how to set up fabric extender

[robertkwild]

hi all,

we have nexus 7000's with FEX switches but im planning to buy more FEX's on ebay, in particular this one

N2K-C2248TP-1GE

just wondering how you set them up as someone said all you do is create a PO for it and thats it?

thanks,

rob

[Mark Elsen]

 - FYI  : https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus2000/sw/configuration/guide/rel_521/Configuring_the_Cisco_Nexus_2000_Series_Fabric_Extender_rel_5_2_chapter2.html#task_90B3DE7857AE4B008933DB885323D140

     Yet , I myself would never buy such datacenter critical  equipment on ebay , only from  Cisco reseller ,

 M,

[robertkwild]

thanks @Mark Elsen im missing a couple of rack ears for the FEX's, what ones from below are good for the FEX's

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=cisco+rack+mount+ears&_sacat=0&_odkw=cisco+rack+mount+ears&_osacat=0

[balaji.bandi · Accepted solution]

Is the nexus in vPC 

check the matrix :

https://www.cisco.com/c/dam/en/us/td/docs/switches/datacenter/nexus7000/sw/matrix/technical/reference/Module_Comparison_Matrix.pdf

you looking FEX to to dual homed or single homed ?

Single home simple config on nexus 7K

Nexus7K01# configure terminal
Nexus7K01(config)# interface port-channel 100
Nexus7K01(config-if)# switchport mode fex-fabric
Nexus7K01(config-if)# fex associate 100
Nexus7K01(config-if)# exit
Nexus7K01(config)# interface ethernet 1/28
Nexus7K01(config-if)# switchport mode fex-fabric
Nexus7K01(config-if)# fex associate 100
Nexus7K01(config-if)# channel-group 100
Nexus7K01(config-if)# exit
Nexus7K01(config)# interface ethernet 1/29
Nexus7K01(config-if)# switchport mode fex-fabric
Nexus7K01(config-if)# fex associate 100
Nexus7K01(config-if)# channel-group 100
Nexus7K01(config-if)# exit

if you have dual home

apply the same config on other nexus

and apply below config on both the switches and connect the cables and check.

Nexus7K01(config)# interface port-channel 100

Nexus7K01(config)# vpc 100

[robertkwild]

yeah the switches in vPC but tbh im just going to plug the FEX's in one switch as plugging in both will require more sfp modules, more fiber cables and take up more valuable 10gig ports on the nexus 7000 blades

but if i did do dual home would i need to mirror the same ports so if i were to plug it in

SW1 eth1/1,eth2/1

would i need to plug it in the same ports on SW2 or can one be plugged in 2/2 instead of 2/1

also i have read if you dual home your FEX's you can only use half the number of FEX switches

[robertkwild]

instead of doing this

switch# configure terminal
switch(config)# interface port-channel 4
switch(config-if)# switchport mode fex-fabric
switch(config-if)# fex associate 101
switch(config-if)# exit
switch(config)# interface ethernet 1/28
switch(config-if)# switchport mode fex-fabric
switch(config-if)# fex associate 101
switch(config-if)# channel-group 4
switch(config-if)# exit
switch(config)# interface ethernet 1/29
switch(config-if)# switchport mode fex-fabric
switch(config-if)# fex associate 101
switch(config-if)# channel-group 4
switch(config-if)# exit
switch(config)# interface ethernet 1/30
switch(config-if)# switchport mode fex-fabric
switch(config-if)# fex associate 101
switch(config-if)# channel-group 4
switch(config-if)# exit
switch(config)# interface ethernet 1/31
switch(config-if)# switchport mode fex-fabric
switch(config-if)# fex associate 101
switch(config-if)# channel-group 4

cant you just do

switch# configure terminal
switch(config)# interface port-channel 101
switch(config-if)# switchport mode fex-fabric
switch(config-if)# fex associate 101
switch(config-if)# exit
switch(config)# interface ethernet 1/28-31
switch(config-if)# switchport mode fex-fabric
switch(config-if)# fex associate 101
switch(config-if)# channel-group 101
switch(config-if)# exit

[robertkwild]

worked a treat, all i did was this

switch(config)# interface ethernet 1/28-31
switch(config-if)# switchport mode fex-fabric
switch(config-if)# fex associate 120
switch(config-if)# channel-group 120

switch(config-if)#no shut

switch(config-if)# exit

[balaji.bandi]

Sure that also works - it all depends on the requirement. single home vs dual home - both the option available - we need to choose which is the right choice.