Cisco Nexus 5000 Series NX-OS Software Configuration Guide

Fibre Channel over Ethernet

Fibre Channel over Ethernet (FCoE) provides a method of encapsulating Fibre Channel traffic over a physical Ethernet link. FCoE frames use a unique Ethertype so that FCoE traffic and standard Ethernet traffic can be carried on the same link.

Fibre Channel traffic requires a lossless transport layer. Native Fibre Channel implements lossless service using a buffer-to-buffer credit system. For FCoE traffic, the Ethernet link must provide lossless service.

Ethernet links on Cisco Nexus 5000 Series switches provide two mechanisms to ensure lossless transport for FCoE traffic: link-level flow control and priority flow control.

IEEE 802.3x link-level flow control allows a congested receiver to signal the far end to pause the data transmission for a short period of time. The pause functionality is applied to all the traffic on the link.

The priority flow control (PFC) feature applies pause functionality to specific classes of traffic on the Ethernet link. For example, PFC can provide lossless service for the FCoE traffic, and best-effort service for the standard Ethernet traffic. PFC can provide different levels of service to specific classes of Ethernet traffic (using IEEE 802.1p traffic classes).

I/O Consolidation

I/O consolidation (IOC) allows a single network technology to carry IP, SAN and IPC traffic.

FCoE enables an evolutionary approach to IOC. The upper Fibre Channel layers are unchanged, so the Fibre Channel operational model is maintained. FCoE network management and configuration is similar to a native Fibre Channel network.

Cisco Nexus 5000 Series switches use FCoE to carry Fibre Channel and Ethernet traffic on the same physical Ethernet connection between the switch and the server. At the server, the connection terminates to a converged network adapter (CNA). The adapter presents two interfaces to the server’s operating system (OS): one Ethernet NIC interface and one Fibre Channel HBA interface. The server OS is not aware of the FCoE encapsulation (See Figure 1-1)

At the switch, the incoming Ethernet port separates the Ethernet and Fibre Channel traffic (using Ethertype to differentiate the frames). Ethernet frames and Fibre Channel frames are switched to their respective network-side interfaces.

Cisco Nexus 5000 Series switches provide quality of service (QoS) capabilities to ensure lossless service across the switch for Fibre Channel traffic. Best-effort service can be applied to all of the Ethernet traffic or specific classes of Ethernet traffic can be configured with different QoS levels.

Figure 1-1 I/O Consolidation

Virtual Interfaces

When FCoE is enabled, a physical Ethernet cable carries traffic for a logical Fibre Channel connection.

The Cisco Nexus 5000 Series switch uses virtual interfaces to represent the logical Fibre Channel connections. For configuration purposes, virtual Fibre Channel interfaces are implemented as Layer 2 subinterfaces of the physical Ethernet interface.

Ethernet features (such as link debounce timer and VLAN membership) are configured on the physical Ethernet interface. Logical Fibre Channel features (such as VSAN membership) are configured on the virtual Fibre Channel interfaces.

Chassis

The Nexus 5010 switch is a 1 RU chassis and the Nexus 5020 switch is a 2 RU chassis designed for rack mounting. The chassis supports redundant fans and power supplies.

The Cisco Nexus 5000 Series switching fabric is low latency, nonblocking and supports Ethernet frame sizes from 64 to 9216 bytes.

Expansion Modules

The Nexus 5010 switch has one slot and the Nexus 5020 switch has two slots for optional expansion modules. The following expansion modules are available:

• N5K-M1404 provides four 10-Gigabit Ethernet ports, and four 1/2/4 Gb Fibre Channel ports.
• N5K-M1600 provides six 10-Gigabit Ethernet ports.
• N5K-M1008 provides eight 1/2/4 Gb Fibre Channel ports.

The expansion modules are field-replaceable units (FRUs) that support online insertion and removal (OIR).

Ethernet Interfaces

The Nexus 5010 switch has 20 fixed 10-Gigabit Ethernet ports equipped with SFP+ interface adapters. The first 8 ports are switchable 1-Gigabit/10-Gigabit ports. Up to 6 additional 10-Gigabit Ethernet ports are available on an expansion module.

