BCM5722 Programmer’s Guide
10/15/07
Broadcom Corporation
Page 515 Flow Control Scenario Document 5722-PG101-R
SWITCH BUFFERS RUN LOW
The switch must wait/inhibit transmission to the Client (see Figure 70). During the pause interval, the Server is still sending
packets to the Switch. The Switch will buffer some packets, but will eventually hit an internal threshold; memory will run short.
Since dropping packets is undesirable, the Switch must slow incoming packets from the Server. The duplex mode of the
Server’s connection will dictate how the switch slows traffic. There are two options:
• Jamming (half-duplex)
• Pause frames (full-duplex)
Figure 70: File Transfer Scenario: Speed Buffers Run Low
Ingres
Switch
Client
Port
Server
Port
MAC Sublayer
Port buffers &
memory almost
exhausted
Egres
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