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Interfaces Configuration Guide, Cisco DCNM for SAN, Release 5.x
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Index
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New and Changed Information
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Preface
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Interfaces Overview
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Configuring Interfaces
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Configuring Ethernet Interfaces
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Configuring Virtual Interfaces
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Configuring Fibre Channel Interfaces
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Configuring Interface Buffers
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Configuring Trunking
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Configuring Port Channels
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Configuring N Port Virtualization
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Configuring FlexAttach Virtual pWWN
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Feedback
Table Of Contents
Generation 1 Interface Configuration Guidelines
Private Loop Configuration Guidelines
VSAN Interface Configuration Guidelines
Common Interface Configuration
Configuring Fibre Channel Interfaces
Setting the Interface Administrative State
Configuring Port Administrative Speeds
Configuring the Interface Description
Configuring Switch Port Attribute Default Values
Configuring Management Interfaces
Verifying Interfaces Configuration
Obtaining Interface Statistics
Displaying SFP Transmitter Types
Configuring Interfaces
This chapter describes the basic interface configuration to get your switch up and running.
This chapter includes the following topics:
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Verifying Interfaces Configuration
Information About Interfaces
The main function of a switch is to relay frames from one data link to another. To relay the frames, the characteristics of the interfaces through which the frames are received and sent must be defined. The configured interfaces can be Fibre Channel interfaces, Gigabit Ethernet interfaces, the management interface (mgmt0), or VSAN interfaces.
This section includes the following topics:
Interface Description
For the Fibre Channel interfaces, you can configure the description parameter to provide a recognizable name for the interface. Using a unique name for each interface allows you to quickly identify the interface when you are looking at a listing of multiple interfaces. You can also use the description to identify the traffic or the use for that interface.
Interface Modes
Each physical Fibre Channel interface in a switch may operate in one of several port modes: E port, F port, FL port, TL port, TE port, SD port, ST port, and B port (see Figure 2-1). Besides these modes, each interface may be configured in auto or Fx port modes. These two modes determine the port type during interface initialization.
Figure 2-1 Cisco MDS 9000 Family Switch Port Modes
Note
Each interface has an associated administrative configuration and an operational status:
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Each interface is briefly described in the sections that follow.
E Port
In expansion port (E port) mode, an interface functions as a fabric expansion port. This port may be connected to another E port to create an Inter-Switch Link (ISL) between two switches. E ports carry frames between switches for configuration and fabric management. They serve as a conduit between switches for frames destined to remote N ports and NL ports. E ports support class 2, class 3, and class F service.
An E port connected to another switch may also be configured to form a PortChannel (see Chapter 8, "Configuring PortChannels").
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F Port
In fabric port (F port) mode, an interface functions as a fabric port. This port may be connected to a peripheral device (host or disk) operating as an N port. An F port can be attached to only one N port. F ports support class 2 and class 3 service.
FL Port
In fabric loop port (FL port) mode, an interface functions as a fabric loop port. This port may be connected to one or more NL ports (including FL ports in other switches) to form a public arbitrated loop. If more than one FL port is detected on the arbitrated loop during initialization, only one FL port becomes operational and the other FL ports enter nonparticipating mode. FL ports support class 2 and class 3 service.
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NP Ports
An NP port is a port on a device that is in NPV mode and connected to the core switch via an F port. NP ports function like N ports except that in addition to providing N port operations, they also function as proxies for multiple, physical N ports.
Note
For more details about NP ports and NPV, see Chapter 9, "Configuring N Port Virtualization."
TL Port
In translative loop port (TL port) mode, an interface functions as a translative loop port. It may be connected to one or more private loop devices (NL ports). TL ports are specific to Cisco MDS 9000 Family switches and have similar properties as FL ports. TL ports enable communication between a private loop device and one of the following devices:
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TL ports support class 2 and class 3 services.
Private loop devices refer to legacy devices that reside on arbitrated loops. These devices are not aware of a switch fabric because they only communicate with devices on the same physical loop (see the "TL Port ALPA Caches" section).
Tip
Note
TE Port
In trunking E port (TE port) mode, an interface functions as a trunking expansion port. It may be connected to another TE port to create an extended ISL (EISL) between two switches. TE ports are specific to Cisco MDS 9000 Family switches. They expand the functionality of E ports to support the following:
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In TE port mode, all frames are transmitted in EISL frame format, which contains VSAN information. Interconnected switches use the VSAN ID to multiplex traffic from one or more VSANs across the same physical link. This feature is referred to as trunking in the Cisco MDS 9000 Family switches (see Chapter 7, "Configuring Trunking"). TE ports support class 2, class 3, and class F service.
