Cisco NexusUnified Fabric

The Nexus Hardware

Nexus 7000

• Three power supplies, five fabric modules, two fabric fan trays, and two system fan trays and dual supervisors.

Nexus 5000

• Dual power supplies and the power connectors on the same side as the data ports. The hot-swappable portion of the power supply is found (and removed) from the opposite end of the switch.

• As of version 5.0 of NX-OS, the 5000s don’t support SVIs or routing, and support only 512 VLANs.

Nexus 2000

• The Nexus 2000 devices are not switches, but rather fabric extenders. FEXs can be thought of as external blades for Nexus switches.

• Don’t have console ports. To use a FEX, you must connect it to a higher-tier Nexus switch like a 5000 or 7000.

Unified fabric provides the ability to combine traditional networking with storage networking in a single connector.

NX-OS versus IOSIf we type a show command in the config mode, NX-OS is smart enough to know and shows the answer we are really looking forNo more speed-related interface names

No hidden configuration in NX-OS

Interface status displays operational state along with a reason

No more write memory

No more do command

No more show arp

No more interface range command

Slash notation supported on all IPv4 and IPv6 commands

Two CLI help levels

Routing configuration mostly within interfaces

Many more pipe options

Nexus Design FeaturesManagement and control plane is separate from data plane

Out-of-band management supported

Lights-out management on 7000 series

High-speed backplane on 7000 series

N+1 redundancy on 7000 series

Hardware forwarding engines on every I/O module (7000 series)

Scalability

Virtualization

Resiliency

Integration of L3 routing, L2 switching, and SAN switching

Support for multiprocessor and multithreaded CPUs

Virtual Device Contexts

The Nexus 7000s are capable of being

split into multiple logical switches

Only the 7000 series of Nexus switches

supports VDCs, only support up to four

VDCs

Once created, the VDC appears as if it is a newly initialized

Nexus switch

The show CDP neighbors command executed from

within the VDC shows that it sees other contexts as

devices, but only when we have a physical Ethernet cables connecting them.

Dedicated Rate-Mode on a PortConfig

ure the

switch to

allow the

maximum

throughput on a

port at the

expense of other ports.

Each

ASIC

controls a

group of port

s

Allows us to

dedicate all

the ASIC’s resources to one port on

these modul

es

It disables all of the othe

r ports controlled by

that ASIC

May be

used for

devices

that pull in a lot of

traffic from multiple

sources

Fabric Extenders (FEXs) -Nexus 2000 topologies

Cross over Mode Pass Thru Mode

Pinning the port channel

Allows us to assign banks of ports to individual

uplinks instead of having all the ports share a single EtherChannel.

Increase in usable uplink

One of the uplinks failure causes all of the

pinned ports to go down.

There is no dynamic healing

Virtual Port Channel vPCUsed in a cross-connect design, binding the links to Higher-Tier Nexus switches together

Two switches will have one data plane and two control planes

vPCs require a link between the vPC peer switches called a peer keep alive link

vPC requires that a link—preferably a trunk—between the vPC peers be defined as a peer link. This link will be used for the traversal of traffic necessary to utilize the vPC.

vPCs rely on the configuration of each side of the link to match exactly

• Type -1 parameters must match, or the vPC will not form (or will break if already formed).• Type -2 parameters should match, but the vPCs should not break if they don’t.

• Changing type-2 parameters may cause vPCs to bounce or VLANs to be suspended.

NX-OS Upgrades and configuration

Config-Sync O n c e y o u ’v e c o n fi g u re d a n in te rfa c e o r F E X u s in g th e fe a tu re , y o u m a y n o lo n g e r c o n fi g u re it in c o n fi g -t m o d e .

Configuration RollbackNexus allows creation of restore points and rolling back to those

NX-OS UpgradeA disruptive upgrade means that the entire switch will reboot, ceasing all network traffic traversing the switch.

A non-disruptive, or hitless, upgrade will reload the kernel, but packets will continue to flow during the process.