Ethernet 技術研討林文宗明新科技大學資訊工程學系助理教授工研院資通所無線通訊技術組顧問麟瑞科技股份有限公司技術顧問

Ethernet 技術研討林文宗明新科技大學資訊工程學系助理教授工研院資通所無線通訊技術組顧問麟瑞科技股份有限公司技術顧問
摩鐵科技股份有限公司執行顧問清華大學資訊工程系博士

(C) All rights reserved by Assistant Professor Wen-Tsung Lin.
Agenda Ethernet 演進歷程 Ethernet LAN Architecture CSMA/CD MAC運作原理 Layer Management PLS and AUI (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Ethernet 演進歷程

Ethernet 演進歷程 (I) Ethernet 發展至今差不多 30 年,在 1973 年時由Xerox(全錄)公司的 PARC, Palo Alto Research Center (帕羅奧托研究中心) 研發設計推出的第一個區域網路系統,隨即由計劃負責人 Metcalfe 博士命名為 Ethernet,命名的含義是 Ether 和 Network 兩字的組合(在早期Ether 是假想為用來傳遞電磁波的物質,當然後來證實是不存在的), 剛推出之時的 Ethernet 頻寬僅僅只有 2.94Mbps, 而且只於公司內部使用, 並沒有把他商業化。一直到1982年, 由 DEC、Intel 和 Xerox 組成的 DIX 聯盟發表了 Ethernet Version 2 規格(簡稱EV2), 將頻寬提升為10Mbps, 正式將Ethernet 投入市場, 推出的產品為「10Base5 Ethernet」, 之後 IEEE 也根據 EV2 的內容略加修改後在1983年正式通過了802.3 CSMA/CD 規格。 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Ethernet 演進歷程 (II) 10Base5 Ethernet 採用 RG11 A/U 同軸電纜為傳輸介質,電纜的兩端必須接上 50 歐姆終端電阻, 由終端電阻到另一個終端電阻之間的範圍稱為一個 Segment (區段), 每段 Segment 可達 500 公尺, 最多可連接 100 部電腦, 由於這是第一個標準化的Ethernet, 也被稱為「標準乙太網路」。由於 10Base5 佈線不易且成本過高, 於是 3Com 公司推出了改良型產品,10Base2 Ethernet, 改用較細的 RG58 A/U 同軸電纜當作傳輸介質, 電纜的兩端一樣要接上 50 歐姆終端電阻, 兩終端電阻之間的範圍稱為 Segment, 但是最大長度縮減為185 公尺, 每個 segment 最多可連接 30 部電腦, 雖然區段縮小, 連接的電腦數目也減少, 但是因為施工容易, 材料價格低廉等優點逐步淘汱掉第一代的 10Base5 Ethernet。 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Ethernet 演進歷程 (III) 不管是10Base5 還是 10Base2 都有以下兩個缺點：網路的任何一處斷線, 都會導致整個網路停擺,而且追查斷線點較為困難若有電腦要移動位置, 佈線路徑可能需要大幅修正因為管理維護上的不便促使了新一代乙太網路 10BaseT Ethernet 的誕生, 10BaseT Ethernet 採用 UTP (Unshielded Twisted Pair, 無遮蔽式雙絞線)為傳輸介質, 所有的電腦都透過 Hub 互相連接, 電腦到Hub 的最大長度為 100 公尺。 10BaseT Ethernet 具有以下優點：每部電腦都獨立連接到 Hub, 如果電腦或線路發生問題, 只會影響本身這一段的線路, 不會影響其他電腦的運作從Hub的燈號狀況反應即可判斷哪段線路故障,維護比較容易移動電腦時不必改變整體佈線路徑, 只需更動局部佈線路徑即可 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Ethernet 演進歷程 (IV) 提高網路傳輸效益最直接的方法就是增加頻寬, 在 Ethernet 服務 10 年之後, 在1995 年 IEEE 發表了 IEEE 802.3u Fast Ethernet 標準, 其中定義了 3 種 100 Mbps Ethernet 規格,摘要如下： 100BaseTX 100BaseT4 100BaseFX 100BaseT2 傳輸介質 Cat5 以上的UTP線 Cat3 以上的UTP線光纖 (Optical fiber) 所需傳輸線數目 2對 4對相關標準 802.3u 802.3y (1997) 備註和 10BaseT 系統相容 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Ethernet 演進歷程 (V) IEEE 在 1998 年通過 802.3z 1000 Mbps Ethernet 標準,因為是1000 Mbps,這個 Ethernet 也通稱為 Gigabit Ethernet, 在緊接著在 2002 年推出 802.3ae 10Gbps 也就是10000 Mbps的標準, 不過由於 Giga 級的乙太網路設備並不常見, 價格也顯得比較昂貴, 目前主要用途還是充當網路的骨幹線路。 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Ethernet 規格列表代碼 IEEE規格標準標準通過年份頻寬使用線材 10Base5 802.3 1983 10 Mbps
粗同軸電纜 10Base2 802.3a 1988 細同軸電纜 10BaseT 802.3i 1990 Cat3以上的UTP線 10BaseF 802.3j 1992 光纖 100BaseTX 802.3u 1995 100 Mbps Cat5以上的UTP線 100BaseT4 100BaseFX 100BaseT2 802.3y 1997 1000BaseSX 802.3z 1998 1000 Mbps 1000BaseLX 1000BaseCX 特殊同軸電纜 1000BaseT 802.3ab 1999 10GBase-SR 802.3ae 2002 10Gbps 10GBase-LX4 10GBase-LR 10GBase-LW 10GBase-SW 10GBase-ER 10GBase-EW

