- Index
- Preface
- Product Overview
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- Configuring Ethernet Interfaces
- Configuring VLANs
- Configuring Private VLANs
- Configuring Rapid PVST+
- Configuring Multiple Spanning Tree
- Configuring STP Extensions
- Configuring EtherChannels
- Configuring Access and Trunk Interfaces
- Configuring the MAC Address Table
- Configuring IGMP Snooping
- Configuring Traffic Storm Control
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- Configuring Fibre Channel Interfaces
- Configuring Domain Parameters
- Configuring N-Port Virtualization
- Configuring VSAN Trunking
- Configuring SAN PortChannels
- Configuring and Managing VSANs
- Configuring and Managing Zones
- Distributing Device Alias Services
- Configuring Fibre Channel Routing Services and Protocols
- Managing FLOGI, Name Server, FDMI, and RSCN Databases
- Discovering SCSI Targets
- Advanced Fibre Channel Features and Concepts
- Configuring FC-SP and DHCHAP
- Configuring Port Security
- Configuring Fabric Binding
- Configuring Fabric Configuration Servers
- Configuring Port Tracking
- Configuration Limits
Configuring FCoE
Fibre Channel over Ethernet (FCoE) provides a method of transporting Fibre Channel traffic over a physical Ethernet connection. FCoE requires the underlying Ethernet to be full duplex and to provide lossless behavior for Fibre Channel traffic.
This chapter describes how to configure FCoE and includes the following sections:
Information About FCoE
In Cisco Nexus 5000 Series switches, FCoE is supported on all 10-Gigabit Ethernet interfaces.
To use FCoE, the switch must be directly connected to the server and the server port must terminate the Ethernet with a converged network adapter.
This section includes the following topics:
- Licensing Requirements
- Converged Network Adapters
- DCBX Capabilities
- DCE Bridging Capability Exchange Protocol
- DCBX Feature Negotiation
- Ethernet Frame Formats
Licensing Requirements
On Cisco Nexus 5000 Series switches, FCoE capability is included in the Storage Protocol Services License.
Converged Network Adapters
The following types of converged network adapters (CNAs) are available:
– Works with the existing FC HBA driver and LAN NIC driver in the server.
– Server operating system view of the network is unchanged; the CNA presents a SAN interface and a LAN interface to the operating system.
– Runs on existing 10-Gigabit Ethernet adapters.
FCoE offers a number of optional capabilities. The available capabilities and their configurable values are negotiated between the switch and the adapter. To accomplish this, the adapter and the switch exchange information using the Data Center Bridging Exchange Protocol (DCBX).
To reduce configuration errors and simplify administration. you can configure the switch to distribute the configuration data to all the connected adapters.
DCBX Capabilities
The DCBX capabilities supported by Cisco Nexus 5000 Series switches are described in the following topics:
FCoE
By default, each Ethernet interface attempts to enable FCoE capability by advertising the capability to the adapter.
If the FCoE negotiation fails, you can configure the switch to disable FCoE or to force-enable FCoE for this interface.
Priority Flow Control
The priority flow control (PFC) capability allows you to apply pause functionality to specific classes of traffic. PFC decides whether to apply pause based on the IEEE 802.1p CoS value. When the switch enables PFC, it configures the connected adapter to apply the pause functionality to packets with specific CoS values.
By default, the switch negotiates to enable the PFC capability. If the negotiation succeeds, PFC is enabled and link-level flow control remains disabled (regardless of its configuration settings).
If the PFC negotiation fails, you can either force PFC to be enabled on the interface or you can enable IEEE 802.x link-level flow control.
Link-level flow control can be enabled on the interface only if PFC is not enabled. For additional information about link-level flow control, see the “Link-Level Flow Control” section.
Logical Link Up/Down
On a native Fibre Channel link, some configuration actions (such as changing the VSAN) require you to reset the interface status. The switch achieves the reset by disabling the interface, and then immediately reenabling the interface.
If an Ethernet link is providing FCoE service, the physical link should not be reset because this action is disruptive to all traffic on the link.
The logical link up/down feature provides the ability to reset an individual virtual link. The switch sends a DCBX message to request the adapter to reset only the virtual Fibre Channel interface.
Note If the adapter does not support the logical link level up/down feature, the adapter resets the physical link. In this case, all traffic on the Ethernet interface is disrupted.
DCE Bridging Capability Exchange Protocol
DCBX protocol is an extension of the Link Layer Discovery Protocol (LLDP). DCBX end points exchange request and acknowledgment messages. For flexibility, parameters are coded in a type-length-value (TLV) format.
DCBX runs on the physical Ethernet link between the Cisco Nexus 5000 Series switch and the converged network adapter on the server. By default, DCBX is enabled on Ethernet interfaces. When an Ethernet interface is brought up, the switch automatically starts to communicate with the adapter.
During normal operation of FCoE between the switch and the adapter, the DCBX protocol provides link-error detection.
DCBX is also used to negotiate capabilities between the switch and the adapter and to send configuration values to the adapter.
Adapters connected to a Cisco Nexus 5000 Series switch are programmed to accept the configuration values sent by the switch, allowing the switch to distribute configuration values to all attached adapters. The capability reduces the possibility of configuration error and simplifies administration of the adapters.
