1VLAN - FDDI-II HYBRID RING CONTROL All rights reserved. No part of this publication and file may be reproduced, stored in a retrieval system, or transmitted.

1VLAN -

FDDI-II HYBRID RING CONTROL

All rights reserved. No part of this publication and file may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior written permission of Professor Nen-Fu Huang (E-mail: [email protected]).

2VLAN -

FDDI-II Structure

StationManagement

SMT

CS-MUX

Circuit Switching Multiplexer(s)

LLC

I-MAC

Isochronous MAC

H-MUX Hybrid Multiplexer

PHY Physical Layer Protocol

SPM SONETPhysical Layer Mapping

FDDI-II通訊結構

HRC (Optional) Hybrid Ring Control

PMD Physical Layer, Medium Dependent PMD - Multi Mode Fiber, or SMF-PMD - Single Mode Fiber, or LCF-PMD - Low-cost Fiber, or TP-PMD - Twisted Pair Copper

or

鏈結層

實體層

SONET

STS-3c

傳輸媒介

MAC

HP-SAP (1)

I-SAP (16)

HI-SAP (16)

3VLAN -

FDDI-II Definitions

Basic Mode Support FDDI token ring operation only

Hybrid Mode Support variable rate packet switching service and time division

multiplexed (TDM) circuit switch service HI-SAP (Hybrid Isochronous-MAC Service Access Point)

Used by the I-MAC to access the WBCs. There are 16 HI-SAPs.

HP-SAP (Hybrid Packet-MAC Service Access Point) Used by the P-MAC to access the packet data channel. Only one HP-SAP exists (0.768 ~ 99.072 Mbps)

H-SAP (Hybrid Service Access Point) Service access points for the I-MUX

I-SAP (Isochronous-MAC Service Access Point) Service access points of the I-MAC (16 I-SAPs)

4VLAN -

FDDI-II Definitions

Cycle The HRC frame, 125 us, carries 3120 symbols at 100Mbps

Cycle Master The ring has only one Cycle Master at a time. Generating and maintaining the Cycle structure and the timing of the ring. Inserts a Latency Adjustment Buffer (LAB) to adjust the ring size to be an

integer multiple of 125 us. Selected by bidding among ranked Monitor Stations.

Cycle Sequence A scheme for indicating whether or not the correct order of cycle

transmission is being maintained during normal Hybrid Mode operation The sequence number of each cycle is indicated

5VLAN -

Isochronous Channels

125 us 125 us 125 us

125 us 125 us 125 us

A A A AB B B B

傳送方向

傳送端 接收端

.........

6VLAN -

Cycle Master

循環控制工作站 (Cycle Master)

Cycle 4(125 us)

Cycle 1

Cycle 2Cycle 3

循環標頭 (Cycle Header)

. . .

工作站

工作站

工作站

工作站工作站

7VLAN -

Cycle Structure

PA CHDPG 0

CG 0

CG 1

CG 7

CG 8

CG 48

CG 56

DPG 1

DPG 6

DPG 11

CG 95

CG 88... ... ... ......

125 us (3125 符號 )

16x8 位元組 16x8 位元組

CG 89

5 24

IMCP15P1P0 ...CSC1 C2SD

循環標頭 Cycle Header

SD = Starting Delimiter (symbols J & K)C1 = Synchronization Control (1 symbol). R & S are the permitted valuesC2 = Sequence Control (1 symbol). R & S are the permitted valuesCS = Cycle Sequence (2 symbols)P0-P15 = Programming Template (16 symbols)

R : Packet Data S : Isochronous Data T : Errored R or S

IMC = Isochronous Maintenance Channel (2 symbols)

DPG0-11 = Dedicated Packet Data Group (24 data symbols). Byte interleaved. (24x4 bits)/125 us = 0.768 MbpsCG0-95 = Cyclic Group 0 to 95 (32 symbols, 2 symbols per WBC)

8VLAN -

Cycle Sequence (CS)

Normally 64 ~ 255 Each Cycle has its CS value incremented

by one. 0 ~ 63 are reserved for Monitor

Contention process. Each potential Cycle Master (monitor) has

a ranking from 1 ~ 63. The value 0 indicates unranked monitors.

The monitor with the highest ranking will become the next Cycle Master.

9VLAN -

Cycle Header (12 位元組 )PreambleDPG0

DPG1

DPG2

DPG11

96rowsWBC

0WBC 1

WBC 2

WBC 3

WBC 4

WBC 5

WBC 6

WBC 7

WBC 8

WBC 9

WBC 10

WBC 11

WBC 12

WBC 13

WBC 14

WBC 15

...

傳送順序

0

8

16

88

125 us16 位元組

Cycle Transmission Order

10VLAN -

Bandwidth Allocation of a WideBand Channel (WBC)

1 8 2 16 4 32 8 64 (voice) 48 384 192 1536 193 1544 (T1) 240 1920 256 2048 (E1) 768 6144

位元 /125us 頻寬 (Kbps)

11VLAN -

Cycle Programming Templates

R R S S S R R S S R S S R R R R

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

R R R R R R R R R

2 3 4 7 8 101

1

IsochronousWBC

s Packet DataWBCs

(a) 可程式模板內容

(b) 廣頻通道分配情形

12VLAN -

Bandwidth Management

.. .

