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参数资料
| 型号： | KS8993-EVAL |
| 厂商： | Micrel Inc |
| 文件页数： | 10/35页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL EXPERIMENT FOR KS8993 |
| 标准包装： | 1 |
| 相关产品： | KS8993I-ND - IC SWITCH 10/100 3PORT 128PQFP KS8993-ND - IC SWITCH 10/100 3PORT 128PQFP |
| 其它名称： | 576-1011 |
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KS8993
Micrel
KS8993
18
May 2005
Functional Overview: Switch Core
Address Look-Up
The internal look-up table stores MAC addresses and their associated information. It contains 1K full CAM with 48-bit address
plus switching information. The KS8993 is guaranteed to learn 1K addresses and distinguishes itself from hash-based look-
up tables which, depending on the operating environment and probabilities, may not guarantee the absolute number of
addresses it can learn.
Learning
The internal look-up engine will update its table with a new entry if the following conditions are met:
The received packet’s SA does not exist in the look-up table.
The received packet is good; the packet has no receiving errors, and is of legal length.
The look-up engine will insert the qualified SA into the table, along with the port number, time stamp. If the table is full, the
last entry of the table will be deleted first to make room for the new entry.
Migration
The internal look-up engine also monitors whether a station is moved. If it happens, it will update the table accordingly.
Migration happens when the following conditions are met:
The received packet’s SA is in the table but the associated source port information is different.
The received packet is good; the packet has no receiving errors, and is of legal length.
The look-up engine will update the existing record in the table with the new source port information.
Aging
The look-up engine will update time stamp information of a record whenever the corresponding SA appears. The time stamp
is used in the aging process. If a record is not updated for a period of time, the look-up engine will then remove the record from
the table. The look-up engine constantly performs the aging process and will continuously remove aging records. The aging
period is approximately 300 seconds
±75 sec. This feature can be enabled or disabled by external pull-up or pull-down resistors.
If aging is disabled and look-up table is full, KS8993 will remove the largest address in the table which has been sorted by
the binary search.
Forwarding
The KS8993 will forward packets as follows:
If the DA look-up results is a “match”, the KS8993 will use the destination port information to determine where the
packet goes.
If the DA look-up result is a “miss”, the KS8993 will forward the packet to all other ports except the port that received
the packet.
All the multicast and broadcast packets will be forwarded to all other ports except the source port.
The KS8993 will not forward the following packets:
Error packets. These include framing errors, FCS errors, alignment errors, and illegal size packet errors.
802.3x pause frames. The KS8993 will intercept these packets and do the appropriate actions.
“Local” packets. Based on destination address (DA) look-up. If the destination port from the look-up table matches
the port where the packet was from, the packet is defined as “local”.
Switching Engine
The KS8993 has a very high performance switching engine to move data to and from the MAC’s, packet buffers. It operates
in store and forward mode, while the efficient switching mechanism reduces overall latency.
The KS8993 has an internal buffer for frames that is 16kx32 (64kB). This resource is shared between the three ports. Buffer
sizing per port can be programmed at system reset time by using the unmanaged program mode (I/O strapping).
Each buffer is sized at 128B and therefore there are a total of 512 buffers available. A per port maximum can be set at 170
buffers (equal allocation). There is also an adaptive mode that reacts to port traffic. In the adaptive mode any given port may
use up to 256 buffers provided that the other ports are lightly loaded. In the event of heavier loading on other ports the limit
is 170 buffers.
MAC (Media Access Controller) Operation
The KS8993 strictly abides by IEEE 802.3 standard to maximize compatibility and interoperability with other vendors.
Inter Packet Gap (IPG)
If a frame is successfully transmitted, the 96 bit time IPG is measured between the two consecutive MTXEN. If the current
packet is experiencing collision, the 96 bit time IPG is measured from MCRS and the next MTXEN.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| KS8993F | 功能描述:IC CONV MED 10/100 3PORT 128PQFP RoHS:是 类别:集成电路 (IC) >> 专用 IC 系列:* 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- 类型:调帧器 应用:数据传输 安装类型:表面贴装 封装/外壳:400-BBGA 供应商设备封装:400-PBGA（27x27） 包装:散装 |
| KS8993F-A1 | 功能描述:IC CONV MED 10/100 3PORT 128PQFP RoHS:否 类别:集成电路 (IC) >> 专用 IC 系列:* 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- 类型:调帧器 应用:数据传输 安装类型:表面贴装 封装/外壳:400-BBGA 供应商设备封装:400-PBGA（27x27） 包装:散装 |
| KS8993FA5 | 功能描述:IC SWITCH 3-PORT 10/100 128-PQFP RoHS:否 类别:集成电路 (IC) >> 专用 IC 系列:* 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- 类型:调帧器 应用:数据传输 安装类型:表面贴装 封装/外壳:400-BBGA 供应商设备封装:400-PBGA（27x27） 包装:散装 |
| KS8993F-EVAL | 功能描述:EVAL KIT EXPERIMENTAL KS8993F RoHS:否 类别:编程器，开发系统 >> 评估演示板和套件 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- 主要目的:电源管理，电池充电器 嵌入式:否 已用 IC / 零件:MAX8903A 主要属性:1 芯锂离子电池 次要属性:状态 LED 已供物品:板 |
| KS8993FL | 功能描述:IC CONV MED 10/100 SGL 128PQFP RoHS:否 类别:集成电路 (IC) >> 专用 IC 系列:* 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- 类型:调帧器 应用:数据传输 安装类型:表面贴装 封装/外壳:400-BBGA 供应商设备封装:400-PBGA（27x27） 包装:散装 |
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