The Nexus 5020 switch has 40 fixed 10-Gigabit Ethernet ports equipped with SFP+ interface adapters. The first 16 ports are switchable 1-Gigabit/10-Gigabit ports. Up to 12 additional 10-Gigabit Ethernet ports are available on the expansion modules.

All of the 10-Gigabit Ethernet ports support FCoE. Each port can be used as a downlink (connected to a server) or as an uplink (to the data center LAN).

Fibre Channel Interfaces

Fibre Channel ports are optional on the Cisco Nexus 5000 Series switch. When using expansion modules up to eight Fibre Channel ports are available on the Nexus 5010 switch and up to sixteen Fibre Channel ports are available on the Nexus 5020 switch.

Each Fibre Channel port can be used as a downlink (connected to a server) or as an uplink (to the data center SAN fabric).

Management Interfaces

A Cisco Nexus 5000 Series switch has two dedicated management interfaces (one serial console port and one 10/100/1000 Ethernet interface).

Ethernet Switching

Cisco Nexus 5000 Series switches are designed to support high-density, high-performance Ethernet systems and provide the following Ethernet switching features:

• IEEE 802.1D-2004 Rapid and Multiple Spanning Tree Protocols (802.1w and 802.1s)
• IEEE 802.1Q VLANs and trunks
• IEEE 802.3ad link aggregation
• Private VLANs
• Traffic suppression (unicast, multicast, and broadcast)

FCoE and Fibre Channel Switching

Cisco Nexus 5000 Series switches support data center I/O consolidation (IOC) by providing FCoE interfaces (to the servers) and native Fibre Channel interfaces (to the SAN).

FCoE and Fibre Channel switching includes the following features:

• Cisco fabric services
• N-port virtualization
• VSANs and VSAN trunking
• Zoning
• Distributed device alias service
• SAN port channels

Licensing

Cisco Nexus 5000 Series switches are shipped with the licenses installed. The switch provides commands to manage the licenses and install additional licenses.

QoS

The Cisco Nexus 5000 Series switch provides quality of service (QoS) capabilities such as traffic prioritization and bandwidth allocation on egress interfaces.

The default QoS configuration on the switch provides lossless service for Fibre Channel and FCoE traffic. QoS can be configured to provide additional classes of service for Ethernet traffic.

Serviceability

The Cisco Nexus 5000 Series switch serviceability functions provide data for network planning and help to improve problem resolution time.

This section includes the following topics:

• Switched Port Analyzer
• Ethanalyzer
• Call Home
• Online Diagnostics

Switched Port Analyzer

The switched port analyzer (SPAN) feature allows an administrator to analyze all traffic between ports by nonintrusively directing the SPAN session traffic to a SPAN destination port that has an external analyzer attached to it.

Ethanalyzer

Ethanalyzer is a Cisco NX-OS protocol analyzer tool based on the Wireshark (formerly Ethereal) open source code. Ethanalyzer is a command-line version of Wireshark for capturing and decoding packets. You can use Ethanalyzer to troubleshoot your network and analyze the control-plane traffic. For more information about Ethanalyzer, see Cisco NX-OS Troubleshooting Guide, Release 4.0.

Call Home

The Call Home feature continuously monitors hardware and software components to provide e-mail-based notification of critical system events. A versatile range of message formats is available for optimal compatibility with pager services, standard e-mail, and XML-based automated parsing applications. The feature offers alert grouping capabilities and customizable destination profiles. This feature can be used, for example, to directly page a network support engineer, send an e-mail message to a network operations center (NOC), and employ Cisco AutoNotify services to directly generate a case with the Cisco Technical Assistance Center (TAC). This feature is a step toward autonomous system operation, which enables networking devices to inform IT when a problem occurs and helps to ensure that the problem is resolved quickly.

Online Diagnostics

Cisco generic online diagnostics (GOLD) is a suite of diagnostic facilities to verify that hardware and internal data paths are operating as designed. Boot-time diagnostics, continuous monitoring, and on-demand and scheduled tests are part of the Cisco GOLD feature set. GOLD allows rapid fault isolation and continuous system monitoring.

Switch Management

This section includes the following topics:

• Simple Network Management Protocol
• Role-Based Access Control
• Configuration Methods

Simple Network Management Protocol

Cisco NX-OS is compliant with Simple Network Management Protocol (SNMP) version 1, version 2, and version 3. A full set of Management Information Bases (MIBs) is supported.