TF Port
In trunking F port (TF port) mode, an interface functions as a trunking expansion port. It may be connected to another trunked N port (TN port) or trunked NP port (TNP port) to create a link between a core switch and an NPV switch or an HBA to carry tagged frames. TF ports are specific to Cisco MDS 9000 Family switches. They expand the functionality of F ports to support VSAN trunking.
In TF port mode, all frames are transmitted in EISL frame format, which contains VSAN information. Interconnected switches use the VSAN ID to multiplex traffic from one or more VSANs across the same physical link. This feature is referred to as trunking in the Cisco MDS 9000 Family (see Chapter 7, "Configuring Trunking"). TF ports support class 2, class 3, and class F service.
TNP Port
In trunking NP port (TNP port) mode, an interface functions as a trunking expansion port. It may be connected to a trunked F port (TF port) to create a link to a core NPIV switch from an NPV switch to carry tagged frames.
SD Port
In SPAN destination port (SD port) mode, an interface functions as a switched port analyzer (SPAN). The SPAN feature is specific to switches in the Cisco MDS 9000 Family. It monitors network traffic that passes though a Fibre Channel interface. This monitoring is done using a standard Fibre Channel analyzer (or a similar switch probe) that is attached to an SD port. SD ports do not receive frames, they only transmit a copy of the source traffic. The SPAN feature is nonintrusive and does not affect switching of network traffic for any SPAN source ports (see the Cisco MDS 9000 Family NX-OS System Management Configuration Guide).
ST Port
In the SPAN tunnel port (ST port) mode, an interface functions as an entry point port in the source switch for the RSPAN Fibre Channel tunnel. The ST port mode and the remote SPAN (RSPAN) feature are specific to switches in the Cisco MDS 9000 Family. When configured in ST port mode, the interface cannot be attached to any device, and thus cannot be used for normal Fibre Channel traffic (see the Cisco MDS 9000 Family NX-OS System Management Configuration Guide).
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Fx Port
Interfaces configured as Fx ports can operate in either F port or FL port mode. The Fx port mode is determined during interface initialization depending on the attached N port or NL port. This administrative configuration disallows interfaces to operate in any other mode—for example, preventing an interface to connect to another switch.
B Port
While E ports typically interconnect Fibre Channel switches, some SAN extender devices, such as the Cisco PA-FC-1G Fibre Channel port adapter, implement a bridge port (B port) model to connect geographically dispersed fabrics. This model uses B ports as described in the T11 Standard FC-BB-2.
If an FCIP peer is a SAN extender device that only supports Fibre Channel B ports, you need to enable the B port mode for the FCIP link. When a B port is enabled, the E port functionality is also enabled and they coexist. If the B port is disabled, the E port functionality remains enabled (see the Cisco MDS 9000 Family NX-OS IP Services Configuration Guide).
Auto Mode
Interfaces configured in auto mode can operate in one of the following modes: F port, FL port, E port, TE port, or TF port. The port mode is determined during interface initialization. For example, if the interface is connected to a node (host or disk), it operates in F port or FL port mode depending on the N port or NL port mode. If the interface is attached to a third-party switch, it operates in E port mode. If the interface is attached to another switch in the Cisco MDS 9000 Family, it may become operational in TE port mode (see Chapter 7, "Configuring Trunking").
TL ports and SD ports are not determined during initialization and are administratively configured.
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Interface States
The interface state depends on the administrative configuration of the interface and the dynamic state of the physical link.
Administrative States
The administrative state refers to the administrative configuration of the interface as described in Table 2-1.
Operational States
The operational state indicates the current operational state of the interface as described in Table 2-2.
Reason Codes
Reason codes are dependent on the operational state of the interface as described in Table 2-3.
Table 2-3 Reason Codes for Interface States
Up
Up
None.
Down
Down
Administratively down—If you administratively configure an interface as down, you disable the interface. No traffic is received or transmitted.
Up
Down
See Table 2-4.
Note
If the administrative state is up and the operational state is down, the reason code differs based on the nonoperational reason code as described in Table 2-4.
Graceful Shutdown
Interfaces on a port are shut down by default (unless you modified the initial configuration).
The Cisco NX-OS software implicitly performs a graceful shutdown in response to either of the following actions for interfaces operating in the E port mode:
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A graceful shutdown ensures that no frames are lost when the interface is shutting down. When a shutdown is triggered either by you or the Cisco NX-OS software, the switches connected to the shutdown link coordinate with each other to ensure that all frames in the ports are safely sent through the link before shutting down. This enhancement reduces the chance of frame loss.
