ethernet over sonet - krnet.or.kr · 예) ethernet 신호가 10mbps 신호 이므로 이를...

Intelligent Telecommunications Inc.

<1> KRnet 2003

Ethernet over SONET

2003.05. 24

김 호건

HW Development Team

㈜ 아이티

[email protected]

- EoS

- GFP

- VCAT

- LCAS


<2> KRnet 2003

Next Generation Network

IP

Service

CSU

DSU SDH

(STM) ATM

전용선서비스 (FE)

Telephone Line (ADSL/VDSL)

Metro Ethernet (FE)

Metro SWITCH

Metro SWITCH

GbE

L3 Switch

DSLAM

CSU

DSU

기존 데이터 통신 서비스

STM

DS1/3

IP

Service

NG-SDH

(STM)

ATM


Telephone Line (ADSL/VDSL)

Metro Ethernet (FE)

Metro SWITCH

Metro SWITCH

GbE

DSLAM

향후 데이터 통신 서비스

STM

FE

FE

GbE

DS1/3

STM

STM

GbE

CSU

DSU


DS1/3


<3> KRnet 2003

기존 TLS #1 (Transparent LAN Service)

라우터

CSU

STS-m

STM-n

STS-m

STM-n SONET / SDH

Network

INTERNET

DS-1

DS-1

V.35 (Nx64)

FE

FE

V.35 (Nx64)


<4> KRnet 2003

기존 TLS #2 (Transparent LAN Service)

라우터

OCSU (단독형)

STS-m

STM-n

STS-m

STM-n

SONET / SDH

Network

INTERNET

FE

OCSU (집합형)

V.35 (Nx64)

DS-1

DS-1

Optic V.35 (Nx64)

FE


<5> KRnet 2003

EoS의 배경

EoS NG-SDH for MSPP

TDM (DS-1/3, STM-1/4/16) 신호와 데이터 (Ethernet, IP) 서비스 통합 시스템

기존 SDH 전송망 인프라를 그대로 이용하여 VCAT 서비스 가능

Ethernet over SDH (EoS)에 의한 QoS 보장형 고품위 인터넷 접속 서비스 제공 가능

L2/L3/L4 Switch & Router 기능 내장

기존 SDH 망과 연동 유지

기존의 TLS를 이용한 Ethernet service를 수용하기 위해서 발생되는 문제

속도 제한 (Max 64x31 = 1984Kbps)

유지보수의 어려움

PDH 신호를 이용

POS 등 다양한 방식의 Ethernet 접속 방식이 있지만 표준화 되지 않음.

저가격의 Metro Ethernet 장비 출현

End to end : LAN

문제점 : TLS와 동일한 QoS 보장을 못함.

ITU에서 국제 표준으로 Ethernet을 수용하기 위한 기술 규격화

GFP, VCAT, LCAS

기존의 동기식 전송망을 통하여 Ethernet service 가 가능

효율적인 Bandwidth 할당

기존에 PDH 망에 수용되는 Ethernet 신호를 SDH 망에서 수용

Requirement of NG-SDH

EoS 를 기반으로 하는 망을 구축하기 위해서는 SDH 망이 Full SDH 망으로 구성되어야 한다.


<6> KRnet 2003

EoS 장비의 인터페이스

PABX

Telephone Line

House

Telephone Line

DSLAM

HUB

SWITCH

STM-1

DS-3 DS-1

Ethernet

Ethernet

GSR GbE

현재의 SDH 기간망 (10G, BDCS, DWDM)

EoS

SDH

데이터 통신망 (GbE, 10GbE)

GbE

FE


<7> KRnet 2003

EoS 에서 필요한 기술

개념

기존의 SDH는 DS-1/-3, STM-1/-4/-16/-64 신호등을 접속하여 STM 신호로

다중화하여 전송하는 것임.

이 접속에 Fast Ethernet과 GigaBit Ethernet등의 접속을 추가하기 위한 것임.

