device port that connects to the F_Port of the
fabric switch.
Comparing FC port configurations
Brocade Access Gateway multiplexes host connections to the fabric. It presents an F_Port to the
host and an N_Port to an edge fabric switch. Using N_Port ID virtualization (NPIV), Brocade Access
Gateway allows multiple FC initiators to access the SAN on the same physical port. This reduces
the hardware requirements and management overhead of hosts to the SAN connections.
A fabric switch presents F_Ports (or FL_Ports) to the host and storage devices and presents
E_Ports, TE_Ports, or EX_Ports to other switches in the fabric. A fabric switch consumes SAN
resources, such as domain IDs, and participates in fabric management and zoning distribution. A
fabric switch requires more physical ports than Brocade Access Gateway to connect the same
number of hosts.
Figure 2 compares the types of ports used by the Access Gateway to those used by a typical fabric
switch.
FIGURE 2 Port usage comparison
N_Port F_Port
N_Port
F_Port
N_Port F_Port
Hosts Switch in AG mode
Edge Switch
Fabric
enabled
NPIV
N_Port
F_Port E_Port
E_Port
N_Port
F_Port
Hosts Switch in standard Fabric Switch
E_Port
E_Port
Fabric
Access Gateway Ports
Fabric Switch Ports
default mode

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Port mapping
1
NOTE
The two devices in Figure 2 on page 3 are the same. One switch is in default standard mode and the
other switch is in AG mode.
Table 1 compares port configuration with Access Gateway to a typical fabric switch.
Port mapping
Brocade Access Gateway uses mapping—that is, pre-provisioned routes—to direct traffic from the
hosts to the fabric. When you first enable Access Gateway mode, the F_Ports are mapped to a set
of predefined N_Ports, see Appendix A, “Default Port Mapping”. After the initial setup, you can
manually change the mapping, if required.
TABLE 1 Port Configurations
Port Type Access Gateway Fabric switch
F_Port Yes Connects hosts to Brocade Access
Gateway.
Yes Connects devices, such as hosts, HBAs,
and storage to the fabric.
N_Port Yes Connects Access Gateway to a fabric
switch.
NA N_Ports are not supported.
E_Port NA ISL is not supported.1
1. The switch is logically transparent to the fabric, therefore it does not participate in the SAN as a fabric switch.
Yes Connects the switch to other switches to
form a fabric.

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Port mapping 1
Figure 3 shows a mapping with eight F_Ports evenly mapped to four N_Ports on Brocade Access
Gateway. The N_Ports connect to the same fabric through different edge switches. This example is
also explains mapping, failover, and failback polices.
FIGURE 3 Example F_Port to N_Port mapping
Table 2 describes the mapping and fabric connection shown in Figure 3.
Preferred Secondary N_Port mapping
F_Ports can be mapped to any of the N_Ports on an Access Gateway switch. Each F_Port can be
mapped to only one N_Port as its primary N_Port. When an F_Port is not mapped to any N_Port,
that port is disabled. Optionally, you can specify a Preferred Secondary N_Port for each F_Port. The
Preferred Secondary N_Port, if specified, is used when the primary mapped N_Port fails.
TABLE 2 Example port mapping
Access Gateway Fabric
F_Port N_Port Edge switch F_Port
F_1, F_2 N_1 Switch_A F_A1
F_3, F_4 N_2 Switch_A F_A2
F_5, F_6 N_3 Switch_B F_B1
F_7, F_8 N_4 Switch_B F_B2
N_2
F_A2
Hosts Access Gateway
Edge Switch
Fabric
(Switch_A)
enabled
NPIV
F_4
F_3
F_2
F_1
N_1
F_A1
enabled
NPIV
N_3
F_B1
enabled
NPIV
Host_1
Host_2
Host_3
Host_4
F_5
Host_5
F_6
Host_6
F_7
Host_7
F_8
Host_8
Edge Switch
(Switch_B)
N_4
F_B2
enabled
NPIV