A graceful shutdown is not possible in the following situations:
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Port Administrative Speeds
By default, the port administrative speed for an interface is automatically calculated by the switch.
For internal ports on the Cisco Fabric Switch for HP c_Class BladeSystem and Cisco Fabric Switch for IBM BladeCenter, a port speed of 1 Gbps is not supported. Auto-negotiation is supported between 2 Gbps and 4 Gbps only. Also, if the BladeCenter is a T chassis, then port speeds are fixed at 2 Gbps and auto-negotiation is not enabled.
Autosensing
Autosensing speed is enabled on all 4-Gbps and 8-Gbps switching module interfaces by default. This configuration enables the interfaces to operate at speeds of 1 Gbps, 2 Gbps, or 4 Gbps on the 4-Gbps switching modules, and 8 Gbps on the 8-Gbps switching modules. When autosensing is enabled for an interface operating in dedicated rate mode, 4 Gbps of bandwidth is reserved, even if the port negotiates at an operating speed of 1 Gbps or 2 Gbps.
To avoid wasting unused bandwidth on 48-port and 24-port 4-Gbps and 8-Gbps Fibre Channel switching modules, you can specify that only 2 Gbps of required bandwidth be reserved, not the default of 4 Gbps or 8 Gbps. This feature shares the unused bandwidth within the port group provided that it does not exceed the rate limit configuration for the port. You can also use this feature for shared rate ports that are configured for autosensing.
Tip
You can set the frame format to EISL for all frames transmitted by the interface in SD port mode. If you sent the frame encapsulation to EISL, all outgoing frames are transmitted in the EISL frame format, regardless of the SPAN sources. See the Cisco MDS 9000 Family NX-OS System Management Configuration Guide.
Refer to the Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide to configure frame encapsulation on an interface.
Beacon LEDs
Figure 2-2 displays the status, link, and speed LEDs in a 16-port switching module.
Figure 2-2 Cisco MDS 9000 Family Switch Interface Modes
Status LED1
Link LEDs1 and speed LEDs2
1/2-Gbps Fibre Channel port group
Asset tag3
1 See the Cisco MDS 9000 Family NX-OS Fundamentals Configuration Guide.
2 See the "Speed LEDs" section.
3 Refer to the Cisco MDS 9000 Family hardware installation guide for your platform.
Speed LEDs
Each port has one link LED on the left and one speed LED on the right.
The speed LED displays the speed of the port interface:
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The speed LED also displays if the beacon mode is enabled or disabled:
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Bit Error Thresholds
The bit error rate threshold is used by the switch to detect an increased error rate before performance degradation seriously affects traffic.
The bit errors can occur for the following reasons:
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A bit error rate threshold is detected when 15 error bursts occur in a 5-minute period. By default, the switch disables the interface when the threshold is reached. You can enter a shutdown and no shutdown command sequence to re-enable the interface.
You can configure the switch to not disable an interface when the threshold is crossed. By default, the threshold disables the interface.
SFP Transmitter Types
The small form-factor pluggable (SFP) hardware transmitters are identified by their acronyms when displayed. Table 2-5 defines the acronyms used for SFPs.
See the "Displaying SFP Transmitter Types" section.
TL Ports
Private loop devices refer to legacy devices that reside on arbitrated loops. These devices are not aware of a switch fabric because they only communicate with devices on the same physical loop. The legacy devices are used in Fibre Channel networks, and devices outside the loop may need to communicate with them. The communication functionality is provided through TL ports. See the "Interface Modes" section.
TL port mode is not supported on the following hardware:
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Table 2-6 lists the TL port translations supported in Cisco MDS 9000 Family switches.
Figure 2-3 shows examples of TL port translation support.
Figure 2-3 TL Port Translation Support Examples
TL Port ALPA Caches
Although TL ports cannot be automatically configured, you can manually configure entries in arbitrated loop physical address (ALPA) caches. Generally, ALPA cache entries are automatically populated when an ALPA is assigned to a device. Each device is identified by its port world wide name (pWWN). When a device is allocated an ALPA, an entry for that device is automatically created in the ALPA cache.
A cache contains entries for recently allocated ALPA values. These caches are maintained on various TL ports. If a device already has an ALPA, the Cisco NX-OS software attempts to allocate the same ALPA to the device each time. The ALPA cache is maintained in persistent storage and saves information across switch reboots. The maximum cache size is 1000 entries. If the cache is full, and a new ALPA is allocated, the Cisco NX-OS software discards an inactive cache entry (if available) to make space for the new entry. See the "TL Port" section for more information on TL ports.
Refer to the Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide to manage the TL Port ALPA cache.