이 Ethernet 접속을 SDH 규격에 추가하기 위한 ITU 활동

G.707의 HO/LO Virtual Concatenation(VCAT) 의 기능 추가

G.7041에서 Ethernet 신호를 GFP 프레임화하는 표준화

G.7042에서 VCAT을 위한 프로토콜(시그널링)로 LCAS를 표준화

VCAT/LCAS/GFP의 기능

예) Ethernet 신호가 10Mbps 신호 이므로 이를 기존의 방식으로는

VC3(51M 급) 신호에 mapping 하므로 40M 정도의 대역폭을 버리게 된다.

따라서, 효율적으로 대역폭을 사용하기 위하여 VC12 x 5 (2.176M x 5 =

10.88M)를 mapping 하는 방식이 VCAT이다. VC12 신호 5개가 하나의

VCAT 신호임을 나타내 주는 것이 LCAS 라는 기술이고, Ethernet 신호를

VC12 신호에 mapping 하기 위한 frame을 GFP 라는 것이다.


<8> KRnet 2003

EoS 에서 필요한 기술

GFP (Generic Framing Procedure)

Ethernet 신호를 패킷 형태의 프레임으로 변경하는 것으로 기존의 ATM에서 사용하던 HEC를 사용하여 프레임 헤더를 생성하여 프레임화 한다.

프레임 경계 식별을 위하여 ATM의 HEC를 사용한다.

에러 콜렉션을 위하여 CRC를 사용한다.

참조 : G.7041

VCAT (Virtual Concatenation)

HO VCAT : VC3/4 신호 여러 개를 다중화하는 것, LCAS는 MSOH의 H4 바이트를 이용하여 LCAS를 사용한다.

LO VCAT : VC11/VC12 신호를 여러 개 다중화하는 것으로, LCAS는 K4의 비트1,2 를 사용한다.

VC Concatenation 되어 있는 VC 신호들을 VC Group(VCG) 이라 한다.

참조 : G.707의 11.1항

LCAS (Link Capacity Adjustment Scheme)

In Higher Order VC

Use H4 byte in POH

X * 49.536Mb/s (STS-1 payload rate) (X = 256, 12.386Gb/s)

X * 149.760Mb/s (STS-1 payload rate) (X = 256, 38.338Gb/s)

In Lower Order VC

Use Bit 1,2 in K4 byte (Z7 in SONET)

X * 1.600Mb/s (VC-11 payload rate) (X = 64, 102.400Mb/s) (X = 28, 44.800Mb/s)

X * 2.176Mb/s (VC-12 payload rate) (X = 63, 137.088 Mb/s) (X = 21,45.696Mb/s)

참조 : G.7042


<9> KRnet 2003

EoS 기술의 적용

Mapping of the Ethernet traffic into the SDH Pipe (Path)

X.86: Ethernet over LAPS

G.7041: Generic Framing Procedures (GFP: G.7041)

Virtual Concatenation (VCAT)

Specified in G.707 (Network Node Interface for the SDH)

G.7042: Link Capacity Adjustment Scheme (LCAS)

Shared

TDM Bus

Ethernet

PHY

Ethernet

MAC

EoS

Framer

(GFP/X.86)

T1/E1

PHY

VCAT

Controller

LCAS

Controller

SDH

Mapper

TDM

Switch

STM-N

Framer

WAN

LAN

TDM

•Rate limiting


<10> KRnet 2003

Packet adapt in TDM signal 1

Traffic

Time

Packet(Burst)

Traffic

Time

TDM(Continuous)

Lost Lost

Lost


<11> KRnet 2003

Packet adapt in TDM signal 2

Traffic

Time

Packet(Burst)

Traffic

Time

Queue

QoS

Classification

Marking

Ethernet Packet

Priority Queue

Packet Drop

Scheduling

Shaping

Traffic

Time

TDM(Continuous BW)

SDH


<12> KRnet 2003

EoS 구성 요소

GFP/VCAT/LCAS

GFP Insert

STM-N

Ethernet Packet

VCAT #1

GFP Delete

Ethernet Packet

VCAT #2

LCAS (VCAT member add and delete)

