Agent to Collector Datagrams

After gathering packet and counter samples, each sFlow agent creates a packet of the data and sends it to an sFlow collector in UDP datagrams. The datagrams contain the IP address of the sFlow collector and the standard UDP destination port number of 6343. Using a standardized port helps avoid configuration between sFlow agents and collectors. If the sFlow agent is configured for counter sampling or packet sampling, or both, an sFlow datagram can contain either interface counters, packet samples, or a mixture of both.

The following table provides information about the contents of sFlow datagrams:

Packet Header



The sFlow version used on the network.

IP Address Type

An IPv4 or IPv6 address

Source IP Address

The IP address of the sFlow agent

Sequence Number

The sequence number of the datagram

System Uptime

The length of time that the system is operational.

Sample Count

The number of samples in the datagram

Ingress Interfaces

The ifindex of the switch port where the packets entered the agent.

Egress Interfaces

The ifindex of the switch port where the packets exited the agent.

Sample dataset

sFlow-specific parameters:

Sequence Numbers

Sampling Rate

Total Packets available for sampling

Number of sampled packets dropped because there was no processing resource for them.

Packet Samples

Packet sample information and may contain several samples.

Packet data

The sampled data that may include the packet payload data and the number on length of protocol headers. This information depends on the size of the size, up to 200 bytes.

Counter Sample

Counter statistical information - fitted in where space permits.

If index

The ifindex of the interface related to the counters.

Physical Interface Parameters


Duplex mode

Admin status

Operational status of the interface

In Counters








Out Counters





Promiscuous Mode

The private VLAN promiscuous mode of the interface

Ethernet Statistics

Alignment Errors

FCS Errors

SQE Errors

Deferred Transmission

Internal MAC errors

Carrier sense errors

Overlength frame errors

Symbol errors