Switching
4.3 Rate Limiter
The device can limit the rate of message traffic during periods of heavy traffic
flow.
Entering a limit rate for each port specifies the amount of traffic the device is
permitted to transmit and receive.
If the data load transmitted at this port exceeds the maximum load entered,
the device will discard the excess data at this port.
A global setting enables/disables the rate limiter function at all ports.
Note: The limiter functions work exclusively on layer 2 and serve the purpose
of limiting the effects of storms of those frame types (typically broadcasts)
that the Switch floods. The limiter function ignores any protocol information
of higher layers like IP or TCP. This may affect e.g., TCP traffic.
You can minimize this effects by:
applying the limiter function only to particular frame types (e.g., to
broadcasts, multicasts and unicasts with an unlearned destination
address) and excluding unicasts with a learned destination address from
the limitation,
using the egress limiter function instead of the ingress limiter function
because the former cooperates slightly better with TCP's flow control
(reason: frames buffered by the internal switching buffer),
increasing the aging time for learned unicast destination addresses.
Note: Ports that are included in a Link Aggregation
excluded from the rate limitation, regardless of the entries in the "Rate
Limiter" dialog.
96
4.3 Rate Limiter
(see page 158)
are
Release 6.0 07/2010
RM Web