LCAS Processor

LCAS Processor

Insert Idle frame

Delete Idle frame Insert

GFP field


<13> KRnet 2003

GFP : Adaptation mode

Adaptation mode

Frame-Mapped adaptation mode : GFP-F

Type of GFP payload dependent mapping in which the client signal frame is

mapped in its entirety into one GFP frame

PDU oriented : 10Base, 100Base, 1G Ethernet, 10G Ethernet

Transparent adaptation mode : GFP-T

Type of GFP payload dependent mapping in which block-coded client characters

are decoded and then mapped into a fixed-length GFP frame and may be

transmitted immediately without waiting for the reception of an entire client data

frame

Block-code oriented : ESCON, Fibre channel, FICON, GigE


<14> KRnet 2003

GFP : Frame and Fields

Core Header

Payload Area

4

4 - 65535

1 2 3 4 5 6 . . . n

Octet Transmission

Order

Octet Bit

Bit Transmission

Order

Frame Size and transmission order Fields Constituting a GFP client frame

16bit payload Length indicator

cHEC (CRC-16)

Payload Header

(4-64 Bytes)

Client Payload

Information Field

(0 to 65535-X bytes)

Optional Payload FCS

(4 byte, CRC-32)

2 byte

2 byte


<15> KRnet 2003

GFP : Core + Payload Header

Core Header + Payload Area (Variable-length)

Core Header = PLI + cHEC

Payload Area = Payload Header + Payload + FCS(option)

PLI

(2) Payload Information field

PTI PFI EXI UPI

Linear frame에서만 적용

1 5 65535

3b 1b 4b 8b

cHEC

(2)

Payload

Header

(4~64)

Payload

FCS

(optional)

(4)

CID Spare

Type

(2)

Extension Header

(0 ~ 58)

tHEC

(2)

eHEC

(2)

Core

Header Payload Area

8b 8b

PLI : PDU Length Indicator

cHEC : Core HEC

HEC : Header Error Check

PTI : Payload Type Identifier

PFI : Payload FCS Indicator

EXI : Extension Header Identifier

UPI : User Payload Identifier

tHEC : Type HEC

eHEC : Extension HEC

CID : Channel ID

DP : Destination Port

SP : Source Port

DE : Discard Eligibility

CoS : Class of Service

TTL : Time to Live


<16> KRnet 2003

GFP : Core Header

Allows GFP frame delineation independent of the content of the higher layer PDUs.

Scrambling

XORing with the fixed pattern 0xB6AB31E0 for DC-balanced

0xB6AB31E0

= “1011_0110_1010_1011_0011_0001_1110_0000”

Barker-like sequence (modulo 2 addition of 0xB6AB31E0 with header

PLI + cHEC

PLI(PDU Length Indicator)

Binary number representing the number of octets in the GFP Payload Area.

16 bits => 216 = 65,536

Absolute minimum value : 4 octets

Value 0~3 : Reserved for GFP control frame

cHEC(Core HEC)

G(x) = x16 + x12 + x5 + 1

Single error correction & multi-bit error detection

multi-bits errored GFP frame shall be discarded

Provide relevant system records for performance monitoring purposes

PLI <15:08> 1

PLI <07:00>

cHEC <15:08>

cHEC <07:00>

2

3

4


<17> KRnet 2003

GFP : Payload Header

GFP Payload Area Variable length : from 4 to 65 535 octets

An implementation should support reception of GFP frames with GFP Payload Areas of at least 1600 octets

4 bytes Optional FCS

Payload Header

Variable length : from 4 to 64 octets

intended to support data link management procedures specific to the higher-layer client signal

Type : distinguishes between services in a multi-service environment

PTI : 3-bit Payload Type Identifier

– “000” => for GFP user frames conveying client data.

– “100” => for GFP user frames conveying Client Management

PFI : 1-bit Payload FCS Indicator

– “1” => indicates the presence of a Payload FCS.

