3com Corporation

Ronit Aizicovich

Sarit Shani Natanson

Haim Rochberger

Golan Schzukin

Lior Katzri

Benny Gershon

Henic Roizman

Raphi Hess

A method of notification and handling of device status changes in MPOA enabled ATM based networks. In a first method notification of changes in device status configuration are provided by selectively releasing one or more Data Direct VCs that were previously established be LECs connecting MPOA Servers and MPOA Clients. An MPOA Server, upon detecting a change to its device configuration status, releases the Data Direct VCs connecting its associated LEC to known MPSs and MPCs that are neighbors to it. All MPOA devices for which a Data Direct VC was released delete all LE_ARP cache entries associated with the ATM destination of the released Data Direct VC. In a second method, each MPOA device periodically sends keep alive messages as targetless LE_ARP messages having a time to live TLV appended. An MPOA device receiving the keep alive message, refreshes (i.e., restarts) a validation timer for each association made by the corresponding MPOA identification TLV. If the validation timer expires before being refreshed, the MPOA device deletes all associations previously made by the corresponding MPOA identification TLV.

Method of MPOA status change notification

An apparatus for and a method of learning MAC addresses in a Local Area Network (LAN) Emulation (LANE) network implemented over an Asynchronous Transfer Mode (ATM) network. The LEC or LES is adapted to detect when the ATM address associated with a MAC address is no longer valid. Once an invalid ATM address is detected the existing entry can be updated or deleted. A LEC_ID table holding LEC_ID to ATM address bindings is created. Each frame received by the LEC is sniffed in order to find mismatches between the ATM address and the LEC_ID. Optionally, an LE_ARP request message can be forwarded to the LES for learning the new binding. If the MAC address is not found in the LE_ARP table, an entry can be created and added to the table. In another embodiment, the LES is adapted to detect when the MAC to ATM address binding stored in the internal LE_ARP cache is no longer valid. The LE_ARP table is populated by examining LE_ARP request and response sent and received by the LEC. Upon detection of a mismatch in LEC_ID, the LES can delete or update the entry. The LES generates and sends a LE_NARP or targetless LE_ARP request message which finctions to notify the LEC in the ELAN of a changed MAC to ATM address binding.

Apparatus for and method of learning MAC addresses in a LAN emulation network

A novel BUS entity utilizing the forwarding engine in a conventional LAN switch incorporating an ATM interface. The forwarding engine is adapted to assemble Ethernet frames from ATM cells and to segment Ethernet frames back to ATM cells. The switching fabric in a conventional LAN switch is adapted to perform the segmentation and re-assembly (SAR) function of the BUS whereby ATM cells are assembled into Ethernet frames, switched and segmented back to ATM cells. In operation, one or more Multicast Send VCCs transmit traffic destined for the BUS to the modified LAN switch of the present invention. The switching fabric is configured to switch the received traffic to an appropriate outbound Etheret port. The outbound Ethernet port is looped backed to itself and input to the switching fabric. Switching fabric is configured to output the traffic to the appropriate Multicast Forward VCC for distribution to the LECs.

LAN emulation broadcast and unknown server

Growing community of inventors

Ramat Gan, Israel

Ronit Aizicovich