Netflow on 4948E question

[ALIAOF_]

So 4948E supports netflow lite.  I have heard that it is not very accurate, see link below:  How true is that?  Any one has any experience?

http://blog.sflow.com/2011/05/netflow-lite.html

Secondly here is Cisco documentation to configure netflow lite on 4948e:

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/15.02SG/configuration/guide/nswich_l.html

My questions are:

1- Source and Destination addresses 99.99.99.x where did they come from?

2- I don't have a physical interface configured I have VLAN intefaces (SVI's) can I still use netflow lite?

[jakewilson]

We have support for NetFlow-Lite. To set this up, configure the 4948e to send the NetFlow-Lite to an nProbe.  The nProbe will turn the sampled packets into flows and export them off in IPFIX datagrams to your collector.  I never saw an IP address of 99.99.99.x during our tests and usually NetFlow has to be configured on physical interfaces. 

Regarding sFlow Vs. NetFlow-Lite, I would consider the source of that URL.

[ALIAOF_]

Thank you for the reply very good information about the addresses here is what I meant?

source 9.9.9.10  !IP address where NetFlow-lite data is sourced (What would be the source IP?)

  destination 9.9.9.1  !IP address of the nProbe aggregator (So this would be the IP address of the Server that is gathering data)

Do I need to setup an IP on the physical interface?  There are two 4948 switches connected to each other via port channel in GLBP configuration.  I'm trying to figure out which interface I pick ?