– “0” => indicates the absence of a Payload FCS

EXI : 4-bit Extension Header Identifier : Network Topology Information for Connection

– “0000” => Null Extension Header

– “0001” => Linear Frame

– “0010” => Ring Frame

UPI : 8-bit User Payload Identifier : Specifies the type of client frame contained within the payload area

– Client data frames : Transport Data from the Client Signal

– Client management frames : Transport Information Relevant to Managing the Client Connection


<18> KRnet 2003

GFP : Frames

Client Data Frames

Client data is transported over GFP using client data frame

PTI = 000

PFI/EXI/UPI = payload specific, UPI = see next slide

Client Management Frames

Provide generic mechanism to send optionally Client Management frames

PTI = 100

PFI/EXI/UPI = payload specific , UPI = see next slide

GFP control frame

Used in the management of GFP connection

Only GFP idle frame is defined

Special 4-octet frame with CoreHeader = 0x0000 & PLI = 0. No payload area

Final value after core header scrambling is 0xB6AB31E0

Intended for use as a filler frame

PLI =1,2,3 : further study


<19> KRnet 2003

GFP : Extension Headers

GFP Extension Headers

0-to-60 octet extended field that supports technology specific data link headers such as virtual link identifiers, source/destination addresses, port numbers, Class of Service, extended header error control, etc.

Null Extension Header

Extension header for linear

Channel ID (CID) field : to indicate 256 communication channels at GFP termination point.

Type <15:08> 5

Octet Transmission

Order

Octet

Bit Bit Transmission

Order

Type <07:00>

tHEC <15:08>

tHEC <07:00>

6

7

8

CID <07:00> 9

Octet Transmission

Order

Octet

Bit Bit Transmission

Order

Spare <07:00>

eHEC <15:08>

eHEC <07:00>

10

11

12

Type <15:08> 5

Type <07:00>

tHEC <15:08>

tHEC <07:00>

6

7

8 Null Extension Header

Extension header for linear

CRC-16

CID Spare

8b 8b

eHEC

16b

tHEC

16b

Type

16b

tHEC Type Null

Linear


<20> KRnet 2003

GFP : Idle Frames

GFP Idle frames

special four-octet GFP control frame consisting of only a GFP Core Header

with the PLI and cHEC fields set to 0, and no Payload Area

is intended for use as a filler frame for the GFP transmitter

Octets

1

2

3

4

Bits

1 2 3 4 5 6 7 8

00 (B6) hex

00 (AB) hex

00 (31) hex

00 (E0) hex

Octet Transmission

Order

Bit Transmission Order


<21> KRnet 2003

GFP : Payload Information field

Contains the framed PDU for frame mapped PDU or, in case of

transparent GFP, a group of client signal characters.

This variable length field may include from 0 to 65,536 – X octets, where X is

the size of the payload header

pFCS(payload Frame Check Sequence) : option

Protects the contents of the GFP Payload Information field

CRC-32

G(x) = x32 + x26 + x26 + x23 + x22 +x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1

Generation step : see recommendation

– GFP payload information field = M(x) of degree k

– U(x) = all-one polynomial of degree 32

– 1’s complement of Remainder R(x) = (M(x) x32 + U(x) xk) / G(x)

Detection step

– Same as generation step

– In the absence of errors, the remainder shall be 0xC704DD7B


<22> KRnet 2003

GFP : Payload scrambling

Frame multiplexing

multiplexed on a frame-by-frame basis

When there are no other GFP frames available for transmission, GFP Idle frames shall be inserted

Payload Scrambling

x43 + 1, SSS(Self Synchronous Scrambler)

Provide security against payload information

At the source, scrambling is enabled starting at the first transmitted octet after the cHEC, and is disabled after the last transmitted octet of GFP frame.When the scrambler/descrambler is disabled, its state is retained.