原始工作站

1

2

3

4

更改模板

(WBCk , Offsets)

Request

(WBCk , Offsets)

ACK

目的地工作站

通道分配 工作站

循環控制 工作站

工作站

13VLAN -

Cycle HeaderPreambleDPG0

DPG1

DPG2

DPG11

96rows

WBC 0

WBC 1

WBC 2

WBC 3

WBC 4

WBC 5

WBC 6

WBC 7

WBC 8

WBC 9

WBC 10

WBC 11

WBC 12

WBC 13

WBC 14

WBC 15

...

傳送順序

...

A

C

C

C

C

B0

8

80

88

5

13

93

D

S S SS R R R R R R R R R S RS

E

85

16 位元組

(125 us)

Bandwidth Allocation Example

14VLAN -

SDPA FC DA SA

資料 FCS ED FS

PACH

PACH

PACH

Cycle i

Cycle i+1

Cycle i+2

16 2 2 12 12 8944 8 1 3 符號

5 24 3096

5 24 3096

5 24 2808 288

9000 符號 = 3096+3096+2808

3096 3096 2808

Packets Transmission Example (Packet Size = 9000 Symbols, None of the WBCs is Allocated)

15VLAN -

Packet Transmission Example (Packet Size = 4500 Symbols, Half of the WBCs are Allocated)

SDPA FC DA SA 資料 FCS ED FS

Cycle i

Cycle i+1

Cycle i+2

16 2 2 12 12 4444 8 1 3 符號

5 24 1560 (=3096-1536)

5 24 1380 180

4500 符號 = 1560+1560+1380

PACH

5 24 1560 (=3096-1536)

1560 1560 1380

PACH

PACH

16VLAN -

SDPA FC ED

16 2 2 2 符號

PACH

循環

5 24

DPG0 1 2 3 4 5 6 7 8 9 10 DPG11

256

訊標

Token Transmission Example (Token Size = 24 Symbols, All the WBCs are Allocated)

17VLAN -

FDDI-II Operation

In general the hybrid ring is initialized in Basic Mode via the MAC Claim process.

The Monitor contention procedure selects the highest ranking Monitor station to become a Cycle Master.

The ring return to Basic Mode if any station is only capable of basic FDDI operation.

The Monitor Station may switch from basic to hybrid mode: No Basic Mode only station on the ring No other Cycle Master on the ring The Monitor station captures the token, or wins the Claim process

18VLAN -

FDDI-II Operation

The Monitor continue to transmit new cycle until the first transmitted cycle return if the ring is longer than 125 us.

Each returning cycle is kept in the LAB until the next cycle request signal is asserted.

The packet WBCs are delivered from LAB to the P-MAC as soon as possible to optimize the performance of the Timed Token Protocol.

To modify the PT, Cycle Master must capture the token from P-MAC.

SMT may take a station into Basic Mode by setting its class to Basic.

19VLAN -

FDDI-II Priority Levels

Once the WBCs' have been allocated, the isochronous traffic within them has the highest priority.

Second highest priority is the synchronous packet traffic to guaranteed with a delay not exceeding twice of TTRT value.

Third highest priority is given to asynchronous traffic operating in restricted token mode.

Lowest priority is given to asynchronous traffic that may be transmitted only by capturing a non-restricted token.

20VLAN -

Isochronous Channel Reservation

SMT P-MAC P-MAC SMT

通話起源工作站 通道分配工作站

通話申請

通話建立程序

CRQ

ICR

ICR

ICR

ICIICI

ICICPR

廣播

通話處理（通話拒絕）

應用層 網路層

ICR - 等時通道預約申請ICI - 等時通道預約通知

通道分配工作站保留等時通道並且記錄相關資訊

21VLAN -

Isochronous Call Establishment

應用層 SMT P-MAC P-MAC SMT

CRQ

CA

CRQCRQ

CA(CRF)

CA

CA

CRF

CRF

(CRF)

ICPICP

ICPICP

Steering Map to I-MAC

Steering Map to I-MAC

通話申請通知應用層接受申請 或拒絕申請

目的地工作站

通話申請

通話處理（通話拒絕） ICP - 等時通話參數

網路層 應用層網路層

通話起源工作站

22VLAN -

Isochronous Call Released From Destination

Steering Map to I-MAC

Steering Map to I-MAC

RLA

RLARLA

RLA

RLS

RLSRLS

RLSRLS

RLA

RLS

目的地工作站

應用層 SMT P-MAC P-MAC SMT網路層 應用層網路層

通話釋放通知

釋放等時通道

應用層釋放通話

通話釋放通知 RLS - 釋放RLA - 釋放回覆

通話起源工作站

23VLAN -

Isochronous Call Released From Source

Steering Map to I-MAC

Steering Map to I-MAC

通話釋放通知

RLARLA

RLA

RLA

RLSRLS

RLS

RLS

RLS

RLS

RLA

釋放等時通道

應用層釋放通話

目的地工作站

應用層 SMT P-MAC P-MAC SMT網路層 應用層網路層

通話釋放通知 RLS - 釋放RLA - 釋放回覆

通話起源工作站

24VLAN -

Isochronous Channel Release

SMT P-MAC P-MAC SMT

IRL

IRL

IRAIRA

IRA

廣播

IRL

通道分配工作站

開始釋放等時通道

網路層

通道分配工作站歸還等時通道

等時通道釋放回覆

IRL - 等時通道釋放 IRA - 等時通道釋放回覆

等時通道釋放確認

通話起源工作站