- 您现在的位置：买卖IC网 > PDF目录300164 > ZL50418GKG2 (CONEXANT SYSTEMS) DATACOM, LAN SWITCHING CIRCUIT, PBGA553 PDF资料下载
参数资料
| 型号： | ZL50418GKG2 |
| 厂商： | CONEXANT SYSTEMS |
| 元件分类： | 网络接口 |
| 英文描述： | DATACOM, LAN SWITCHING CIRCUIT, PBGA553 |
| 封装： | 37.50 X 37.50 MM, 2.33 MM HEIGHT, LEAD FREE, MS-034, HSBGA-553 |
| 文件页数： | 118/155页 |
| 文件大小： | 1928K |
| 代理商： | ZL50418GKG2 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页第82页第83页第84页第85页第86页第87页第88页第89页第90页第91页第92页第93页第94页第95页第96页第97页第98页第99页第100页第101页第102页第103页第104页第105页第106页第107页第108页第109页第110页第111页第112页第113页第114页第115页第116页第117页当前第118页第119页第120页第121页第122页第123页第124页第125页第126页第127页第128页第129页第130页第131页第132页第133页第134页第135页第136页第137页第138页第139页第140页第141页第142页第143页第144页第145页第146页第147页第148页第149页第150页第151页第152页第153页第154页第155页
ZL50418
Data Sheet
65
Zarlink Semiconductor Inc.
8.10.2
Multicast Flow Control
In unmanaged mode, flow control for multicast frames is triggered by a global buffer counter. When the system
exceeds a programmable threshold of multicast packets Xoff is triggered. Xon is triggered when the system returns
below this threshold.
In managed mode, per-VLAN flow control is used for multicast frames. In this case, flow control is triggered by
congestion at the destination. How so? The ZL50418 checks each destination to which a multicast packet is
headed. For each destination port, the occupancy of the lowest-priority transmission multicast queue (measured in
number of frames) is compared against a programmable congestion threshold. If congestion is detected at even
one of the packet’s destinations then Xoff is triggered.
In addition, each source port has a 26-bit port map recording which port or ports of the multicast frame’s fanout
were congested at the time Xoff was triggered. All ports are continuously monitored for congestion and a port is
identified as uncongested when its queue occupancy falls below a fixed threshold. When all those ports that were
originally marked as congested in the port map have become uncongested, then Xon is triggered and the 26-bit
vector is reset to zero.
The ZL50418 also provides the option of disabling VLAN multicast flow control.
Note: If per-Port flow control is on, QoS performance will be affected.
8.11
Mapping to IETF DiffServ Classes
The mapping between priority classes discussed in this chapter and elsewhere is shown below.
Table 11 - Mapping between ZL50418 and IETF DiffServ Classes for Gigabit Ports
Table 12 - Mapping between ZL50418 and IETF DiffServ Classes for 10/100 M Ports
As Table 11 illustrates, P7 is used solely for network management (NM) frames. P6 is used for expedited forwarding
service (EF). Classes P2 through P5 correspond to an assured forwarding (AF) group of size 4. Finally, P0 and P1
are two best effort (BE) classes.
For 10/100 M ports, the classes of Table 11 are merged in pairs, as shown in Table 12 — one class corresponding
to NM+EF, two AF classes, and a single BE class.
Features of the ZL50418 that correspond to the requirements of their associated IETF classes are summarized in
the table below.
ZL50418
P7
P6
P5
P4
P3
P2
P1
P0
IETF
NM
EF
AF0
AF1
AF2
AF3
BE0
BE1
ZL50418
P3
P2
P1
P0
IETF
NM+EF
AF0
AF1
BE0
Network management (NM) and
Expedited forwarding (EF)
Global buffer reservation for NM and EF
Shaper for EF traffic on Gigabit ports
Option of strict priority scheduling
No dropping if admission controlled
相关PDF资料 |
PDF描述 |
|---|---|
| ZL50418/GKC | DATACOM, LAN SWITCHING CIRCUIT, PBGA553 |
| ZL50418GKG2 | DATACOM, LAN SWITCHING CIRCUIT, PBGA553 |
| ZLW-2-B | 1 MHz - 1000 MHz RF/MICROWAVE DOUBLE BALANCED MIXER, 9.5 dB CONVERSION LOSS-MAX |
| ZMG71W | SINGLE COLOR LED, GREEN |
| ZMM5228/D1 | 3.9 V, 0.5 W, SILICON, UNIDIRECTIONAL VOLTAGE REGULATOR DIODE |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ZL51B | 制造商:YEASHIN 制造商全称:YEASHIN 功能描述:500 mW DO-35 Hermetically Sealed Glass Zener Voltage Regulators |
| ZL56B | 制造商:YEASHIN 制造商全称:YEASHIN 功能描述:500 mW DO-35 Hermetically Sealed Glass Zener Voltage Regulators |
| ZL5V1B | 制造商:YEASHIN 制造商全称:YEASHIN 功能描述:500 mW DO-35 Hermetically Sealed Glass Zener Voltage Regulators |
| ZL5V6B | 制造商:YEASHIN 制造商全称:YEASHIN 功能描述:500 mW DO-35 Hermetically Sealed Glass Zener Voltage Regulators |
| ZL60001 | 制造商:ZARLINK 制造商全称:Zarlink Semiconductor Inc 功能描述:High speed 2.5 Gbps 850 nm VCSEL |
发布紧急采购，3分钟左右您将得到回复。