At sink, the process depends on the state of cHEC check algorithm

A) in the HUNT/PRESYNC state, the descrambler is disabled

B) in the SYNC state, descrambler is enabled only for the octets between the cHEC field and the end of the candidate GFP frame

“x43

+1“ Scrambler

D1 D43 D2

X(t) Y(t)

Y(t - 43)

“x43

+1“ De-scrambler

D43 D1 D2

Y(t) X(t)

Y(t - 43)


<23> KRnet 2003

GFP : Frame MUX, Scheduling

Frame multiplex (including scheduling algorithm)

Frame delineation

CSF(Client Signal Fail) indication

Defect handling Core Header

Scrambler

Frame Multiplex

Payload

Scrambler

Payload

Mapping

/

Demapping

Payload

Descrambler

Core Header

Checker

Client Management

IDLE insert

Octet streams from

Client-specific

Source adaptation

processes

Client Management

IDLE termination

Octet streams to

Client-specific

Sink adaptation

processes

Frame Demultiplex


<24> KRnet 2003

GFP : Frame Delineation State Diagram

Used a modified version of the HEC check algorithm specified in ITU-T

I.432(ATM)

HUNT SYNC Incorrect cHEC

Correct cHEC

Incorrect cHEC

Error correction disabled

Pre_SYNC

Pre_SYNC

Virtual

Framer

(up to M)

Pre_SYNC

Pre_SYNC

Correct cHEC

DELTA consecutive Correct cHECs

DELTA = 1

Error correction disabled

Octet-by-octet

Frame-by-frame

Error correction enabled Frame-by-frame


<25> KRnet 2003

GFP : Defect handling

CSF : failure client signal

Ingress : communicated to far-end by a CSF client management frame

Egress : client-specific mapping defects such as payload errors

Loss of client signal (UPI = “0000 0001”)

Loss of client character synchronization (UPI = “0000 0010”)

SSF : GFP Loss or propagation of TSF events

TSF : failure events detected in the SONET/OTN

CSF : Client Signal Fail SSF : Server Signal Fail TSF : Trail Signal Fail

Ingress Client Process

GFP Client-specific

Source Adaptation Process

GFP Common Process(TX)

Transport Network

Egress Client Process

GFP Client-specific

Source Adaptation Process

GFP Common Process(RX)

Transport Network

CSF

SSF

TSF


<26> KRnet 2003

GFP-F : Ethernet MAC payload

Ethernet MAC encapsulation

one-to-one mapping between a higher-layer PDU and a GFP PDU

Ethernet Inter-Packet Gap (IPG) deletion and restoring

Preamble Start of Frame Delimiter

Destination Address

Source Address

Length/Type

MAC client Data

Pad

FCS

Ethernet MAC Frame

Payload FCS (optional)

PLI cHEC Type tHEC

Extension Header

Payload

Information

Field

GFP Frame

Core Header

Payload Header


<27> KRnet 2003

GFP-T : Introduction

Transparent mapping

8B10B clients => 64/65B

Services (SAN)

Fiber channel

ESCON

FICON

Full-duplex Gigabit Ethernet

* ESCON : Enterprise Systems CONnection

* FICON : Fiber CONnection

Payload

N (8 65B + 16)

Payload FCS (optional)

PLI cHEC Type tHEC

Extension Header

Payload

Information

Field

GFP Frame

Payload

N (8 65B + 16)

Payload

N (8 65B + 16)


<28> KRnet 2003

GFP-T : Transparent mapping of 8B/10B clients

require very low transmission latency

Ex. Fibre Channel, ESCON, FICON, and Gigabit Ethernet

Rather than buffering an entire frame of the client data into its own GFP frame,

the individual characters of the client signal are demapped from the client

block codes and then mapped into periodic, fixed-length GFP frames

Core

Payload

Payload Header

Payload

N (8 65B + 16)

Optional(CRC-32)

PT MSB

PT LSB

tHEC MSB

tHEC LSB

FCS[31:24]

FCS[23:16]

FCS[15:8]

FCS[7:0]

Length MSB

Length LSB

cHEC MSB

cHEC LSB


<29> KRnet 2003


Capacity

Client un-encoded

data rate

VC Path Size

Min. number of 65B blocks/GFP frame

160 Mbit/s STS-1-4v / VC-3-4v 1

425 Mbit/s STS-3c-3v / VC-4-3v 13

850 Mbit/s STS-3c-6v / VC-4-6v 13

1000 Mbit/s STS-3c-7v / VC-4-7v 95

NOTES

Note 1:The minimum number of superblocks shown here assumes a Null Extension Header and no optional payload FCS.

