User guide

Filter Details MAC-ID

Filtering the MAC-ID, the MAC-IP and IP-Header is implemented to reduce the overhead in

comparing the received frames for the cpu in embedded systems

 MAC-ID filter

Each device has to have it's own MAC-ID, which has to be loaded into the GMACII-core by software

(MAC ID low - the last 32 bit and MAC ID high - the first 16 bit).

The MAC-ID filter decodes the first 6 bytes of each received frame (called Destination Address) and

compares to that loaded value.

If all 48bit match, the received frame is accepted.

Additionally a Destination Address of "FF FF FF FF FF FF" is accepted as broadcast.

 MCMAC-ID filter for Multicast (Advanced Features ON):

− For receiving multicast frames we have an additional filter set. This filter works:

 In parallel to the MAC-ID filter, so we can receive both kinds of destination IDs

 Or work as SRC Address filter when not used as Multicast

− filtering the SRC address can increase the security level, example:

− after a communication is set up, the local software can load the MCMAC-ID with the SRC address of the partner, and enable that

filter, so only IP communication with that partner gets processed, other partners can not get through

− Additionally a Destination Address of “01 00 5E 0xxxxxxx XX XX" is accepted as multicast-broadcast.

 01-00-5e-00-00-00 … 01-00-5e-7f-ff-ff