Ethernet LAN Architecture

Ethernet Architecture
(C) All rights reserved by Assistant Professor Wen-Tsung Lin.

802.3 LAN Model PCS PMA PMD Reconciliation Medium PLS MAC MAC Control (Option) LLC Higher Layers MDI AUI MII GMII 1Mbps, 10Mbps Mbps Mbps Mbps Physical Data Link Network Transport Session Presentation Application PHY MAU (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Terminologies AUI – Attachment Unit Interface MDI – Medium Dependent Interface MII – Media Independent Interface GMII – Gigabit Media Independent Interface MAU – Medium Attachment Unit PLS – Physical Layer Signaling PCS – Physical Coding Sublayer PMA – Physical Medium Attachment PHY – Physical Layer Device PMD – Physical Medium Dependent (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Gigabit Ethernet Repeater
MAC MAC Control (Option) LLC Higher Layers 1000 Mbps Link Segment Physical Data Link Network Transport Session Presentation Application PHY PCS PMA PMD Medium MDI GMII Reconciliation 1000 Mbps 基頻集線器 Link Segment 1000 Mbps 基頻集線器組 ISO 參考模式 CSMA/CD 網路 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

802.3 CSMA/CD 簡介

典型的 CSMA/CD 網路傳輸媒介：同軸電纜、無遮蔽式雙絞線或光纖。傳輸速率：10Mbps 。無優先權，廣播式傳輸。不提供保證傳輸延遲之服務。高負載時，頻寬使用率 (throughput) 低。網路容錯性高，每一工作站之連結栓為被動元件。 A C E B D F 同軸電纜收發器電纜終端器收發器 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

802.3 Ethernet Frame format , , 位元組 Preamble SFD DA SA LEN LLC PAD FCS Preamble: ( ) for Synchronization SFD: Start Frame Delimiter ( ) DA: Destination Address SA: Source Address Length: Length of LLC-Frame LLC-Frame: Up to 1500 bytes PAD: Padding when LLC-Frame < 46 bytes FCS: Frame Check Sequence (CRC-32) MAC訊框大小 -- from DA to FCS Min 64 bytes to distinguish from collision Max 1518 bytes to prevent dominating bandwidth (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

網路卡位址 (MAC Address) I/G U/L 15-位元地址 46-位元地址 I/G = 0 Individual Address （個別地址） I/G = 1 Group Address （群體地址） U/L = 0 Globally Administered Address （整體性地址） U/L = 1 Locally Administered Address （區域性地址） (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