Note 2: The larger the number of superblocks used per GFP frame, up to the payload size limit, the more bandwidth is

available for OAM communications.


<30> KRnet 2003



<31> KRnet 2003

GFP Frame : GFP-F/GFP-T

PLI 2byte

Cilent PDU 0~65,531 byte

cHEC 2byte

Payload Header 4byte

FCS(Option) 4byte

GFP-F frame

GFP Header GFP Payload GFP FCS

PLI 2byte

8 x 64B/65B + 16 Superblock bits

cHEC 2byte

Payload Header 4byte

FCS(Option) 4byte

#1 #2 #N-1 #N

GFP-T frame

64B/65B super-block

(Flag bits carried in Last octet of the

Super-block)

64/65B #1

64/65B #2

64/65B #N-1

64/65B #N

F1 | F2 | … | F8

CRC-16 MSB

CRC-16 LSB

1 | CCL#1 | CCI#1

DCI#8-n

DCI#1

1 | CCL#n | CCI#n 64B/65B block

(minus Flag bits)


<32> KRnet 2003

Frame-based GFP vs. Transparent GFP

Frame-Mapped GFP Transparent-Mapped GFP

Variable Length GFP Frames Fixed Length GFP Frames

1-to-1 mapping of Data Packets to GFPFrames

N-to-1 mapping of client “characters” to GFPFrames

Point-to-Point, Packet Aggregation, orResilient Packet Ring Network Topology

Primarily Point-to-Point Topology using VirtualConcatenation

Requires “MAC” to terminate client signal andpass only data packets.

Only 8B/10B PHY layer terminated; “MAC”not required to terminate higher layer protocol.

Data only passed in 8B format. Data and control compressed using 64B/65Bre-coding.

Channel-associated control possible usingGFP Control Frames.

Channel-associated control possible usingGFP Control Frames.

Unclear if/how client LOS, Loss-of-Sync, orcode violations should be communicated tofar-end.

Transparent mapping defines mechanisms forcommunicating LOS, Loss-of-Sync, codeviolations to far end.

Doesn‟t define client egress action due toSONET/SDH signal failure.

Defines client egress action due toSONET/SDH signal failure.


<33> KRnet 2003

SDH : Mapping

C-11 VC-11 TU-11

TU-12 C-12 VC-12

TU-2 C-2 VC-2 TUG-2

Mapping Aligning Multiplexing

C-3

VC-3

VC-3 TU-3 TUG-3

C-4 VC-4

AU-3

AU-4

STM-0

AUG-1 STM-1

C-4-4c VC-4-4c

C-4-16c

AU-4-4c

AU-4-4c VC-4-4c

C-4-64c VC-4-4c

C-4-256c

AU-4-4c

AU-4-4c VC-4-4c

AUG-4

AUG-16

AUG-64

AUG-256

STM-4

STM-16

STM-64

STM-256

1

3

4

1

7

7

3

1

1

1

1

1

4

4

4

4

Pointer processing

3


<34> KRnet 2003

VCAT : Introduction

New application over SONET

Transparent LAN Service(10Mbit/s, 100Mbit/s, 1Gbit/s)

High speed Internet

IP VPN

Video Distribution

Virtual Concatenation

Use higher efficiencies of SPE, Virtual concatenation for increased bandwidth efficiency

