Rate Limiter; Description Of The Rate Limiter - Hirschmann RS20 User Manual

Network Load Control

8.3 Rate Limiter

8.3.1

Description of the 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.
Basic Configuration
Release 6.0 07/2010
8.3 Rate Limiter
137