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.
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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: nfhuang@cs.nthu.edu.tw).
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
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