CSMA/CD 協定(I) 步驟 1：傳輸前先監聽網路電纜上是否有訊號在傳送(carrier sense multiple access)。若沒有，則可立即將訊框(frame)傳送出去。若有，則繼續監聽至網路電纜上無訊號在傳送時再將訊框傳送出去(1-堅持法) 。 p-堅持：機率 p 繼續監聽。 0-堅持：不繼續監聽。 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

CSMA/CD 協定(II) 步驟 2：在傳送訊框的同時，也要監聽網路電纜上的信號一段時間 (51.2us) ，看看是否發生碰撞(carrier detection)。若發生碰撞，則立即停止傳送訊框，並改傳送一個擾亂信號 (Jamming signal、32-bit)，強迫造成更嚴重的衝撞，使每一個參與碰撞的工作站都能偵測到碰撞，然後再各自等待一段隨機延遲時間，再由步驟1重新開始 (backoff 、東山再起) 。若未發生碰撞，則表示該訊框傳送成功。 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

流程圖 1-堅持 0-堅持 P-堅持傳送訊框組成訊框, i=1 線上有訊號發生衝撞送出擾亂訊號傳送完畢 i > 16 Y
N i = i + 1 計算延遲時間等待延遲時間傳送成功傳送失敗接收訊框開始接收接收完畢訊框過短（衝撞）位址辨識成功訊框錯誤檢查碼正確尚有多餘位元對齊錯誤長度欄位內容正確刪除訊框頭尾長度錯誤 1-堅持 0-堅持 P-堅持

基頻 CSMA/CD 之碰撞堅聽時間假設 A, B 為距離最遠之兩工作站
a = 0.5 SLOT TIME t0 t0+a-e t0+0.5 B A t0+1 =2a =51.2us 衝撞Ａ開始傳送訊框Ｂ開始傳送訊框Ｂ偵測出衝撞Ａ偵測出衝撞

元件整體延遲穩定延遲啟動延遲元件數訊號來回傳遞最長延遲 46.38us 編碼器 0.1us 0.1us 5 5 2.0us
收發器電纜 5.13ns/公尺 0 300公尺 300公尺 3.08us 收發器（傳送路徑） 0.05us 0.3us us 收發器（接收路徑） 0.05us 0.6us us 收發器（衝撞路徑） 0 0.9us us 同軸電纜 4.33ns/公尺公尺 1500公尺 12.99us 半訊號增益器間電纜 5.13ns/公尺公尺 1000公尺 10.26us 電纜驅動器 0.1us us 電纜接收器 0.1us us 訊號增益器（增益路徑） 0.2us 0.4us us 訊號增益器（衝撞路徑） 0.2us 0.2us us 載波感測 us us 衝撞偵測 us us 訊號上升時間 0 0.1us us （至 70% 於500公尺處）訊號上升時間（由 50% 0 2.0us us 至 94% 於 500公尺處）衝撞分割 us us 穩定延遲啟動延遲前進路徑元件數整體延遲回程路徑訊號來回傳遞最長延遲 us

CSMA/CD 之碰撞處理(I) Collision Handling
Binary Exponential Backoff Algorithm(BEBA)： k = MIN(n,10)，n 為碰撞次數 (n<=16) T: 第 n 次碰撞之延遲時間(單位: slot time)， 0 <= T< 2k 第一次: 0,1 第二次: 0,1,2,3 第三之: 0,1,2,3,4,5,6,7 第十次以後: 0,1,2, ..., 1023 Slot time=51.2 us >網路上最遠二個工作站來回一次之延遲時間。在這段時間內，可傳送64個位元組資料)。 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

CSMA/CD 之碰撞處理(II) Collision Handling
BEBA之缺點： Last-in-First-out 效應，未發生碰撞或碰撞次數較少的工作站比較有機會搶到網路使用權。 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Ethernet 網路環境受限因素 CSMA/CD 網路的實際大小受限於各個網路元件的特性。這些特性包括：傳輸媒介(線路)長度及其傳遞延遲。集線器元件延遲(啟動，穩定，結束)。 MAUs及PHYs延遲(啟動，穩定，結束)。集線器所造成的訊框間隔萎縮。 DTEs執行CSMA/CD演算法的延遲。 MAUs及PHYs的衝撞偵測延遲。 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Fast Ethernet

