Chapter 1 Interfaces Overview; Trunks And Portchannels - Cisco MDS 9000 Series Configuration Manual

S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Interfaces Overview
This chapter describes the basic interfaces that are used with Fabric Manager. These interfaces include
Gigabit Ethernet interfaces, Fiber Channel interfaces, virtual interfaces on Nexus hardware, buffer
credits, management interfaces, VSAN interfaces, shared interface resources, trunking, PortChanneling,
N port virtualization (NPV), and FlexAttach virtual pWWN.
This chapter includes the following topics:
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Trunks and PortChannels

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.
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.
OL-19445-02, Cisco MDS NX-OS Release 4.2(x)
Trunks and PortChannels, page 1-1
Fibre Channel Port Rate Limiting, page 1-2
Extended Credits, page 1-2
N Port Virtualization, page 1-2
FlexAttach, page 1-2
C H A P T E R
Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
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