Role-Based Access Control

With role-based access control (RBAC), you can limit access to switch operations by assigning roles to users. Administrators can customize access and restrict it to the users who require it.

Configuration Methods

You can configure Cisco Nexus 5000 Series switches using direct network configuration methods or web services hosted on a Fabric Manager server.

This section includes the following topics:

• Configuring with CLI, XML Management Interface, or SNMP
• Configuring with Cisco MDS Fabric Manager

Configuring with CLI, XML Management Interface, or SNMP

You can configure Cisco Nexus 5000 Series switches using the command line interface (CLI), the XML management interface over SSH, or SNMP as follows:

• CLI —You can configure switches using the CLI from an SSH session, a Telnet session. or the console port. SSH provides a secure connection to the device.
• XML Management Interface over SSH—You can configure switches using the XML management interface, which is a programming interface based on the NETCONF protocol that complements the CLI functionality. For more information, see the Cisco NX-OS XML Management Interface User Guide, Release 4.0.
• SNMP—SNMP allows you to configure switches using Management Information Bases (MIBs).

Configuring with Cisco MDS Fabric Manager

You can configure Cisco Nexus 5000 Series switches using the Fabric Manager client, which runs on a local PC and uses the Fabric Manager server.

Network Security Features

Cisco NX-OS Release 4.0 includes the following security features:

• Authentication, authorization, and accounting (AAA) and TACACS+
• RADIUS
• Secure Shell (SSH) Protocol Version 2
• Simple Network Management Protocol Version 3 (SNMPv3)
• MAC ACLs and IP ACLs, including port-based ACLs (PACLs) and VLAN-based ACLs (VACLs).

Virtual Device Contexts

Cisco NX-OS can segment operating system and hardware resources into virtual device contexts (VDC) that emulate virtual devices. The Cisco Nexus 5000 Series switch does not support multiple VDCs. All switch resources are managed in the default VDC.

Ethernet TOR Switch Topology

The Cisco Nexus 5000 Series switch can be deployed as a 10-Gigabit Ethernet top-of-rack (TOR) switch, with uplinks to the data center LAN distribution layer switches. An example configuration in shown in Figure 1-2.

In this example, the blade server rack incorporates blade switches that support 10-Gigabit Ethernet uplinks to the Cisco Nexus 5000 Series switch. The blade switches do not support FCoE, so there is no FCoE traffic and no Fibre Channel ports on the Cisco Nexus 5000 Series switch.

In the example configuration, the Cisco Nexus 5000 Series switch has Ethernet uplinks to two Catalyst switches. If STP is enabled in the data center LAN, the links to one of the switches will be STP active and the links to the other switch will be STP blocked.

Figure 1-2 Ethernet TOR Switch Topology

All of the server-side ports on the Cisco Nexus 5000 Series switch are running standard Ethernet. FCoE is not required, so the server ports are connected using 10-Gigabit Ethernet NICs.

The servers are connected to the data center SAN through MDS 9134 SAN switches. The server Fibre Channel ports require standard Fibre Channel HBAs.

IOC Topology

Figure 1-3 shows a typical I/O consolidation (IOC) scenario for the Cisco Nexus 5000 Series switch.

Figure 1-3 I/O Consolidation Topology

The Cisco Nexus 5000 Series switch connects to the server ports using FCoE. Ports on the server require converged network adapters. For redundancy, each server connects to both switches. Dual-port CNA adapters can be used for this purpose. The CNA is configured in active-passive mode, and the server needs to support server-based failover.

On the Cisco Nexus 5000 Series switch, the Ethernet network-facing ports are connected to two Catalyst 6500 switches. Depending on required uplink traffic volume, there may be multiple ports connected to each Catalyst 6500 switch, configured as port channels. If STP is enabled in the data center LAN, the links to one of the switches will be STP active and the links to the other switch will be STP blocked.

The SAN network-facing ports on the Cisco Nexus 5000 Series switch are connected to Cisco MDS 9000 Family switches. Depending on required traffic volume, there may be multiple Fibre Channel ports connected to each MDS 9000 Family switch, configured as SAN port channels.