Introduction The goal of the Fast Ethernet is to obtain an order of magnitude increase in speed over 10BaseT Ethernet (IEEE 802.3) while retaining the same wiring systems, MAC method, and frame formats. In IEEE 802.3, the longest distance between two stations is 2.5km, with a slot time of 51.2us (512 bits for 10Mbps). One way to increase the speed is to shorten the distance. In Hub architecture, the distance between station and Hub is at most 100m and the round-trip distance between two stations is 400m. A faster speed can be used to transmit frames under CSMA/CD protocol while keeping the minimum frame size as 512 bits. In the standard, the speed is 100Mbps and denoted as 100BaseT. (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Fast Ethernet Characteristics
100 Mbps IEEE CSMA/CD frame format Medium Twisted pair -- UTP, STP fiber CSMA/CD Protocol, do not support priority scheme Do not support guaranteed delay service Frames collision Bandwidth utilization is not guaranteed to be fair Low bandwidth utilization under heavy load Suitable for multimedia communications under moderate load Good fault tolerance Hub architecture 100Base4T Voice-grade Category 3 UTP. Use four pairs of twisted-pair wires. 100BaseX Category 5 UTP, STP, or Fiber optic. (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Communication Architecture
The Convergence Sublayer (CS) provides the interface between CSMA/CD MAC sublayer and PMD layer IEEE LLC IEEE 802.3 CSMA/CD MAC ANSI X3T9.5 MAC PHY PLS PMD CS MAU Coaxial Cable Fiber STP/UTP 實體層鏈結層

MII Interface Signaling
To support different transmission medium, a Media Independent Interface (MII) is defined between CS and PMD. The major functions of the CS Convert the transmit and receive serial data streams at the MAC sublayer interface into and from 4-bit nibbles for transfer across the MII. Relay the carrier sense and collision detection signals generated by the PMD sublayer to the MAC sublayer

MII Interface Signaling
Transmit clock(TxClk) Transmit data (TxD{0..3}) Transmit enable (TxEn) Carrier Sense (CRS) Collision detect (CD) Receive clock(RxClk) Receive data (RxD{0..3}) Receive data enable (RDv) Receive error (RErr) Transmit data Transmit enable Carrier Sense Collision detect Receive data Receive error MAC CS PMD CSMA/CD 次層界面 MII 界面 (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

100Base4T Category 3 UTP cable contains 4 separate twisted-pair wires.
To reduce the bit rate used in each wire, all four wire pairs are used in 100Base4T. For each direction of transmission, 3 pairs are used to transmit the frame and the other pair is used for carrier sensing and collision detecting (if any).

100Base4T 載波感測衝撞偵測第一對雙絞線載波感測衝撞偵測第二對雙絞線集線器工作站第三對雙絞線第四對雙絞線
工作站至集線器集線器至工作站

100Base4T -- Line Coding The bit rate on each pair of wires needs only be Mbps. The Manchester encoding used in Ethernet is not used due to a bit rate of Mbps requires a clock rate of MHz which exceeds the 30MHz limit set for use with such cables. To reduce the clock rate, a 3-level (ternary) code is used instead of straight (2-level) binary coding. 8B6T encoding: prior to transmission, each set of 8 binary bits is converted into 6 ternary (3-level) symbols. A symbol signaling rate of (100x6/8)/3 = 25 MHz.

100Base4T -- Line Coding The three signal levels used are +V, 0, -V (+,0,-). The codewords are selected such that the line is d.c. balanced (the line signal is zero). The 6 ternary symbols have 729 (36) possible codewords. To represent complete set of 8-bit byte combination, 256 codewords are needed. The selection rules are To achieve DC balance To ensure all codewords that have at least two signal transitions within them (for the purpose of synchronization) For the first case, only those codewords with a combined weight of 0 or +1 are selected. 267 codewords meet this condition. For the second case, those codewords with fewer than two transitions (5 codes) and those staring or ending with four consecutive zeros (6 codes) are eliminated. = 256.

