Alcatel-Lucent 7750 SR-OS, Configuration Manual

Page: 632 / 674

Page 632 7750 SR OS Router Configuration Guide
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.
To enable for filtr traffic sampling, the following requirements must be met::
1. Cflowd must be enabled globally.
2. At least one cflowd collector must be configured and enabled.
3. On the IP interface being used, the interface>cflowd acl option must be selected. (See
Interfcace Configuration) For configuration information, refer to the IP Router
Confguration Overview section of the 7750 SR OS Router Configuration Guide
.
4. On the IP filter being used, the entry>filter-sample option must be explicitly enabled for
the entries matching the traffic that should be sampled. The default is no filter-sample .
(See Filter Configuration for more information).
5. The filter must be applied to a service or a network interface. The service or port must be
enabled and operational.
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 a network interface, 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.