Cisco Nexus 5000 Series Nx-Os San Switching Configuration Guide - Cisco Nexus 5000 Series Configuration Manual

Overview
SAN Switching Overview
to the core switch. This feature is available only for Cisco MDS Blade Switch Series, the Cisco MDS 9124
Multilayer Fabric Switch, and the Cisco MDS 9134 Multilayer Fabric Switch.
VSAN Trunking
Trunking, also known as VSAN trunking, is a feature specific to switches in the Cisco MDS 9000 Family.
Trunking enables interconnect ports to transmit and receive frames in more than one VSAN, over the same
physical link. Trunking is supported on E ports and F ports.
SAN Port Channels
PortChannels aggregate multiple physical ISLs into one logical link with higher bandwidth and port resiliency
for both Fibre Channel and FICON traffic. With this feature, up to 16 expansion ports (E-ports) or trunking
E-ports (TE-ports) can be bundled into a PortChannel. ISL ports can reside on any switching module, and
they do not need a designated master port. If a port or a switching module fails, the PortChannel continues to
function properly without requiring fabric reconfiguration.
Cisco NX-OS software uses a protocol to exchange PortChannel configuration information between adjacent
switches to simplify PortChannel management, including misconfiguration detection and autocreation of
PortChannels among compatible ISLs. In the autoconfigure mode, ISLs with compatible parameters
automatically form channel groups; no manual intervention is required.
PortChannels load balance Fibre Channel traffic using a hash of source FC-ID and destination FC-ID, and
optionally the exchange ID. Load balancing using PortChannels is performed over both Fibre Channel and
FCIP links. Cisco NX-OS software also can be configured to load balance across multiple same-cost FSPF
routes.
Virtual SANs
Virtual SAN (VSAN) technology partitions a single physical SAN into multiple VSANs. VSAN capabilities
allow Cisco NX-OS software to logically divide a large physical fabric into separate, isolated environments
to improve Fibre Channel SAN scalability, availability, manageability, and network security. For FICON,
VSANs facilitate hardware-based separation of FICON and open systems.
Each VSAN is a logically and functionally separate SAN with its own set of Fibre Channel fabric services.
This partitioning of fabric services greatly reduces network instability by containing fabric reconfigurations
and error conditions within an individual VSAN. The strict traffic segregation provided by VSANs helps
ensure that the control and data traffic of a specified VSAN are confined within the VSAN's own domain,
increasing SAN security. VSANs help reduce costs by facilitating consolidation of isolated SAN islands into
a common infrastructure without compromising availability.
Users can create administrator roles that are limited in scope to certain VSANs. For example, a network
administrator role can be set up to allow configuration of all platform-specific capabilities, while other roles
can be set up to allow configuration and management only within specific VSANs. This approach improves
the manageability of large SANs and reduces disruptions due to human error by isolating the effect of a user
action to a specific VSAN whose membership can be assigned based on switch ports or the worldwide name
(WWN) of attached devices.
VSANs are supported across FCIP links between SANs, which extends VSANs to include devices at a remote
location. The Cisco MDS 9000 Family switches also implement trunking for VSANs. Trunking allows
Inter-Switch Links (ISLs) to carry traffic for multiple VSANs on the same physical link.
Zoning
Zoning provides access control for devices within a SAN. Cisco NX-OS software supports the following types
of zoning:
• N port zoning-Defines zone members based on the end-device (host and storage) port.
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Cisco Nexus 5000 Series NX-OS SAN Switching Configuration Guide

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