High speed cache management unit for use in a bridge/router
US5978951A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1997 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Sep 11, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2012/5652
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method and cache management for a bridge or bridge/router providing high-speed, flexible address cache management. The unit maintains a network address cache and an age table, searches the cache for layer 2 and layer 3 addresses from received frame headers, and returns address search results. The unit includes an interface permitting processor manipulation of the cache and age table, and supports a 4-way set associative cache to store the network addresses. A plurality of functions implemented in hardware enables software manipulation of the associated cache. Four cache operating modes are selectable. The unit can identify and select destination ports within a Load Balanced Port Group for frame forwarding. The unit utilizes Virtual LAN identification in conjunction with a MAC address for lookup in the cache. A cyclic redundancy code for each address to be looked up in the cache is used as an index into the cache. If a cache thrash rate exceeds a predetermined threshold, CRC table values can be rewritten. Four time-sliced cache lookup units are provided, each consisting of a cache lookup controller for comparing a received network address to an address retrieved from an identified…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.