Netstream overview, Basic concepts of netstream, What is a flow – H3C Technologies H3C SecBlade NetStream Cards User Manual
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NetStream overview
This chapter includes these sections:
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NetStream sampling and filtering
Conventional traffic statistics collection methods, like SNMP and port mirroring, cannot provide precise
network management because of inflexible statistical methods or high cost (dedicated servers are
required). This calls for a new technology to collect traffic statistics.
NetStream provides statistics on network traffic flows and can be deployed on access, distribution, and
core layers.
The NetStream technology implements the following features:
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Accounting and billing—NetStream provides detailed data about the network usage based on the
resources such as lines, bandwidth, and time periods. The Internet service providers (ISPs) can use
the data for billing based on time period, bandwidth usage, application usage, and quality of
service (QoS). The enterprise customers can use this information for department chargeback or cost
allocation.
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Network planning—NetStream data provides key information, for example the autonomous system
(AS) traffic information, for optimizing the network design and planning. This helps maximize the
network performance and reliability when minimizing the network operation cost.
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Network monitoring—Configured on the Internet interface, NetStream allows for traffic and
bandwidth utilization monitoring in real time. Based on this, administrators can understand how the
network is used and where the bottleneck is, better planning the resource allocation.
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User monitoring and analysis—The NetStream data provides detailed information about network
applications and resources. This information helps network administrators efficiently plan and
allocate network resources, and ensure network security.
Basic concepts of NetStream
What is a flow
NetStream is an accounting technology to provide statistics on a per-flow basis.
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An IPv4 flow is defined by the 7-tuple elements: destination address, source IP address, destination
port number, source port number, protocol number, type of service (ToS), and inbound or outbound
interface. The 7-tuple elements define a unique flow.
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An IPv6 flow is defined by the 8-tuple elements: destination address, source IP address, destination
port number, source port number, protocol number, traffic class, flow label, and inbound or
outbound interface. The 8-tuple elements define a unique flow.