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Failover and Failback policies
When a port is configured as an N_Port, the Failover policy is enabled by default. If a primary
N_Port goes offline because a cable is removed or any other offline event, the F_Ports that are
mapped to the N_Port are disabled. If a Preferred Secondary N_Port is set for any of the F_Ports,
and if those N_Ports are online, these F_Ports will be failed over to their respective Preferred
Secondary N_Port, and then re-enabled. Otherwise, if a Preferred Secondary N_Port is set, but is
not online, those F_Ports are disabled.
Alternatively, if a Preferred Secondary N_Port is not set for any of these F_Ports, these F_Ports
fail-over to other online N_Ports belonging to the same N_Port group, and then re-enables. The
FLOGI and FDISC requests are forwarded from F_Ports through the new N_Port. Failover of F_Ports
to new N_Ports generates a RASLOG message. If multiple N_Ports are available as candidates for
failover, Access Gateway selects one or more N_Ports so that the F_Ports are evenly balanced
across all these N_Ports.
Cold Failover
All F_Ports for an N_Port that goes offline are failed over to other N_Ports. However, if the N_Port
fails to come online after the switch comes online, it triggers cold failover of its F_Ports. If any of
these F_Ports have the Preferred Secondary N_Port set, and if the Preferred Secondary N_Port is
online, those F_Ports fail over to the Preferred Secondary N_Port during cold failover. If a Preferred
Secondary N_Port is set for any of these F_Ports and the Preferred N-Port is not online, then those
F_Ports are disabled. If the Preferred Secondary N_Port is not set for any of these F_Ports, these
F_Ports failover to any N_Ports on the switch so that the F_Ports are evenly balanced across all the
N_Ports belonging to the same N_Port group.
NOTE
Access Gateway incorporates a number of Path Failover and Failback policies to ensure maximum
up time for the servers.
Port initialization
To ensure that all hosts are brought online when Brocade Access Gateway starts up, the ports are
initialized in the following manner:
1. All N_Ports are initialized. During N_Port initialization all the F_Ports are disabled (kept offline).
The ports are enabled or disabled as follows:
•Enabled (online) if the port receives a fabric login event and is connected to an F_Port of
an edge switch that supports NPIV (N_Port ID virtualization).
•Disabled (offline) if the port is not connected to a fabric or is connected to a fabric port
that does not support NPIV.
2. All F_Ports mapped to online N_Ports are enabled.
3. F_Ports mapped to an offline N_Port with the failover policy enabled fail over to an online
N_Port.
4. The host logs in to the fabric as follows:

Access Gateway Administrator’s Guide 7
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Access Gateway policies 1
a. The host sends a FLOGI (fabric login) request.
b. Access Gateway converts the FLOGI request into an FDISC request to the fabric with the
same parameters as the host.
c. The fabric processes the request and sends an FDISC response.
d. Access Gateway converts the FDISC ACC response to the host as an FLOGI ACC using the
same parameters as the fabric.
e. The host receives the response from the fabric.
After ports are initialized, Access Gateway becomes logically transparent to the host and
the fabric, as shown in Figure 4.
FIGURE 4 Host log in request
Access Gateway policies
Access Gateway has four policies available to help you configure and maintain your Access
Gateway environment. The policies listed below are detailed later in this section.
•Path Failover policy enables hosts to automatically remap to an online N_Port within a port
group if the N_Port they are connected to goes offline.
•Failback policy automatically reroutes the F_Ports back to the originally mapped N_Ports if
within a port group as those N_Ports come back online.
•Port Grouping (PG) policy allows you to restrict Failover and Failback to a set of related
N_Ports.
•Automatic Port Configuration (APC) policy enables the switch to automatically detect ports
coming online and enforces a balance ratio of F_Ports to N_Ports.
Path Failover policy
The Brocade Access Gateway Path Failover policy allows hosts to automatically remap to an online
N_Port if the primary N_Port goes offline. The Path Failover policy evenly distributes the F_Ports
that are mapped to an offline N_Port among all the online N_Ports. The Path Failover policy is a
parameter of each N_Port. By default, the Path Failover policy is enabled for all N_Ports.
The following sequence describes how a failover event occurs:
1. An N_Port goes offline.
2. All F_Ports mapped to that N_Port are disabled.
abc
d
e

8Access Gateway Administrator’s Guide
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Access Gateway policies
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3. If the N_Port Failover policy is enabled, and a Preferred Secondary N_Port is specified for the
F_Port and that N_Port is online, the F-Port fails over to respective Preferred Secondary
N_Port, and then re-enables.
NOTE
The Preferred Secondary N_Port is defined per F_Port. For example, if two F_Ports are mapped
to a primary N_Port1, you can define a secondary N_Port for one of those F_Ports and not
define a secondary N_Port for the other F_Port. This is done from a perspective of a server
admin. You must determine whether you want to define a preferred secondary map for each of
the servers or just a subset of the servers.
However, if the Preferred Secondary N_Port is not online, those F_Ports are disabled.
If the Preferred Secondary N_Port is NOT set for any of the F_Ports, these F_Ports will fail-over
to other available N_Ports belonging to the same N_Port Group, and then re-enables.
4. The host establishes a new connection with the fabric.
The Path Failover policy is enabled (or enforced) during power up.
Example: Path Failover Policy
This example shows the failover behavior in a scenario where two fabric ports go offline, one after
the other. Note that in this example we assume that no Preferred Secondary N_Port are set for
any of the F_Ports.
•First the edge switch F_A1 port goes offline, as shown in Figure 5 on page 9 Example 1 (left),
causing the corresponding Access Gateway N_1 port to be disabled.
The ports mapped to N_1 fail over; F_1 fails over to N_2 and F_2 fails over to N_3.
•Next the F_A2 port goes offline, as shown in Figure 5 on page 9 Example 2 (right), causing the
corresponding Access Gateway N_2 port to be disabled.
The ports mapped to N_2 (F_1, F_3, and F_4) fail over to N_3 and N_4. Note that the F_Ports
are evenly distributed to the remaining online N_Ports and that the F_2 did not participate in
the failover event.

