Which memory buffering method would work best for switching frames from a 1000BASE-T port to a 100Base-T network?

• A. Port-based buffering
• B. Level 1 Cache Buffering
• C. Shared Memory Buffering
• D. Fixed Configuration Buffering

Answer: (C)

This question tests how memory buffering handles a faster input than output when switching frames from a 1 Gbps link to a 100 Mbps link. Because the incoming rate can exceed the outgoing rate, the switch needs room to store frames temporarily. Shared memory buffering uses a common pool of memory that can be allocated to any port as needed, so bursts arriving on the fast side can be buffered and then transmitted over the slower link without dropping frames. This dynamic allocation and reuse of memory makes it versatile for cross-speed switching. In contrast, fixed allocations per port don’t adapt to changing traffic, and a rigid per-port scheme can either waste space or run out of room during bursts. Cache-based buffering focuses on processor caches rather than frame buffering across interfaces, so it doesn’t address the buffering needs of cross-speed paths. Therefore, shared memory buffering is the most suitable approach for this scenario.