8B6T Code Mapping Table 資料位元組字碼
0A A A A 0B B B B 0C C C C 0D D D D 0E E E E 0F F F F 1A A A A 1B B B B 1C C C C 1D D D D 1E E E E 1F F F F 資料位元組字碼 A C E A C E A C E A C E A C E A C E A C E A C E A C E A C E 8A AA CA EA 8B AB CB EB 8C AC CC EC 8D AD CD ED 8E AE CE EE 8F AF CF EF B D F B D F B D F B D F B D F B D F B D F B D F B D F B D F 9A BA DA FA 9B BB DB FB 9C BC DC FC 9D BD DD FD 9E BE DE FE 9F BF DF FF

8B6T Coding Scheme DC Balance: All the codewords selected have a combined weight of either 0 or +1. If a string of codewords each of weight +1 is transmitted, then the mean signal level at the receiver will move away rapidly from the zero level, causing the signal to be misinterpreted. This is known as DC Wander. To overcome this, whenever a string of codewords with a weight of +1 is to be sent, the symbols in alternate codewords are inverted prior to transmission. For example: => , , , ,... State Machine: 總和 = 0 總和 = 1 比重 = 1,字碼不變比重 = 1,字碼反相比重 = 0 字碼不變開始

8B6T Coding Scheme To reduce the latency during the decoding process, six ternary symbols corresponding to each encoded byte are transmitted on three wire pairs. ... A1(w=1) B1(w=1) C1(w=0) A2(w=1) B2(w=0) C2(w=0) A1(w=1) A2(w=1) B1(w=1) B2(w=0) C1(w=0) C2(w=0) IEEE 802.3 位元串 6 符號字碼傳送至三條雙絞線上雙絞線

8B6T Coding Scheme The transmission procedure adopted enables further error checking to be added to the basic CRC. At the end of each frame transmission (after the four CRC bytes have been transmitted) one of two different End-Of-Stream (EOS) codes is transmitted on each of the three pairs. 雙絞線 CRC-3 CRC-4 E E E E3 E2 總和 = 總和 = 1 E1 + - EOS 功能結束線路重新達成平衡

Collision Detection A DTE detects a collision by detecting a signal on pair 2 while it is transmitting. The hub detects a collision by the presence of a signal on pair 1. The strong signals transmitted on pairs 1, 3, and 4 from the DTE side each induce a signal into the collision detect wire (pair 2). This is known as Near-End CrossTalk (NEXT) which is interpreted by the DTE as a collision signal being received from the hub.

Collision Detection To minimize NEXT the preamble at the start of each frame is encoded as a string of 2-level (as opposed to 3-level) symbols. This increases the signal-level amplitude variations which helps the DTE/hub to distinguish between an induced NEXT signal and the preamble of a colliding frame. The preamble pattern: Start-of-Stream (SOS) is made up to two 2-level codewords, SOS-1 and SFD.

Gigabit Ethernet

Introduction Gigabit Ethernet is an extension to the 10 and 100 Mbps IEEE standards. Gigabit Ethernet is a connectionless protocol that each Ethernet frame contains a destination address, and is routed through the network. (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

GMII The GMII is divided into three sublayers: PCS (Physical Coding Sublayer) PMA (Physical Medium Attachment) PMD (Physical Medium Dependent) (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Gigabit Ethernet Network Structure
PCS PMA PMD Reconciliation Medium PLS MAC MAC Control (Option) LLC Higher Layers MDI AUI MII GMII 1Mbps, 10Mbps Mbps Mbps Mbps Physical Data Link Network Transport Session Presentation Application PHY MAU (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Gigabit Ethernet Repeater Set
MAC MAC Control (Option) LLC Higher Layers 1000 Mbps Link Segment Physical Data Link Network Transport Session Presentation Application PHY PCS PMA PMD Medium MDI GMII Reconciliation 1000 Mbps 基頻集線器 Link Segment 1000 Mbps 基頻集線器組 ISO 參考模式 CSMA/CD 網路