Provide multiple sized (Dynamic Allocation) channels over SONET

Transparent to intermediate SONET on the path between ends of a channel

Satisfy new applications

SPE

VT-2

VT-1.5

STS-1

STS-3c

STS-12c

STS-48c

Payload Capacity

2.176 Mbit/s

1.600 Mbit/s

49.536 Mbit/s

149.760 Mbit/s

599.040 Mbit/s

2.396160 Gbit/s

SONET

Service/Bit Rate Without Contiguous Virtual

Ethernet/10 Mbit/s STS-1 20% VT-1.5-7v 89%

ATM/25Mbit/s STS-1 50% VT-1.5-16v 98%

Fast Ethernet/100Mbit/s none STS-3c 67% VT-1.5-63v 99% STS-1-2v 100%

ESCON/200Mbit/s none STS-12c 33% STS-1-4v 100%

Gigabit Ethernet/1Gbit/s none STS-48c 42% STS-3c-7v 95%


<35> KRnet 2003

VCAT : Introduction

Definition

“ A procedure whereby a multiplicity of virtual containers is associated one with another with the result that their combined capacity can be used as a single container across which bit sequence integrity is maintained ”

Contiguous concatenation (VC-Xc)

Uses a concatenation indicator in the pointer (H1, H2).

Multiple SDH payload containers are transported as a single module.(VC-4-4c, VC-4-16c)

Waste of bandwidth resulting from large jumps

Legacy SDH equipment may not support contiguous concatenation transport switching.

Virtual concatenation (VC-Xv)

The member of the VCG(virtual concatenation group) are routed and transported individually.

Requires concatenation functionality only at the source and destination SDH NE ends.

In Higher order VC

Use H4 byte in POH

X * 49.536Mb/s (STS-1 payload rate)

In Low order VC

Use Bit 2 in K4 byte (Z7 in SONET)

X * 1.600kb/s (VC-11 payload rate)

X * 2.176kb/s (VC-12 payload rate)


<36> KRnet 2003

VCAT : Introduction

Concatenation :

Provide concatenated bandwidth of X times Container-N

Contiguous Concatenation : VC-Xc

Maintains the contiguous bandwidth throughout the whole transport

Virtual Concatenation : VC-Xv

breaks the contiguous bandwidth into individual VC(Virtual Container)s

transport the individual VCs

realign these VCs to a contiguous bandwidth

Differential delay

Possible to perform conversion between the two type of concatenation

Why virtual concatenation ?

Provide flexible bandwidth => increase bandwidth efficiency


<37> KRnet 2003

VCAT : GbE

Link

Layer

IP

Layer

SDH/SONET Network

VC-4-16c/STS-48c pipe

(40% efficiency) 1 Gb/s Traffic Point-to-point I/F

1 Gb/s

Ethernet

Link

Layer

IP

Layer

SDH/SONET Network

Single

Point-to-point I/F

1 Gb/s

Ethernet

VC-4-7v/STS-3c-7v

(95% efficiency) 7 independently routed

STM-1/OC-3 pipes

1 Gb/s

Ethernet

1 Gb/s

Ethernet


<38> KRnet 2003

VCAT : HO VC, structure

X VC-3/4s(VC-3/4-Xv, X=1 … 256)

Payload Capacity : X * 48.384/149.760kbit/s (X = 1 ~ 256)

VC-3-Xv/STS-1-Xv Structure VC-4-Xv/STS-3c-Xv Structure

J1

B3

C2

G1

F2

H4

F3

K3

N1

J1

B3

C2

G1

F2

H4

F3

K3

N1

1

9

1 XX x 84

1

9

1

1 30 59fixed stuff

125ms

125ms

125ms

VC

-3-X

v/

ST

S-1

-Xv S

PE

VC-3-Xv/STS-1-Xv SPE

payload capacity

J1

B3

C2

G1

F2

H4

F3

K3

N1

J1

B3

C2

G1

F2

H4

F3

K3

N1

1

9

1 XX x 260

1

9

1

1

125ms

125ms

125ms

VC

-4-X

v/

ST

S-3

c-X

v S

PE

VC-3-Xv/STS-1-Xv SPE

payload capacity

87 261

VC-3/STS-1 #X

VC-3/STS-1 #1 VC-4/STS-3c #1

VC-4/STS-3c #X


<39> KRnet 2003

VCAT : HO VC, H4 OH coding

J1

B3

C2

G1

F2

H4

F3

K3

N1

H4 Byte

b1 b2 b3 b4 b5 b6 b7 b8

1st multiframe indicator MFI1 (b1- b4)

1st MF

no. 2

nd MF

no.