Port Guard
The port guard feature is intended for use in environments where the system and application environment does not adapt quickly and efficiently to a port going down and back up, or to a port rapidly cycling up and down, which can happen in some failure modes. For example, if a system takes five seconds to stabilize after a port goes down, but the port is going up and down once a second, this might ultimately cause a more severe failure in the fabric.
The port guard feature gives the SAN administrator the ability to prevent this issue from occurring in environments that are vulnerable to these problems. The port can be configured to stay down after the first failure, or after specified number of failures in a specified time period. This allows the SAN administrator to intervene and control the recovery, avoiding any problems caused by the cycling.
Using the port guard feature, you can restrict the number of error reports and bring a malfunctioning port to down state dynamically. A port can be configured to go into error-disabled state for specific types of failures.
A general link failure caused by link-down is the superset of all other causes. The sum of the number of all other causes equals to the number of link-down link failures. This means a port is brought to down state when it reaches the maximum number of allowed link failures or the number of specific causes.
The causes of link failure can be any of the following:
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Port Monitor
Port monitor helps to monitor the performance and the status of ports and generate alerts when problems occur. You can configure the thresholds for various counters and trigger an event when the values cross the threshold settings.
The default port monitor policy has the following threshold values:
Port Group Monitor
Each line card or module has a predefined set of ports which share the same backplane bandwidth called port groups. While oversubscription is a feature, the port group monitor feature helps to monitor the spine bandwidth utilization. An alarm syslog is generated so that you can provision the ports across port groups evenly to manage the oversubscription better.
When the port group monitor feature is enabled and a policy consisting of polling interval in seconds, and the raising and falling thresholds in percentage are specified, port group monitor generates a syslog if a port group traffic goes above the specified percentage of the maximum supported bandwidth for that port group (for rx and for tx) and another syslog if the value falls below the specified threshold.
The default port group policy has the following threshold values:
RX Performance
Delta
60
80
20
TX Performance
Delta
60
80
20
Management Interfaces
You can remotely configure the switch through the management interface (mgmt0). To configure a connection on the mgmt0 interface, you must configure either the IP version 4 (IPv4) parameters (IP address, subnet mask, and default gateway) or the IP version 6 (IPv6) parameters so that the switch is reachable.
Before you begin to configure the management interface manually, obtain the switch's IPv4 address and subnet mask, or the IPv6 address.
The management port (mgmt0) is autosensing and operates in full-duplex mode at a speed of 10/100/1000 Mbps. Autosensing supports both the speed and the duplex mode. On a Supervisor-1 module, the default speed is 100 Mbps and the default duplex mode is auto. On a Supervisor-2 module, the default speed is auto and the default duplex mode is auto.
Note
VSAN Interfaces
VSANs apply to Fibre Channel fabrics and enable you to configure multiple isolated SAN topologies within the same physical infrastructure. You can create an IP interface on top of a VSAN and then use this interface to send frames to this VSAN. To use this feature, you must configure the IP address for this VSAN. VSAN interfaces cannot be created for nonexisting VSANs.
Prerequisites for Interfaces
Before you begin configuring the interfaces, ensure that the modules in the chassis are functioning as designed. For information about verifying the module status, refer to the Cisco NX-OS Fundamentals Configuration Guide.
Guidelines and Limitations
This section includes the following topics:
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Generation 1 Interface Configuration Guidelines
The Generation 1 interfaces configuration guidelines apply to the following hardware:
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When configuring these host-optimized ports, the following port mode guidelines apply:
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Private Loop Configuration Guidelines
Follow these guidelines when configuring private loops:
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VSAN Interface Configuration Guidelines
Follow these guidelines when creating or deleting VSAN interfaces:
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Default Settings
Table 2-7 lists the default settings for interface parameters.
Configuring Interfaces
This section includes the following topics:
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For more information on configuring mgmt0 interfaces, refer to the Cisco MDS 9000 Family NX-OS Fundamentals Configuration Guide and Cisco MDS 9000 Family NX-OS IP Services Configuration Guide.
For more information on configuring Gigabit Ethernet interfaces, see the Cisco MDS 9000 Family NX-OS IP Services Configuration Guide.
Common Interface Configuration
Some configuration settings are similar for Fibre Channel, management, and VSAN interfaces. You can configure interfaces from DCNM-SAN by expanding Switches > FC Interfaces and selecting either the Physical or Logical interface type from the Physical Attributes pane.
Configuring Fibre Channel Interfaces
For the Cisco Fabric Switch for HP c-Class BladeSystem and the Cisco Fabric Switch for IBM BladeCenter, you can configure a range of interfaces among internal ports or external ports, but you cannot mix both interface types within the same range. For example, "bay 1-10, bay 12" or "ext 0, ext 15-18" are valid ranges, but "bay 1-5, ext 15-17" is not.
