Category Archives: CCNP Data Center

Cisco CCNP Data Center SPAN

There is one topic you need to know for sure and that is SPAN. But SPAN where? Well, everywhere! I would know the SPAN config (and options) for the following:

  • IOS
  • NX-OS

OK, OK, maybe the IOS is a bit of a stretch, but I wanted to include it here for my readers.

A Peek Into SkyNet!

Remember, the Switched Port Analyzer feature is necessary because when we are wanting to do packet captures in the switched infrastructure, the switches will do their jobs and keep us from seeing frames that do not need to be sent to our switch port (with the analyzer). This is the filtering that switches do so well (unlike those stupid hubs).

Notice that while there is variation in the syntax – there is an overall consistency in the approach. It is all about setting the source port(s) correctly and the destination port. As you will see in the NX-OS and UCS examples, the destination port often holds the “bells and whistles” of the configuration.

NOTE: I think it will help if I present the source and destination configurations separated as you will see. This should allow us to really focus on each.

First, an IOS example:


Switch(config)# monitor session 1 source interface gigabitethernet0/1


Switch(config)# monitor session 1 destination interface gigabitethernet0/2 encapsulation replicate

Here is the NX-OS example:


switch(config)# monitor session 3
switch(config-monitor)# source interface ethernet 2/1-3, ethernet 3/1 rx
switch(config-monitor)# source interface port-channel 2
switch(config-monitor)# source interface sup-eth 0 both
switch(config-monitor)# source vlan 3, 6-8 tx
switch(config-monitor)# source interface ethernet 101/1/1-3
switch(config-monitor)# filter vlan 3-5, 7
switch(config-monitor)# exit

NOTE: The keywords for direction are tx, rx, and both


switch(config-monitor)# destination interface ethernet 2/5
switch(config-monitor)# no shut
switch(config-monitor)# mtu 500
switch(config-monitor)# rate-limit 10
switch(config-monitor)# multicast best-effort
switch(config-monitor)# exit

Here is the UCS CLI example:


UCS-A# scope eth-traffic-mon
UCS-A /eth-traffic-mon # scope fabric a
UCS-A /eth-traffic-mon/fabric # create eth-mon-session EthMonitor33


UCS-A /eth-traffic-mon/fabric/eth-mon-session*# create dest-interface 2 12
UCS-A /eth-traffic-mon/fabric/eth-mon-session/dest-interface*# set speed 20gbps
UCS-A /eth-traffic-mon/fabric/eth-mon-session/dest-interface*# commit-buffer

Thanks so much for reading! Oh – and you might want some more info on the UCS config, which is certainly the most interesting. Here is the relevant Cert Guide:

Cisco Data Center – Troubleshooting OTV

Are you ready to enjoy a glimpse into the world of Overlay Transport Virtualization (OTV) troubleshooting. Enjoy this slice of one of our highly rated Cisco Data Center courses at CBTNuggets!


MicroNugget: Troubleshooting LACP in the DC

In this MicroNugget I discuss key troubleshooting points for using LACP when forming Port Channels. This tutorial relates to my Cisco CCNP Data Center 642-980 DCUFT training course. Try CBT Nuggets free for 7 days.