Netflow will only summarize Layer 3 traffic. This means you will only see traffic that passes from one VLAN to another (interVLAN) or routed traffic. These are layer 2 ports, and its not possible to configure Netflow on them. To see the layer 3 switched traffic, you need to enable Netflow on the VLAN interface.
What OSI layer is Netflow?
It is a stateless packet sampling protocol designed for fast monitoring samplings. sFlow can provide statistics on different protocols from Layer 2 to Layer 7 of the OSI model. Large, 1 – 1000s. Depending on configuration.
What is included in Netflow data?
NetFlow is a rich source of metadata (data about data) that is normally generated by network infrastructure devices, such as routers, firewalls, switches, wireless access points and so on, about the network traffic that is passing through those devices.
What port is NetFlow?
NetFlow Listener port: 9996, UDP, to receive NetFlow exports from routers.
Which device does NetFlow operate on?
NetFlow is a feature that was introduced on Cisco routers around 1996 that provides the ability to collect IP network traffic as it enters or exits an interface.
What is NetFlow protocol?
What is the NetFlow protocol? NetFlow is a protocol developed by Cisco Systems to record all IP traffic flows traversing a router or switch that is NetFlow enabled.
How does NetFlow work on a router?
NetFlow is a network protocol system created by Cisco that collects active IP network traffic as it flows in or out of an interface. The NetFlow data is then analyzed to create a picture of network traffic flow and volume — hence the name: NetFlow.
How NetFlow works on a router?
Can I use NetFlow to get layer 2 traffic visibility?
When working through configurations with customers I am often asked, “Can I use NetFlow to get layer 2 traffic visibility?” On some Cisco switch models, the answer is YES. You can use a layer2-switched option on the monitor, or as shown in the example below, configure a unique layer 2 flow monitor on the layer 2 interfaces.
Why does netnetflow not show switched traffic on the vlan interface?
NetFlow only summarizes traffic that passes from one VLAN to another (interVLAN) or routed traffic which does not show layer 3 switched traffic. This is due to disabled NetFlow on the VLAN interface.
Is flexflexible NetFlow supported on the Layer 2 port-channel interface?
Flexible NetFlow is not supported on the Layer 2 port-channel interface, but is supported on the Layer 2 port-channel member ports. Flexible NetFlow is not supported on the Layer 3 port-channel interface, but is supported on the Layer 3 port-channel member ports.
Can a flow monitor be shared across multiple interfaces?
A flow monitor cannot be shared across Layer 3 physical interfaces and logical interfaces (such as, Layer 3 port-channel interface, Layer 3 port-channel member, and switch virtual interface [SVI]), but a flow monitor can be shared across logical interfaces or Layer 3 physical interfaces.
