LAN9303 Datasheet, PDF (75/366 Pages) SMSC Corporation – Small Form Factor Three Port 10/100 Managed Ethernet Switch with Single MII/RMII/Turbo MII

Small Form Factor Three Port 10/100 Managed Ethernet Switch with Single MII/RMII/Turbo MII
Datasheet
Table 6.2 Spanning Tree States (continued)
Port State
01 - Blocking
01 - Listening
10 - Learning
00 - Forwarding
Hardware Action
Software Action
Received packets on the port are
discarded unless overridden.
Transmissions to the port are blocked
unless overridden.
Learning on the port is disabled.
The MAC Address Table should be programmed
with entries that the host CPU needs to receive
(e.g. the BPDU address). The static and override
bits should be set.
The host CPU may send packets to the port in this
state. Only packets with STP override will be
transmitted.
Note: There is no hardware distinction between
the Blocking and Listening states.
Received packets on the port are
discarded unless overridden.
Transmissions to the port are blocked
unless overridden.
Learning on the port is disabled.
The MAC Address Table should be programmed
with entries that the host CPU needs to receive
(e.g. the BPDU address). The static and override
bits should be set.
The host CPU may send packets to the port in this
state. Only packets with STP override will be
transmitted.
Received packets on the port are
discarded unless overridden.
Transmissions to the port are blocked
unless overridden.
Learning on the port is enabled.
The MAC Address Table should be programmed
with entries that the host CPU needs to receive
(e.g. the BPDU address). The static and override
bits should be set.
The host CPU may send packets to the port in this
state. Only packets with STP override will be
transmitted.
Received packets on the port are
forwarded normally.
Transmissions to the port are sent
normally.
Learning on the port is enabled.
The MAC Address Table should be programmed
with entries that the host CPU needs to receive
(e.g. the BPDU address). The static and override
bits should be set.
The host CPU may send packets to the port in this
state.
6.4.6
Ingress Flow Metering and Coloring
Hardware ingress rate limiting is supported by metering packet streams and marking packets as either
Green, Yellow, or Red according to three traffic parameters: Committed Information Rate (CIR),
Committed Burst Size (CBS), and Excess Burst Size (EBS). A packet is marked Green if it does not
exceed the CBS, Yellow if it exceeds to CBS but not the EBS, or Red otherwise.
Ingress flow metering and coloring is enabled via the Ingress Rate Enable bit in the Switch Engine
Ingress Rate Configuration Register (SWE_INGRSS_RATE_CFG). Once enabled, each incoming
packet is classified into a stream. Streams are defined as per port (3 streams), per priority (8 streams),
or per port & priority (24 streams) as selected via the Rate Mode bits in the Switch Engine Ingress
Rate Configuration Register (SWE_INGRSS_RATE_CFG). Each stream can have a different CIR
setting. All streams share common CBS and EBS settings. CIR, CBS, and EBS are programmed via
the Switch Engine Ingress Rate Command Register (SWE_INGRSS_RATE_CMD) and Switch Engine
Ingress Rate Write Data Register (SWE_INGRSS_RATE_WR_DATA).
Each stream is metered according to RFC 2697. At the rate set by the CIR, two token buckets are
credited per stream. First, the Committed Burst bucket is incremented up to the maximum set by the
CBS. Once the Committed Burst bucket is full, the Excess Burst bucket is incremented up to the
maximum set by the EBS. The CIR rate is specified in time per byte. The value programmed is in
SMSC LAN9303/LAN9303i
75
DATASHEET
Revision 1.3 (08-27-09)