Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 2093)

sFlow Introduction and Configuration
Software Reference for x310 Series Switches
C613-50046-01 REV A AlliedWare Plus TM Operating System - Version 5.4.4C 80.13
sFlow Datagrams
After data sampling and counter information has been gathered, each sFlow agent
packetizes the data and sends it to an sFlow collector where it can be analyzed and
displayed in charts and tables etc.
This packetized data is sent to the collector in UDP datagrams. These datagrams bear the
IP address of the collector and the port number 6343. Using a standardized port helps to
avoid configuration problems between the sFlow agents and collectors.
Although an analysis of the sFlow datagrams is outside the scope of this document, some
basic information is provided here for those interested in knowing the basic components
of the sFlow datagrams. The full specification of the sFlow protocol can be found at
www.sflow.org/sflow_version_5.txt .
sFlow datagrams comprise three basic components:
■ Datagram header information
■ Flow sample information - may contain several samples
■
Counter statistical information - fitted in where space permits
Figure 80-4: sFlow Datagram Encapsulation
The content of these datagram components is listed below:
sFlow Header
Fields
■
Version (The sFlow version being used)
■
IP Address Type (Can be either an IPv4 or IPv6 address type)
■ Source IP Address (The IP address of the sFlow agent)
■
Sequence Number (The datagram sequence number)
■
System Up-time
■
Sample Count (The number of samples in the datagram)
■ Sample Dataset
sFlow Flow Sample
Fields
■
Flow Sample 1 (The first sample)
■
Sample Type (Flow Sample, 0x0001)
■
Sample Sequence Number (of flow samples)
■ Sampler ID
■
Sampling Rate (as set by the “sflow sampling-rate” on page 81.13 or SNMP)
■
Sample Pool (the total number of packets that could have been sampled)
■
Packets Dropped (the number of packets dropped, due to a lack of resources)
■ Input (the interface that the packet was received on - not supported)
■ Output (the index number of the interface that the packet was sent from)
(Note that your collector should have the ability via SNMP to resolve index numbers to
physical port numbers)
■
Packet Type
■ Header Protocol - Ethernet ISO 88023(1)
■
Packet Size (Frame Length including the FCS)
■
Header Length - The sampled portion of the frame as set by the “sflow max-header-
size” on page 81.10 . May be shorter for small frames.
■
Header Bytes
sFlow-datagram
sFlow Datagram Encapsulation
UDP Header sFlow Header Sampled Data Counter Data Sampled Data Sampled Data