IP175DLF datasheet(37/145 Pages) ETC

37 / 145 page

IP175DLF

Datasheet

37/145

August 22, 2014

IP175DLF-DS-R10.1

Function Description

3.1

Flow Control

IP175DLF supports the standard 802.3X flow control frames on both transmit and receive sides. On the

receive side, if IP175DLF receives a pause control frame, the IP175DLF will defer transmitting next

normal frame; on the transmit side, IP175DLF issues pause control frame to remote station when the

output of the destination port is overflowed. The source address (SA) of pause control frame will be

{IP175DLF OUI (0090C3), port number}. For example, the SA of port 1 pause control frame will be “ 00 90

C3 00 00 01”.

When CoS is enabled, IP175DLF may disable the flow control function for a short term to guarantee the

bandwidth of high priority packets. A port disables its flow control function for 2 ~ 3 seconds when it

receives the highest priority packet. It doesn’t transmit pause frame or jam pattern during the period but it

still responses to pause frame or jam pattern.

IP175DLF’s PHY 0~4 MII register 4.10 can not use to set flow control ability for each port. The flow control

function can be only enabled by pulling up pin 100 (X_EN) or by programming MII register 20.5[1].

3.2

Broadcast Storm Protection

A port of IP175DLF begins to drops broadcast packets if the received broadcast packets are more than

the threshold defined in MII register 20.17~20.19 bq_stm_thr_sel [1:0] in 10ms (100Mbps) or 100ms

(10Mbps).

The function can be enabled by pulling high pin 102 (BF_STM_EN) or programming MII register

20.16[13:8].

3.3

Rate Control

The rate control is provided by applying to port rate control, Multi-Field traffic policy and WFQ scheduling.

IP175DLF use token bucket to measure the traffic to against the traffic profile. The traffic profile is a

predefine traffic rate which contain three parameters: timing interval

1, credit size and burst size. User can

configure desired rate from MII register 21.8-12, except for Multi-Field traffic policy. Configuring rate

parameter of Multi-Field traffic policy is from MII register 26.16-17. When the rate has been configured,

the meter measure the traffic and then against its predefined traffic profile. Switch passes in-of-profile

packets and drop (or shape) out-of-profile packets in ingress (or egress).

1 In ingress port rate control and Multi-Field traffic policy, timing interval parameter is fixed to 1ms.

IP175DLF Datasheet(PDF) 37 Page - List of Unclassifed Manufacturers