Frame Format (Carrier Extension)
Preamble SFD DA SA LEN LLC PAD FCS Extension , , <= N <= <= M <= 448 bytes 最短訊框尺寸（ >= 64 位元組）最短訊框尺寸 + 擴充尺寸（>= 512 位元組） FCS 錯誤檢查碼涵蓋範圍訊框之載波期間

Frame Bursting Example
訊爆週期時槽時間 (512 位元組）載波偵測延伸載波訊框間隔（96 位元時間）傳送訊框訊框 1 訊框 2 訊框 3 訊框 4 Preamble SFD DA SA LEN LLC PAD FCS

Gigabit Ethernet Communication Structure
1000BASE-LX nm 光傳送接收器 1000BASE-SX nm 1000BASE-CX STP 傳送接收器 1000BASE-T 4-Pair SMF MMF 50 um 62.5 um Balance Shielded Copper Cat-5 UTP 3 km m m m m m 8B/10B 編碼/解碼編碼/解碼 Gigabit Media Independent Interface (GMII) Media Access Control (MAC) Logical Link Control (LLC) Ethernet Upper Layers

Gigabit Ethernet Applications-- Multi-port Bridge (Single bandwidth)
衝撞網域 1 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 集線器 (Repeater) 多埠橋接器 (Multi-port Bridge) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 集線器 (Repeater) 集線器 (Repeater) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 衝撞網域 2 衝撞網域 3

Gigabit Ethernet Applications – Multi-port Bridge (Multiple Bandwidth)
10 Mbps 專屬線路 100 Mbps 專屬線路 1000 Mbps 專屬線路 1000 Mbps 專屬線路工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 1000 Mbps 10 Mbps 100 Mbps 1000 Mbps 多埠橋接器 (Multi-port Bridge) 1000Mbps 100 Mbps 集線器 (Repeater) 集線器 (Repeater) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 工作站 (DTE) 1000 Mbps 分享網路 100 Mbps 分享網路

8B/10B Encoding 8B/10B 編碼器 a b c d e i f g h j H G F E D C B A 10 8+Control GMII (125 Mbytes/s) 編碼器輸入編碼器輸出 PMA 服務界面 (125 M code_groups/s) PMD 服務界面 (1250 Mbps) 位元 0 先傳送 tx_code_group<9:0> 解碼器 x x x 解碼器輸入解碼器輸出位元 0 先接收 rx_code_group<9:0> Comma + Symbol 對齊 PCS 編碼功能 PCS 解碼功能 TXD<7:0> RXD<7:0> (C) All rights reserved by Assistant Professor Wen-Tsung Lin.

Ethernet 技術研討林文宗明新科技大學資訊工程學系助理教授工研院資通所無線通訊技術組顧問麟瑞科技股份有限公司技術顧問

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Presentation on theme: "Ethernet 技術研討林文宗明新科技大學資訊工程學系助理教授工研院資通所無線通訊技術組顧問麟瑞科技股份有限公司技術顧問"— Presentation transcript:

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Ethernet 技術研討 林文宗 明新科技大學資訊工程學系助理教授 工研院資通所無線通訊技術組顧問 麟瑞科技股份有限公司技術顧問

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Presentation on theme: "Ethernet 技術研討 林文宗 明新科技大學資訊工程學系助理教授 工研院資通所無線通訊技術組顧問 麟瑞科技股份有限公司技術顧問"— Presentation transcript:

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About project

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Ethernet 技術研討林文宗明新科技大學資訊工程學系助理教授工研院資通所無線通訊技術組顧問麟瑞科技股份有限公司技術顧問

Presentation on theme: "Ethernet 技術研討林文宗明新科技大學資訊工程學系助理教授工研院資通所無線通訊技術組顧問麟瑞科技股份有限公司技術顧問"— Presentation transcript: