Monday, 30 March 2026

Cisco Nexus 5K overview

Product details:
www.cisco.com/go/nexus

5K and 6K have similar features but 6K has up to 96 ports on 40GE

5K's are more common in the wild as they have the same features

http://www.cisco.com/c/en/us/products/switches/nexus-5000-series-switches/models-comparison.html


UP means unified ports. The ports can be Ethernet or FC. So the 5K is Ethernet and fiber channel switch.

7K core
1/10/40/100Gbps Ethernet
L2 and L3 LAN swtiching
Highly redundant. multiple cards and links, power etc

5K Aggregation or access layer switch
LAN and SAN switch
1/10/40 Gbps
L2 and L3 Land swtich
FCoE and native FC SAN switching

4K is specifically for IBM blade servers

3K is used for low latency

2K is an extension of another switch (fabric extension)
2K needs an upstream switch to be the brains
Can't work on its own
Acts like a remote line card of a parent
2K does not have a MAC addresses table it has to ask the parent switch
2K aren't so good for a lot of East West traffic moving across your network
You would want a normal switch for lots of East/West traffic
2K are good in North south, traffic coming in at the internet and heading down to servers
They still have 10GigE up and down so it will work for small environments
Fabric extenders can cut down physical platforms and wiring in the network

Unified Fabric Design

End of Row (EoR) design
You have a rack of network equipment (like catalyst 6500)
Terminate all of the links that go to servers etc
Data Center top of tack architecture design under 5K white papers
[srv] [srv] [srv] [network equipment] (at the end of the row)

40 servers usually more than one cable per server
If you keep adding racks of servers you hit distance limitations
EoR design becomes and issue when you scale up to large amount of servers

Alternative is Middle of Row (MoR)
We install network equipment for each block of servers
[srv] <- [network equipment] [network equipment] -> [srv]

NIC ethernet
HBA for storage

Unified wire, send LAN and SAN traffic down the same cable.
Ethertype 8906 FCOE

Top of Rack (ToR)
Switches in the top of the rack
[network equipment]
[srv]
[srv]

Copper runs from servers to top of rack switch
Top of rack switches connect via fiber back to end of row core
Replaces fiber with copper between servers so that's a big saving

Top of rack with unified fabric

2Ks are Top of rack
[2K]
[2K]
[srv]

2K connect back to 5Ks at EoR
[5K]
[5K]

SFP's lets you change what cables you can plug in.
Make sure the SFPs are supported by your line card.
SFP costs can add up quickly.

Virtual device contexts (VDC)
L1 virtualization
Separation of control and data plane
Separation of the management plane
Separate user DB
Create virtual switches separated just like physical switches.
Takes the physical switch and basically makes more physical switches out of on chasis
To connect two VDCs you need to connect them with physical cabling
Physical ports are members of a single VDC

Virtual SAN 
Much like VLAN
separates fiber channel control and data plane
VLAN and VSAN are L2 virtualization techniques

Virtual routing and forwarding (VRF)
Separates the L3 data and control plane
Lets take 4 interfaces
interfaces 1,2 are in VRF A
interfaces 3,4 are in VRF B
We can run OSPF inside each VRF
Use the "switchto" command to change context

Upgrading nexus

The "install all" command will tell us if it will do a disruptive or not upgrade. 

download images from cisco
make note of checksum from cisco site
fciv -md5 filename.bin
compare hash
copy to USB or SCP or HTTP etc
sh ver | i .bin
install all kickstart kickstart.bin system n70001a.bin

EPLD
Electronic programmable logic devices
These are in the line cards 

download epld from cisco
install all epld bootflash://n7000-epld7.img



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