cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
1825
Views
0
Helpful
3
Replies

Cisco Nexus 7000 netflow - missing data

chunsingkerk
Level 1
Level 1

Hi,

I've configured N7K to export layer 2 flows. Using 2 different flow collectors (open source and commercial), gaps/drops in the reported traffic are observed on a periodic basis.

Problem doesn't seems to be with the exporters, hence I wondering if netflow configuration on N7K can be tweaked to address this symptom.

pmacct.png

scrutinizer.png

Using the 'show exporter' command, no errors/drops are observed.

Here is my configuration:

======

flow record L2-Custom-Flow-Record

  match datalink mac source-address

  match datalink mac destination-address

  match datalink ethertype

  collect counter bytes

  collect counter packets

flow monitor TEST

  record L2-Custom-Flow-Record

  exporter FlOW-COLLECTOR

  exporter PLIXER

interface Ethernetx/y

...

  mac packet-classify

  layer2-switched flow monitor TEST input 

  no shutdown

====

switch: sh flow timeout

Flow timeout values

    Active timeout:           60 seconds

    Inactive timeout:         15 seconds

    Fast timeout:             Disabled

    Session aging timeout:    Disabled

    Aggressive aging timeout: Disabled

=====

I'm using NX-OS 5.0(5)

Anybody know what's wrong?

Kerk Chun Sing

3 Replies 3

ameya_oke
Level 1
Level 1

Hi Kerk,

After exactly 30 minutes the drop occurs, I believe some process triggers on Monitoring tool which is causing this.

Did you try plotting the graph on some other monitoring tool?

It need not be a Nexus issue.

Check for logs on Nexus and on monitoring tool as well.

Are you getting the same kind of trend with graphs for other devices?

Warm Regards

Ameya Oke

Hi Ameya,

Yes, I've exported and graph on 2 different monitoring tools. It is shown in the white (pmacct/cacti) and black (Plixer Scrutinizer) background graphs. The Plixer folks couldn't figure out what could be the problem as well.

Kerk Chun Sing

I only have flexible netflow running on nx-os at L3 but looking at the doc theres a bit more required for L2 flows

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/5_x/nx-os/system_management/configuration/guide/sm_nx_os_cg/sm_15netflow.html

Configuring Layer 2 NetFlow

You can define Layer 2 keys in flexible NetFlow records that you can use to capture flows in Layer 2 interfaces. The Layer 2 keys are as follows:

•Source and destination MAC addresses

•Source VLAN ID

•EtherType from the Ethernet frame

You can apply Layer 2 NetFlow to the following interfaces for the ingress direction:

•Switch ports in access mode

•Switch ports in trunk mode

•Layer 2 port channels.

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: