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:
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Packet-based sampling: An sFlow enabled port samples
one packet out of a configurable number of packets passing through it.
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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:
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Supporting traffic monitoring on Gigabit and
higher-speed networks.
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Providing scalability to allow one sFlow
collector to monitor multiple or more sFlow agents.
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Implementing the low-cost sFlow agent.
Figure
1-1 Network diagram for sFlow configuration
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Host A and Server are connected to Switch
through GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 respectively.
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Host B works as an sFlow collector with IP
address 3.3.3.2 and port number 6343, and is connected to Switch through
GigabitEthernet 1/0/3.
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GigabitEthernet 1/0/3 belongs to VLAN 1, having
an IP address of 3.3.3.1.
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Run sFlow agent on Switch, and enable sFlow on
GigabitEthernet 1/0/1 to monitor traffic on this interface. Switch sends sFlow
packets through GigabitEthernet 1/0/3 to Host B, which then analyzes the sFlow
packets and displays the results.
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Product series
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Software version
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Hardware version
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S5500-EI Series Ethernet Switches
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Release 2102
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All versions
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# Configure
an IP address for the sFlow agent.
<Switch>
system-view
[Switch]
sflow agent ip 3.3.3.1
# Specify
the IP address and port number of the sFlow collector. The default port number
of the sFlow collector is 6343.
[Switch]
sflow collector ip 3.3.3.2
# Set the sFlow interval to 30 seconds.
[Switch]
sflow interval 30
# Enable sFlow in the inbound direction on
GigabitEthernet 1/0/1.
[Switch]
interface GigabitEthernet 1/0/1
[Switch-GigabitEthernet1/0/1]
sflow enable inbound
# Specify the traffic sampling rate as 100000,
that is, configure the port to sample one out of 100000 packets passing through
it.
[Switch-GigabitEthernet1/0/1]
sflow sampling-rate 100000
# Display the sFlow configuration
information.
[Switch-GigabitEthernet1/0/1]
display sflow
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
GE1/0/1 Inbound
100000 Random Active
#
sflow
agent ip 3.3.3.1
sflow
collector ip 3.3.3.2
sflow
interval 30
#
interface
GigabitEthernet1/0/1
sflow
enable inbound
sflow
sampling-rate 100000
#
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S5500-EI series Ethernet switches do not support
the sflow sampling-mode determine command. That is, the sFlow sampling
mode cannot be specified as determine.
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Currently, only the sFlow agent function is
supported on S5500-EI series Ethernet switches, and only one IP address can be
specified for the sFlow agent.
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Currently, you can specify two sFlow collectors
(one for backup) with different IP addresses for an S5500-EI series Ethernet switch.
The switch will send sFlow packets to the two sFlow collectors at the same
time.
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The sFlow agent and sFlow collector must not
have the same IP address.
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You can specify the IP address of the loopback
interface on the device as the sFlow agent’s interface.
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If you want to enable sFlow on an aggregation
group, you need to enable sFlow on each member port.
