Deploying a Nexus 2148t on a Nexus 5020

First, let it be perfectly clear that I know very little about configuring network gear. My CLI experience has been pretty much limited to creating a VLAN. That said, I had to take on the task of deploying a Cisco Nexus 2148t in order to get some new ESXi hosts out on the appropriate network. Fortunately, Scott Lowe wrote an blog post titled Connecting a Nexus 2148 to a Nexus 5010 in which deemed the process “incredibly simple and not really worthy of a blog post.”  Fortunately, the blog post was succinct and accurate, exactly what I needed so hereby deem it priceless.

Being a complete newbie to networking, but also valuing the product of my labors, I decided I needed to port-channel two 10 GB links to each of the Nexus 2148t for link redundancy.  This decision was supported by a blog post titled Why EtherChannels should be used for FEX interfaces.  The essence of the procedure is pretty simple:

  1. Create the port-channel
  2. Set switchport mode of the port-channel to ‘fex-fabric’
  3. Select switchports, set mode ‘fex-fabric, add to port-channel

Mine looks a little like this:

nexus01(config)# int port-channel21
nexus02(config-if)# switchport mode fex-fabric
                                   ^
 % Incomplete command at '^' marker.
nexus02(config-if)#

Of course, that's not really what I was hoping would happen.  A little google'ing, some head scratching and another blog post titled Some NX-OS features can’t be manually enabled gave me a bit of a clue.  I tried:

nexus01(config-if)# show run | i feature
feature telnet
feature udld
feature interface-vlan
feature lacp
feature vpc
  rule 5 permit show feature environment
  rule 4 permit show feature hardware
  rule 3 permit show feature module
  rule 2 permit show feature snmp
  rule 1 permit show feature system

I see nothing about fex, someone enlightened me to the following command.

nexus01(config-if)# show feature
Feature Name          Instance  State
--------------------  --------  --------
tacacs                1         disabled
lacp                  1         enabled
interface-vlan        1         enabled
private-vlan          1         disabled
udld                  1         enabled
vpc                   1         enabled
fcoe                  1         disabled
fex                   1         disabled

More help from the person at CCIEZone.com.

nexus01(config-if)# feature fex
nexus01(config)# show run | i feature
feature telnet
feature udld
feature interface-vlan
feature lacp
feature vpc
feature fex
  rule 5 permit show feature environment
  rule 4 permit show feature hardware
  rule 3 permit show feature module
  rule 2 permit show feature snmp
  rule 1 permit show feature system
nexus01(config)# show feature
Feature Name          Instance  State
--------------------  --------  --------
tacacs                1         disabled
lacp                  1         enabled
interface-vlan        1         enabled
private-vlan          1         disabled
udld                  1         enabled
vpc                   1         enabled
fcoe                  1         disabled
fex                   1         enabled

That looks better.  Now, Scott's steps get me the rest of the way through.

nexus01(config)# interface port-channel 21
nexus01(config-if)# switchport mode fex-fabric
nexus01(config-if)# interface eth1/3
nenexus01xus(config-if)# switchport mode fex-fabric
nexus01(config-if)# channel-group 21 mode on
nexus01(config-if)# interface eth1/4
nexus01(config-if)# switchport mode fex-fabric
nexus01(config-if)# channel-group 21 mode on
nexus01(config-if)# interface port-channel 21
nexus01(config-if)# fex associate 100

To confirm:

nexus01(config-if)# show int port-channel21
port-channel21 is up
  Hardware: Port-Channel, address: 0005.9b24.994a (bia 0005.9b24.994a)
  MTU 1500 bytes, BW 20000000 Kbit, DLY 10 usec,
    reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA
  Port mode is fex-fabric
  full-duplex, 10 Gb/s
  Beacon is turned off
  Input flow-control is off, output flow-control is off
  Switchport monitor is off
  Members in this channel: Eth1/3, Eth1/4
  Last clearing of "show interface" counters never
  1 minute input rate 5680 bits/sec, 0 packets/sec
  1 minute output rate 4629528 bits/sec, 951 packets/sec
  Rx
    221027 input packets 35441 unicast packets 111604 multicast packets
    73982 broadcast packets 35 jumbo packets 0 storm suppression packets
    120356896 bytes
  Tx
    55103126 output packets 1854476 multicast packets
    1245154 broadcast packets 20480285 jumbo packets
    41342764374 bytes
    0 input error 0 short frame 0 watchdog
    0 no buffer 0 runt 0 CRC 0 ecc
    0 overrun  0 underrun 0 ignored 0 bad etype drop
    0 bad proto drop 0 if down drop 0 input with dribble
    0 input discard
    0 output error 0 collision 0 deferred
    0 late collision 0 lost carrier 0 no carrier
    0 babble
    0 Rx pause 0 Tx pause
  2 interface resets

nexus01(config-if)#  show fex detail
FEX: 100 Description: FEX0100   state: Online
  FEX version: 4.1(3)N2(1a) [Switch version: 4.1(3)N2(1a)]
  FEX Interim version: 4.1(3)N2(1a)
  Switch Interim version: 4.1(3)N2(1a)
  Extender Model: N2K-C2148T-1GE,  Extender Serial: JAF1418BKEE
  Part No: 73-12009-06
  Card Id: 70, Mac Addr: 54:75:d0:3a:d7:02, Num Macs: 64
  Module Sw Gen: 12594  [Switch Sw Gen: 21]
 pinning-mode: static    Max-links: 1
  Fabric port for control traffic: Eth1/3
  Fabric interface state:
    Po21 - Interface Up. State: Active
    Eth1/3 - Interface Up. State: Active
    Eth1/4 - Interface Up. State: Active
  Fex Port        State  Fabric Port  Primary Fabric
       Eth100/1/1  Down        Po21        Po21
       Eth100/1/2  Down        Po21        Po21
       Eth100/1/3  Down        Po21        Po21
       ...

Done, save and go home.

Here is some Cisco documentation covering all of this. http://www.cisco.com/en/US/docs/switches/datacenter/nexus2000/sw/configuration/guide/rel_4_0_1a/FEX-Config.html

Leave a Reply

Your email address will not be published. Required fields are marked *