DELL N3000 Manual Do Utilizador

Monitoring Switch Traffic

The primary objective of Counter Sampling is to efficiently, periodically 

export counters associated with Data Sources. A maximum Sampling Interval 

is assigned to each sFlow instance associated with a Data Source.
Counter Sampling is accomplished as follows:

• sFlow Agents keep a list of counter sources being sampled.
• When a Packet Flow Sample is generated the sFlow Agent examines the 

list and adds counters to the sample datagram, least recently sampled first. 

Counters are only added to the datagram if the sources are within a short 

period, 5 seconds say, of failing to meet the required Sampling Interval. 

• Periodically, say every second, the sFlow Agent examines the list of counter 

sources and sends any counters that must be sent to meet the sampling 

interval requirement.

The set of counters is a fixed set.

Like sFlow, RMON is a technology that enables the collection and analysis of 

a variety of data about network traffic. Dell Networking N2000, N3000, and 

N4000 series switches software includes an RMON probe (also known as an 

RMON agent) that collect information and analyze packets. The data that is 

collected is defined in the RMON MIB, RFC 2819.
RMON is defined in an Internet Engineering Task Force (IETF) specification 

and is an extension of the SNMP MIB. You can view the RMON information 

locally on the switch or by using a generic RMON console on a network 

management station (NMS). SNMP does not need to be configured on the 

switch to view the RMON data locally. However, if you use a management 

station to view the RMON data that the switch collects and analyzes, you 

must configure the following SNMP settings:

• Set up the SNMP community string to be used by the SNMP manager at a 

given IP address.

• Specify the network management system IP address or permit 

management access from all IP addresses.

For more information about configuring SNMP, see "Configuring SNMP" on