Setting the Interface Administrative State
Detailed Steps
To disable or enable an interface using DCNM-SAN, follow these steps:
Step 1
Step 2
Step 3
You see the drop-down box.
Step 4
Step 5
Step 6
Configuring Interface Modes
Detailed Steps
To configure the interface mode using DCNM-SAN, follow these steps:
Step 1
You see the interface configuration in the Information pane.
Step 2
Step 3
Step 4
Step 5
Configuring Port Administrative Speeds
Restrictions
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Detailed Steps
To configure the administrative speed of the interface using DCNM-SAN, follow these steps:
Step 1
You see the interface configuration in the Information pane.
Step 2
Step 3
The number indicates the speed in megabits per second (Mbps). You can set the speed to 1-Gbps, 2-Gbps, 4-Gbps, 8-Gbps, autoMax2G, autoMax4G, or auto (default).
Note
Step 4
Configuring Port Speed Group
Detailed Steps
To configure the administrative speed of the interface using DCNM-SAN, follow these steps:
Step 1
You see the interface configuration in the Information pane.
Step 2
Step 3
You can select any of the speed groups from the menu list—notApplicable, tenG, oneTwoFourEightG, or twoFourEightSixteenG.
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Step 4
Configuring the Interface Description
The interface description can be any alphanumeric string.
Specifying a Port Owner
Using the port owner feature, you can specify the owner of a port and the purpose for which a port is used so that the other administrators are informed.
Note
Detailed Steps
To specify or remove the port owner using DCNM-SAN, follow these steps:
Step 1
You see the interface configuration in the Information pane.
Step 2
Step 3
To specify or remove the port owner using Device Manager, follow these steps:
Step 1
Step 2
Step 3
Step 4
Configuring Beacon Mode
By default, the beacon mode is disabled on all switches. The beacon mode is indicated by a flashing green light that helps you identify the physical location of the specified interface. Configuring the beacon mode has no effect on the operation of the interface.
Detailed Steps
To enable beacon mode for a specified interface or range of interfaces using DCNM-SAN, follow these steps:
Step 1
You see the interface configuration in the Information pane.
Step 2
Step 3
Troubleshooting Tips
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Disabling Bit Error Threshold
Note
Configuring Switch Port Attribute Default Values
You can configure attribute default values for various switch port attributes. These attributes will be applied globally to all future switch port configurations, even if you do not individually specify them at that time.
Configuring TL Ports
Private loops require setting the interface mode to TL.
Detailed Steps
To configure the TL interface mode using DCNM-SAN, follow these steps:
Step 1
Step 2
Step 3
Step 4
Step 5
Configuring Port Guard
To enable port guard using DCNM-SAN, follow these steps:
Step 1
You see the interfaces listed in the Information pane.
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
Step 8
Step 9
Step 10
To enable port guard for single or multiple interfaces using Device Manager, follow these steps:
Step 1
You see the FC Interfaces listed.
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
Step 8
Step 9
Troubleshooting Tips
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Configuring Management Interfaces
Detailed Steps
To configure the management interface using DCNM-SAN, follow these steps:
Step 1
Step 2
You see the interface configuration in the Information pane.
Step 3
Step 4
Step 5
Step 6
Creating VSAN Interfaces
Detailed Steps
To create a VSAN interface using DCNM-SAN, follow these steps:
Step 1
Step 2
You see the Create Interface dialog box.
Step 3
Note
Step 4
Step 5
Verifying Interfaces Configuration
This section includes the following topics:
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Displaying the Owned Ports
Detailed Steps
To display the interfaces owned using Device Manager, follow these steps:
Step 1
Step 2
Obtaining Interface Statistics
You can use DCNM-SAN or Device Manager to collect interface statistics on any switch. These statistics are collected at intervals that you can set.
Note
Detailed Steps
To obtain and display interface counters using Device Manager, follow these steps:
Step 1
Select any of the Interfaces that are displayed. For example, Virtual FC Enabled.
Step 2
Step 3
Step 4
Step 5
Step 6
Displaying SFP Transmitter Types
Detailed Steps
To show the SFP types for an interface using DCNM-SAN, follow these steps:
Step 1
Step 2
Monitoring a Port Group
Detailed Steps
To monitor a particular group using Device Manager, follow these steps:
Step 1
The Check Oversubscription table is displayed.
Step 2
The Device Manager displays the monitoring table of the selected group with counters on each interval and displays the line chart automatically. From the Monitoring table, you can also choose the Bar chart icon to view the selected group as bar charts.
