Remapping of ATM cells for multicast transmission
US5917819A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1996 |
| Grant date | Jun 29, 1999 |
| Priority date | — |
| Expiry date | Apr 26, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L49/309
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Improved methods and apparatus are disclosed for remapping Asynchronous Transfer Mode ("ATM") cells in an ATM switch to convert a single Virtual Path Identifier ("VPI")/Virtual Connection Identifier ("VCI") address pair to multiple outgoing VPI/VCI pairs for multicast transmission. An incoming cell is examined to determine the ports through which the cell will exit and a local header is generated which includes a field specifying the I/O modules ("IOMs") through which the cell will exit. The VPI/VCI pair of an incoming multicast cell is mapped to a global multicast identifier ("MID") which is written into the local header. The cell, including the local header is then forwarded to the IOMs specified in the header. A first lookup table on each IOM is employed to provide a port bitmask indexed by MID to direct the cell to the previously identified ports, and to map the MID into a connection identifier ("CID"). A second lookup table is employed to map the CID provided from the first table to a destination VPI/VCI. The second table is shared among all ports on the IOM. Memory utilization efficiency is improved by using global MIDs and by distinguishing multiport-multicast cells from sin…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.