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Table of Contents
Displaying and Maintaining sFlow
Troubleshooting sFlow Configuration
The Remote sFlow Collector Cannot Receive sFlow Packets
Layer 3 Ethernet interfaces mentioned in this section refer to Ethernet ports configured to operate in route mode. For how to switch the operating mode of an Ethernet port, refer to Ethernet Port Configuration in the Access Volume
When configuring sFlow, go to these sections for information you are interested in:
l Displaying and Maintaining sFlow
l Troubleshooting sFlow Configuration
sFlow Overview
Introduction to sFlow
Sampled Flow (sFlow) is a traffic monitoring technology mainly used to collect and analyze traffic statistics.
The sFlow system involves an sFlow agent embedded in a device and a remote sFlow collector. The sFlow agent collects traffic statistics and packets from the sFlow enabled ports on the device, encapsulates the information into sFlow packets, and sends the packets to the sFlow collector. The sFlow collector analyzes the sFlow packets and displays the results.
sFlow has the following two sampling mechanisms:
l Packet-based sampling: An sFlow enabled port samples one packet out of a configurable number of packets passing through it.
l Time-based sampling: The sFlow agent samples the statistics of all sFlow enabled ports at a configurable interval.
As a traffic monitoring technology, sFlow has the following advantages:
l Supporting traffic monitoring on Gigabit and higher-speed networks.
l Providing scalability to allow one sFlow collector to monitor multiple or more sFlow agents.
l Implementing the low-cost sFlow agent.
Currently, only the sFlow agent function is supported on the device.
Operation of sFlow
sFlow operates as follows:
1) With sFlow enabled, a physical port encapsulates sampled data into packets and sends them to the sFlow agent.
2) The sFlow agent periodically collects the statistics of all sFlow enabled ports.
3) When the sFlow packet buffer overflows or the one-second timer expires, the sFlow agent sends sFlow packets to the specified sFlow collector.
Configuring sFlow
The sFlow feature enables the remote sFlow collector to monitor the network and analyze sFlow packet statistics.
Follow these steps to configure sFlow:
|
Use the command… |
Remarks |
|
|
Enter system view |
system-view |
— |
|
Specify the IP address of the sFlow agent |
sflow agent ip ip-address |
Required Not configured by default. |
|
Specify the IP address and port number of the sFlow collector |
sflow collector ip ip-address [ port port-num ] |
Required Not specified by default. |
|
Set the counter sampling interval at which the sFlow agent collects the statistics of sFlow enabled ports |
sflow interval interval-time |
Optional 20 seconds by default. |
|
Specify the sFlow version |
sflow version { 4 | 5 } |
Optional Version 5 by default. |
|
Enter Layer 2 Ethernet port or Layer 3 Ethernet interface view |
interface interface-type interface-number |
— |
|
Enable sFlow in the inbound or outbound direction |
sflow enable { inbound | outbound } |
Required Not enabled by default. |
|
Specify the sFlow sampling mode |
sflow sampling-mode { determine | random } |
Optional By default, the sFlow sampling mode is determine. Currently, only the determine mode is supported on the device. |
|
Specify the number of packets out of which the interface will sample a packet |
sflow sampling-rate rate |
Optional 2000 packets by default. |
l The sFlow agent and sFlow collector must not have the same IP address.
l Currently, you can specify at most two sFlow collectors on the device.
Displaying and Maintaining sFlow
|
To do… |
Use the command… |
Remarks |
|
Display sFlow configuration information |
display sflow |
Available in any view |
sFlow Configuration Example
Network requirements
l Host A is connected with Server through Device (sFlow agent).
l Enable sFlow on Ethernet 1/0/1 to monitor traffic on the port.
l Device sends sFlow packets through Ethernet 1/0/3 to the sFlow collector (Host B), which analyzes the sFlow packets and displays results.
Figure 1-1 Network diagram for sFlow configuration
Configuration procedure
# Specify the IP address of the sFlow agent.
[Device] sflow agent ip 3.3.3.1
# Specify the IP address and port number of the sFlow collector.
[Device] sflow collector ip 3.3.3.2 port 6343
# Set the sFlow interval to 30 seconds.
[Device] sflow interval 30
# Enable sFlow in both the inbound and outbound directions on Ethernet 1/0/1.
[Device] interface ethernet 1/0/1
[Device-Ethernet1/0/1] sflow enable inbound
[Device-Ethernet1/0/1] sflow enable outbound
# Specify the packet sampling rate on the interface.
[Device-Ethernet1/0/1] sflow sampling-rate 10000
# Specify the traffic sampling mode.
[Device-Ethernet1/0/1] sflow sampling-mode random
# Display the sFlow configuration information.
[Device-Ethernet1/0/1] display sflow
sFlow Version: 5
sFlow Global Information:
Agent IP:3.3.3.1
Collector IP:3.3.3.2 Port:6343
Interval(s): 30
sFlow Port Information:
Interface Direction Rate Mode Status
Eth1/0/1 In/Out 10000 Random Active
Troubleshooting sFlow Configuration
The Remote sFlow Collector Cannot Receive sFlow Packets
Symptom
The remote sFlow collector cannot receive sFlow packets.
Analysis
l sFlow is not enabled globally because the sFlow agent or/and the sFlow collector is/are not specified.
l No port is enabled with sFlow to sample data.
l The IP address of the sFlow collector specified on the sFlow agent is different from that of the remote sFlow collector.
l No IP address is configured for the Layer 3 interface on the device, or the IP address is configured, but the UDP packets with the IP address being the source cannot reach the sFlow collector.
l The physical link between the device and the sFlow collector fails.
Solution
1) Check whether sFlow is correctly configured by displaying sFlow configuration with the display sflow command.
2) Check whether the correct IP address is configured for the device to communicate with the sFlow collector.
3) Check whether the physical link between the device and the sFlow collector is normal.
