Configuring netstream flow aging, Flow aging approaches, Periodical aging – H3C Technologies H3C MSR 50 User Manual

Page 114: Forced aging, Tcp fin- and rst-triggered aging

Advertising
background image

To configure MPLS-aware NetStream:

Step Command

Remarks

249.

Enter system view.

system-view

N/A

By default, no statistics about MPLS
packets are counted and exported.
The command of ip netstream mpls

[ label-positions { label-position1
[ label-position2 ]

[ label-position3 ] } ] [ no-ip-fields ]

enables both IPv4 and IPv6
NetStream of MPLS packets.

250.

Count and export

statistics on MPLS

packets.

ip netstream mpls [ label-positions
{ label-position1 [ label-position2 ]

[ label-position3 ] } ] [ no-ip-fields ]

Configuring NetStream flow aging

Flow aging approaches

The following types of NetStream flow aging are available:

Periodical aging

Forced aging

TCP FIN- and RST-triggered aging (automatically triggered if a TCP connection is terminated)

Periodical aging

Periodical aging uses the following approaches:

Inactive flow aging—A flow is considered inactive if its statistics have not been changed, which
means no packet for this NetStream entry arrives in the time specified by the ip netstream timeout

inactive command. The inactive flow entry remains in the cache until the inactive timer expires. Then
the inactive flow is aged out and its statistics, which can no longer be displayed by the display ip

netstream cache command, are sent to the NetStream server. The inactive flow aging makes sure

that the cache is big enough for new flow entries.

Active flow aging—An active flow is aged out when the time specified by the ip netstream timeout
active command is reached, and its statistics are exported to the NetStream server. The device

continues to count the active flow statistics, which can be displayed by the display ip netstream
cache command. The active flow aging exports the statistics of active flows to the NetStream server.

Forced aging

Use the reset ip netstream statistics command to age out all NetStream entries in the cache and to clear

the statistics. This is forced aging.

TCP FIN- and RST-triggered aging

For a TCP connection, when a packet with a FIN or RST flag is sent out, it means that a session is finished.
If a packet with a FIN or RST flag is recorded for a flow with the NetStream entry already created, the

flow is aged out immediately. However, if the packet with a FIN or RST flag is the first packet of a flow,

a new NetStream entry is created instead of being aged out. This type of aging is enabled by default,

and it cannot be disabled.

101

Advertising