What are the two types of memory buffering on switches?

Question

Accepted Answer

Port-based memory queues frames per port (one busy destination can stall a port's whole queue); shared memory pools all frames in a common buffer allocated dynamically, which handles bursts and asymmetric switching better.

Method
Description
Characteristics

Port-Based Memory
Frames stored in queues linked to specific ports
Each port has dedicated buffer; frame waits in that port's queue

Shared Memory
All frames stored in a common memory buffer shared by all ports
Buffer dynamically allocated; supports asymmetric switching

Port-Based Memory:

A single frame can delay transmission of other frames in the same port's queue
Simpler design

Shared Memory:

More flexible - can handle bursts better
Supports asymmetric switching (different bandwidth on different ports)
Example: More bandwidth can be dedicated to a server port (uplink)
Frame can be transmitted from any port without being moved in memory

Go deeper:

Network switch (Wikipedia) — switch architecture and buffering, including how shared-memory designs support asymmetric port speeds.

Method	Description	Characteristics
Port-Based Memory	Frames stored in queues linked to specific ports	Each port has dedicated buffer; frame waits in that port's queue
Shared Memory	All frames stored in a common memory buffer shared by all ports	Buffer dynamically allocated; supports asymmetric switching