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FIGURE 5 Example 1 and 2 Path Failover policy behavior
Failback policy
The Brocade Access Gateway Failback policy automatically reroutes the F_Ports back to the
primary mapped N_Ports as those N_Ports come back online, if failback is enabled for the N_Port.
Only the originally mapped F_Ports fail back. In the case of multiple N_Port failures, only F_Ports
that were mapped to the recovered N_Port experience failback. The remaining F_Ports are not
redistributed among the online N_Ports during the failback; this applies only if the APC is not set.
NOTE
The Failback policy is an N_Port parameter. The Failback policy is enabled by default.
The following sequence describes how a failback event occurs:
1. When an N_Port comes back online, with failBack enabled, the F_Ports that were originally
mapped to it are disabled.
2. The F_Port is reenabled on the primary mapped N_Port.
3. The host establishes a new connection with the fabric.
Example: Failback Policy
In Example 3, the Brocade Access Gateway N_1 remains disabled because the corresponding
F_A1 port is offline. However, N_2 comes back online. See Figure 5 on page 9 for the original
failover scenario.
F_A2
Hosts Access Gateway
Edge Switch
Fabric
(Switch_A)
enabled
NPIV
F_4
F_3
F_2
F_1
N_1
F_A1
enabled
NPIV
N_3
F_B1
enabled
NPIV
Host_1
Host_2
Host_3
Host_4
F_5
Host_5
F_6
Host_6
F_7
Host_7
F_8
Host_8
Edge Switch
(Switch_B)
N_4
F_B2
enabled
NPIV
N_2
Legend
Physical connection
Mapped online
Failover route online
Original mapped route
(offline)
Example 1
F_A2
Hosts Access Gateway
Edge Switch
Fabric
(Switch_A)
enabled
NPIV
F_4
F_3
F_2
F_1
N_1
F_A1
enabled
NPIV
N_3
F_B1
enabled
NPIV
Host_1
Host_2
Host_3
Host_4
F_5
Host_5
F_6
Host_6
F_7
Host_7
F_8
Host_8
Edge Switch
(Switch_B)
N_4
F_B2
enabled
NPIV
Example 2
N_2

10 Access Gateway Administrator’s Guide
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Access Gateway policies
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In Example 3, the ports F_1 and F_2 are mapped to N_1 and continue routing to N_3. Ports F_3
and F_4 were originally mapped to N_2 are disabled and rerouted to N_2, and then enabled.
FIGURE 6 Failback policy behavior
Port Grouping policy
When connecting an AG to multiple fabrics or isolating a subset of servers from other servers, you
might want to group a number of servers and their corresponding fabric ports. You can do this
using the N_Port grouping feature. Port groups cannot be overlapped. This means that an F_Port or
N_Port cannot belong to two different groups.
The Path Failover and Failback policies remain the same within each port group and the Preferred
Secondary N_Port can only specify the N_Ports from the same group. This is why it is
recommended to form groups before defining the preferred secondary path. In FOS v6.0.0 by
default, the Port group policy is enabled. When upgrading to FOS v6.0.0, all the ports on the switch
module belong to a default port group zero identified as pg0. If needed, additional port groups can
be defined.
For example, Figure 7 on page 11 shows an example of pg0. If N_Port1 and 2 are in pg0 and
F_Ports 1-2 are using N_Port1 and N_Port1 goes offline, then F_Ports1-2 are routed through
N_Port2 because N_Port2 is in the same port group, pg0.
F_A2
Hosts Access Gateway
Edge Switch
Fabric
(Switch_A)
enabled
NPIV
F_4
F_3
F_2
F_1
N_1
F_A1
enabled
NPIV
N_3
F_B1
enabled
NPIV
Host_1
Host_2
Host_3
Host_4
F_5
Host_5
F_6
Host_6
F_7
Host_7
F_8
Host_8
Edge Switch
(Switch_B)
N_4
F_B2
enabled
NPIV
N_2
Legend
Physical connection
Mapped online
Failover route online
Original mapped route
(offline)
Example 3