NX-OS Modularity

NX-OS. Nexus Operating System. This operating system has a rich pedigree with its forefathers being heavily embedded in the storage world. SAN-OS originated from the Cisco MDS offerings which has been around since early last decade! Being thrust into the data-centre my exposure to Nexus equipment has sky-rocketed including NX-OS.

Modularity plays a crucial role in NX-OS ability to achieve such fantastic up times. Features themselves can be enabled and disabled as required. This benefit can be seen as a positive in numerous ways. By having features run as separate processes this allows a reduction of memory and CPU process. Don’t need OSPF? Don’t enable. Want vPC but not VTP? Well adjust accordingly. The other great bonus to this is that if OSPF gets AIDS from a neighbour adjacency you don’t lose the box. Simply restart the modular process and major outage avoided.

There are some things to note regarding enabling features and ensuring them to be functional. Turning something on! I know from my IOS experience everything is on by default and it is just the matter of configuring the feature.

N5K-LAB-01(config)# feature ?
 adapter-fex Enable/Disable adapter-fex feature
 bgp Enable/Disable Border Gateway Protocol (BGP)
 dhcp Enable/Disable DHCP Snooping
 eigrp Enable/Disable Enhanced Interior Gateway Routing Protocol (EIGRP)
 fcoe Enable/Disable FCoE/FC feature
 fcoe-npv Enable/Disable FCoE NPV feature
 fex Enable/Disable FEX
 flexlink Enable/Disable Flexlink
 hsrp Enable/Disable Hot Standby Router Protocol (HSRP)
 interface-vlan Enable/Disable interface vlan
 lacp Enable/Disable LACP
 msdp Enable/Disable Multicast Source Discovery Protocol (MSDP)
 ospf Enable/Disable Open Shortest Path First Protocol (OSPF)
 pim Enable/Disable Protocol Independent Multicast (PIM)
 poe Enable/Disable PoE
 private-vlan Enable/Disable private-vlan
 privilege Enable/Disable IOS type privilege level support
 rip Enable/Disable Routing Information Protocol (RIP)
 ssh Enable/Disable ssh
 tacacs+ Enable/Disable tacacs+
 telnet Enable/Disable telnet
 udld Enable/Disable UDLD
 vpc Enable/Disable VPC (Virtual Port Channel)
 vrrp Enable/Disable Virtual Router Redundancy Protocol (VRRP)
 vtp Enable/Disable Vlan Trunking Protocol (VTP)

Look at that. Simple. Just remember to check that a feature is on before configuring it and panicking that you’ve got the wrong licence!

N5K-LAB-01(config)# feature vpc

Feature running! Presto! Now remember you can use show feature to gain a quick overview of what is enabled and what is disabled.

THO-EST-SVRSW-P1-1# sh feat
Feature Name          Instance  State
--------------------  --------  --------
Flexlink              1         disabled
adapter-fex           1         disabled
bgp                   1         disabled
dhcp                  1         disabled
eigrp                 1         disabled
eigrp                 2         disabled
eigrp                 3         disabled
eigrp                 4         disabled
fcoe                  1         disabled
fcoe-npv              1         disabled
fex                   1         enabled
hsrp_engine           1         disabled
interface-vlan        1         enabled
lacp                  1         enabled
ldap                  1         disabled
lldp                  1         enabled
msdp                  1         disabled
ospf                  1         disabled
ospf                  2         disabled
ospf                  3         disabled
ospf                  4         disabled
pim                   1         disabled
poe                   1         disabled
private-vlan          1         disabled
privilege             1         disabled
rip                   1         disabled
rip                   2         disabled
rip                   3         disabled
rip                   4         disabled
sshServer             1         enabled
tacacs                1         enabled
telnetServer          1         enabled
udld                  1         enabled
vem                   1         disabled
vpc                   1         enabled
vrrp                  1         disabled
vtp                   1         enabled

I really have taken to the concept of this modularity. I hope it works as long as it isn’t licensed to stupidity like the ASA has become. My only gripe thus far – Y U NO SAFE HARBOUR?!

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