H3C Technologies H3C MSR 5600 - Manual (Page 199)

186
Periodical aging
Periodical aging uses the following methods:
• Inactive flow aging—A flow is considered inactive if 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 entry 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 method makes sure 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 collect the active flow statistics, which can be displayed by the display ip netstream
cache command. The active flow aging method periodically exports the statistics of active flows to
the NetStream server.
Forced aging
To implement forced aging, use one of the following methods:
• Use the reset ip netstream statistics command to age out all NetStream entries in the cache, to
export, and to clear the statistics.
• Use the ip netstream max-entry command to configure whether to age out the entries or disable
creation of a new entry in the cache when the maximum number of entries is reached.
TCP FIN- and RST-triggered aging
For a TCP connection, a session is finished when a packet with a FIN or RST flag is received. If a packet
with a FIN or RST flag is recorded for a flow with the NetStream entry already created, the flow is
immediately aged out, exported, and cleared. 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
always enabled, and it cannot be disabled.
Configuration procedure
To configure flow aging:
Step Command Remarks
1. Enter system view. system-view N/A
2. Configure periodical
aging.
• Set the aging timer for active flows:
ip netstream timeout active minutes
• Set the aging timer for inactive flows:
ip netstream timeout inactive seconds
By default:
• The aging timer for active
flows is 30 minutes.
• The aging timer for
inactive flows is 30
seconds.