The switch provides a manual configuration override for each parameter negotiated using DCBX. The override takes effect if the adapter does not support DCBX, or if the adapter does not support the specific capability requested by the switch.
DCBX Feature Negotiation
The switch and adapter exchange capability information and configuration values. The Cisco Nexus 5000 Series switches support the following capabilities:
If the adapter supports FCoE capability, the switch sends the IEEE 802.1p CoS value to be used with FCoE packets.
If the adapter supports PFC, the switch sends the IEEE 802.1p CoS values to be enabled with PFC.
The following rules determine whether the negotiation results in a capability being enabled:
- If a capability and its configuration values match between the switch and the adapter, the feature is enabled.
- If the capability matches, but the configuration values do not match:
– If the adapter is configured to accept the switch configuration value, the capability is enabled using the switch value.
– If the adapter is not configured to accept the switch configuration value, the capability remains disabled.
- If the adapter does not support the DCBX capability, the capability remains disabled.
- If the adapter does not implement DCBX, all capabilities remain disabled.
Note The Cisco Nexus 5000 Series switch provides CLI commands to manually override the results of the negotiation with the adapter. On a per-interface basis, you can force capabilities to be enabled or disabled. For additional information, see the “Configuring FCoE” section.
Ethernet Frame Formats
Ethernet frames sent by the switch to the adapter may include the IEEE 802.1Q tag. This tag includes a field for the CoS value used by PFC. The IEEE 802.1Q tag also includes a VLAN field, currently not used by the Cisco Nexus 5000 Series switch.
The switch will always accept tagged or untagged frames from the adapter.
If the FCoE capability is enabled between the switch and the adapter:
The CoS field is set to the CoS value of the associated system class. For additional information, see the “System Classes” section.
If the FCoE capability is disabled between the switch and the adapter:
Configuring FCoE
This section contains the following topics:
- Enabling FCoE
- Enabling FCoE on Ethernet Interfaces
- Configuring Priority Flow Control
- Configuring IEEE 802.3x Link-Level Flow Control
Enabling FCoE
You need to enable the FCoE capability after the FC_FEATURES_PKG is installed. To enable FCoE, perform this task:
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The following example shows how to enable FCoE on the switch:
switch(config)# feature fcoe
switch(config)# 2008 Nov 11 20:43:38 switch %$ VDC-1 %$ %PFMA-2-FC_LICENSE_DESIRED: FCoE/FC feature will be enabled after the configuration is saved followed by a reboot
Note After you enable the FCoE capability, you must reboot the Cisco Nexus 5000 Series switch before you can use the features.
Enabling FCoE on Ethernet Interfaces
By default, 10-Gigabit Ethernet interfaces negotiate FCoE capability with the adapter. You can override the negotiation result by force-enabling the FCoE capability. To force-enable the FCoE capability, perform this task:
The following example shows how to force-enable FCoE for an Ethernet interface:
To disable the FCoE capability, perform this task:
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This example shows how to disable FCoE for an Ethernet interface:
The fcoe command can only be applied to a physical Ethernet interface.
Configuring Priority Flow Control
By default, the Ethernet interfaces negotiate PFC capability with the adapter. You can override the negotiation result by force-enabling the PFC capability.
To force-enable the PFC capability, perform this task:
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Sets PFC mode for the selected interface. |
The following example shows how to force-enable PFC on an interface:
To disable PFC capability for this interface, perform this task:
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Configuring IEEE 802.3x Link-Level Flow Control
By default, link-level flow control capability on Ethernet interfaces is disabled. Only enable the link-level flow control capability if PFC is disabled on the interface.
To configure link-level flow control, see the “Configuring IEEE 802.3x Link-Level Flow Control” section.
Configuring LLDP
This section shows how to configure LLDP both globally and on individual interfaces. This section includes the following topics:
Configuring Global LLDP Commands
You can set global LLDP settings. These settings include the length of time before discarding LLDP information received from peers, the length of time to wait before performing LLDP initialization on any interface, and the rate at which LLDP packets are sent.
To configure LLDP settings, perform this task:
The following example shows how to set LLDP timer option to 15 seconds:
To reset LLDP settings, perform this task:
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Configuring Interface LLDP Commands
To configure the LLDP feature for a physical Ethernet interface, perform this task:
The following example shows how to set an interface to transmit LLDP packets:
switch(config)# interface ethernet 1/2
switch(config-if)# lldp transmit
The following example shows how to configure an interface to disable LLDP:
switch(config)# interface ethernet 1/2
switch(config-if)# no lldp transmit
switch(config-if)# no lldp receive
You can only apply this command to a physical Ethernet interface.
Verifying FCoE Configuration
To verify FCoE configuration information, perform one of these tasks:
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The following example shows how to verify that the FCoE capability is enabled:
FCoE/FC feature is desired.
The following example shows how to display LLDP interface information:
tx_enabled: TRUE
rx_enabled: TRUE
dcbx_enabled: TRUE
Port MAC address: 00:0d:ec:a3:5f:48
Remote Peers Information
No remote peers exist
The following example shows how to display LLDP neighbor information:
The following example shows how to display LLDP timer information:
LLDP Timers
holdtime 120 seconds
reinit 2 seconds
msg_tx_interval 30 seconds
The following example shows how to display LLDP counters: