10 Network Load Control; Direct Packet Distribution; Learning Mac Addresses; Aging Of Learned Mac Addresses - Hirschmann Greyhound GRS1020 Reference Manual

10 Network load control

The device features a number of functions that reduce the network load:

Direct packet distribution


Multicasts

Rate limiter

Prioritization - QoS

Flow control

10.1 Direct packet distribution
The device reduces the network load with direct packet distribution.
On each of its ports, the device learns the sender MAC address of received data packets. The
device stores the combination "port and MAC address" in its MAC address table (FDB).
By applying the "Store and Forward" method, the device buffers data received and checks it for
validity before forwarding it. The device rejects invalid and defective data packets.
10.1.1

Learning MAC addresses

When the device receives a data packet, it checks whether the MAC address of the sender is
already stored in the MAC address table (FDB). When the MAC address of the sender is unknown,
the device generates a new entry. The device then compares the destination MAC address of the
data packet with the entries stored in the MAC address table (FDB):
The device forwards packets with a known destination MAC address directly to ports that have

already received data packets from this MAC address.
The device floods data packets with unknown destination addresses, that is, the device forwards

these data packets to every port.
10.1.2

Aging of learned MAC addresses

Addresses that have not been detected by the device for an adjustable period of time (aging time)
are deleted from the MAC address table (FDB) by the device. A reboot or resetting of the MAC
address table deletes the entries in the MAC address table (FDB).
UM Config GRS
Release 8.0 09/2019
Network load control
10.1 Direct packet distribution
113