NETZÜBERGANGSEINRICHTUNG MIT EINER ADAPTIVEN BRÜCKE ZUR EFFIZIENTEN ABBILDUNG VON ETHERNET PAKETEN ÜBER EINEM ATM-BASIERTEN BREITBAND ZUGANGSNETZ

摘要

A network interface for mapping local ethernet traffic onto an ATM-based broadband access network includes an adaptive MAC-level bridge that employs a fast algorithm for filtering outgoing ethernet packets destined only for local devices on the same ethernet. The network interface reads outgoing packets received on a respective local ethernet segment, using the last byte of the MAC destination address of the packet header to index into a hash table of a linked list containing the first five bytes of respective stored MAC addresses of devices located on the subscriber ethernet segment. If the destination address exists in the linked list, the ethernet packet is dropped, since it belongs to the subscriber LAN segment and is not meant for further upstream transmission over the broadband access network. Since only the last byte of the destination address is used for hashing, a relatively small table of only two-hundred fifty-five entries can be used to index into the remaining five bytes of the respective stored MAC addresses, wherein the linked list keeps track of collisions on addresses linked to the same hash value.