Alcatel-Lucent 7750 SR OS - Manual (Page 457)

Cflowd
7750 SR OS Router Configuration Guide Page 457
Specifying Sampling Options in Filter Entries
Packets are matched against filter entries to determine acceptability. With cflowd, only the first
packet of a flow is compared. If the first packet matches the filter criteria, then an entry is added to
the cflowd cache. Subsequent packets in the same flow are also sampled based on the cache entry.
Since a filter can be applied to more than one interface (when configured with a scope
template ), the interface-disable-sample option is intended to enable or disable traffic
sampling on an interface-by-interface basis. The command can be enabled or disabled as needed
instead creating numerous filter versions.
When the cflowd interface option is configured in the config>router> interface
context, the following requirements must be met in order to enable traffic sampling on the specific
interface:
1. Cflowd must be enabled.
2. At least one cflowd collector must be configured and enabled.
3. The interface>cflowd interface option must be selected. For configuration
information, refer to the Filter Policy Overview sections of the 7750 SR OS Router
Configuration Guide.
4. The config>filter>ip-filter>entry>interface-disable-sample option
must be enabled (the default, no interface-disable-sample , must be explicitly
modified to interface-disable-sample ).
5. The filter must be applied to a service or a port.
Filter Configurations
CLI Syntax: config>filter>ip-filter>entry#
[no] filter-sample
[no] interface-disable-sample
When a filter policy is applied to a service or port, sampling can be configured so that traffic
matching the associated IP filter entry is sampled when the IP interface is set to cflowd ACL mode
and the
filter-sample command is enabled. If cflowd is either not enabled (no filter-
sample) or set to the cflowd interface mode, then sampling does not occur.
When the interface-disable-sample command is enabled, then traffic matching the
associated IP filter entry is not sampled if the IP interface is set to cflowd ACL mode.