Interesting Visualization: Configuring Virtual PortChannel (vPC) of Cisco NX-OS

This video from Volvo Trucks is telling exactly how I feel when I configure Virtual PortChannel (vPC).

If I configured the two powerful trucks (NX-OS devices) well, I could make them run powerfully smooth.

However, if I made just one single mistake, I could also go terribly wrong.

Default reserved VLAN numbers on Cisco IOS and NX-OS

Fire-like Kapok blossoms in Taipei City, Taiwan

To show the reserved VLAN numbers on both IOS and NX-OS, the common command is:

show vlan internal usage

Notes of PONG command on Nexus 7000

Mountain view over Devine Trees near Chilan (棲蘭), Yilan County, Taiwan. (棲蘭神木園)

We can use PONG command to measure and and analyze switch port to other switch port latency. Example of using this command can be found on PONG command reference.

Cisco NX-OS vPC (Virtual PortChannel) Configuration Notes

To enable Multi-chassis EtherChannel (MEC) on Cisco Nexus data center switches, the only option left for you is to enable Virtual PortChannel (vPC).

Virtual PortChannel is not that easy for people to configure correctly by hand. Even In this “Quick” vPC Configuration Guide, we still have to do 8 long steps before we have some working vPCs. A little bit frustrating when we look at it for the first time.

Here I just want to point out one aspect to make you feel better about vPC.

Cisco NX-OS MOTD configuration and verification

In NX-OS, the command to configure MOTD (Message of the Day, Wiki) banner is exactly the same as IOS.

http://www.cisco.com/en/US/docs/switches/datacenter/sw/6_x/nx-os/fundamentals/command/reference/fnd_commands.html#wp1571839

Displaying text file contents on Cisco IOS and NX-OS

[Cisco IOS]

For Cisco IOS platforms, we use the command more.
http://www.cisco.com/en/US/docs/ios/fundamentals/command/reference/cf_m1.html#wp1022989

Enable Jumbo Frame function of Cisco Nexus 5000 and 7000

An autumn view of Taipei Campus of National Taipei University (NTPU).

For Data Center networking, and in most of the cases, jumbo frames should be enabled. However, Jumbo frame feature is not enabled by default. So the next question would be "How to enable them in Cisco's Data Center switches such as Nexus 5000 and Nexus 7000 families"?

The answer is in this page on Cisco's official site.

No more CMP on Nexus 7000 next-generation supervisor modules Sup2 and Sup2E

Connectivity Management Processor (CMP) is like an embedded terminal server dedicated for a single Nexus 7000 data center switch. I personally like this feature because we do not have to prepare another set of terminal server just to monitor the console output while we reboot the switch.

However, starting from Supervisor 2 (Sup2) and Supervisor 2 Enhanced Module (Sup2E), CMP hardware is removed from supervisor module itself.

I am not sure whether this feature will come back in the future or not. For the time being, we will have to prepare terminal servers or reserve asynchronous serial ports for Nexus 7000 switches administration.


[Supervisor 1]

Captured on Cisco.com.

1	CMP Status LED	4	ACT LED
2	Link LED	5	CMP MGMT Ethernet LED
3	CMP MGMT Ethernet port

1

CMP Status LED

4

ACT LED

2

Link LED

5

CMP MGMT Ethernet LED

3

CMP MGMT Ethernet port

Strange "rollback" failure of Cisco Nexus 5500

Left to right: "Taipei 101" and "International Trade Building (ITB)"
Taipei City, Taiwan.

After doing "write erase" and reboot, Cisco Nexus 5500 will fail to rollback even to its previously saved configuration files of checkpoints!

Avoiding human errors with Cisco NX-OS "Grace Periods"

Looking out to Guishan Island (the left top far)
Taken around Northeast Coast National Scenic Area (東北角海岸國家風景區), Yilan County, Taiwan.

Cisco offers “Evaluation” time intervals (Grace Periods) for some features of Cisco NX-OS on Data Center switches such as Nexus 7000 or Nexus 5000. It is a nice design because customer can evaluate whether those specific features are suitable for their needs or not, before they really buy that license. This is also very useful for PoC (Proof of Concept) installation.

It is really simple to start evaluation. First we enable evaluation grace periods by “license grace-period” command. Then we only have to type “feature X” commands at the CLI as if we have bought the license.