Sequence Indicator MSBs (b1- b4) 1 1 1 0 14 n –1

Sequence Indicator LSBs (b5 – b8) 1 1 1 1 15 n – 1

2nd

multiframe indicator MFI2 MSBs (b1 – b4)

0 0 0 0 0 n

2nd


0 0 0 1 1 n

Reserved („0000‟) 0 0 1 0 2 n

Reserved („0000‟) 0 0 1 1 3 n

Reserved („0000‟) 0 1 0 0 4 n

Reserved („0000‟) 0 1 0 1 5 n

Reserved („0000‟) 0 1 1 0 6 n

Reserved („0000‟) 0 1 1 1 7 n

Reserved („0000‟) 1 0 0 0 8 n

Reserved („0000‟) 1 0 0 1 9 n

Reserved („0000‟) 1 0 1 0 10 n

Reserved („0000‟) 1 0 1 1 11 n

Reserved („0000‟) 1 1 0 0 12 n

Reserved („0000‟) 1 1 0 1 13 n

Sequence Indicator MSBs (b1- b4) 1 1 1 0 14 n

Sequence Indicator LSBs (b5 – b8) 1 1 1 1 15 n

2nd


0 0 0 0 0 n + 1

2nd


0 0 0 1 1 n + 1

Reserved („0000‟) 0 0 1 0 2 n + 1

One of the VC-3/VC-4 within the

VC-3-Xv/VC-4-Xv group

VC-n-Xv sequence and multi-frame indicator H4 coding


<40> KRnet 2003

VCAT : HO VC, H4 OH

VC-3/4-Xv sequence and multiframe indicator H4 coding

H4 : use Bit 7, 8 as a multiframe indicator for VC-2/1 payload

H4 : use Bit 5,6,7,8 as HO VCAT multiframe indicator

Two stage 512msec : 4096 frame

Sequence indicator : SQ MSB + SQ LSB


<41> KRnet 2003

VCAT : LO VC, Capacity of VC-1n-Xv

Capacity of Virtually Concatenated VC-1n-Xv


<42> KRnet 2003

VCAT : LO VC, structure

VC-11-Xv, VC-12-Xv, VC-2-Xv (X = 1 ~ 256)

VC-1n-Xv structure

VC-11-Xv/VT1.5-Xv Structure VC-12-Xv/VT2-Xv Structure

V5

J2

N2

K4

1

4

1 XX x 25

1

500ms

500ms

VC

-11-X

v/

VT

1.5

-Xv S

PE

VC-11-Xv/VT1.5-Xv SPE

payload capacity

VC-11/VT1.5 #1

4

V5

J2

N2

K4

1

1

26

500ms

VC-11/VT1.5 #X

V5

J2

N2

K4

1

4

1 XX x 34

1

500ms

500ms

VC

-12-X

v/

VT

2-X

v S

PE

VC-12-Xv/VT2-Xv SPE

payload capacity

VC-12/VT2 #1

4

V5

J2

N2

K4

1

1

35

500ms

VC-12/VT2 #X


<43> KRnet 2003

VCAT : LO VC, K4 bit 1,2

V5 POH Signal Label

b5, b6, b7 : “101” : Extended signal label

Dynamic allocation VC11/VC12 signals to Ethernet port

Considering 63 x VC of max size for VCG

Control VCG using LCAS (K4 bit 1,2)

RX VCG need alignment buffer for various delay compensation of VCs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

0 1 1 1 1 1 1 1 1 1 0 Extended Signal Label 0 R R R R R R R R R R R R

K4 bit1

Bit 2 string in K4 byte

1 2 3 4 5 6 7 8 9 1

0

1

1

1

2

1

3

1

4

1

5

1

6

1

7

1

8

1

9

2

0

2

1

2

2

2

3

2

4

2

5

2

6

2

7

2

8

2

9

3

0

3

1

3

2

Frame count Sequence

Indicator CTRL

G

I

D

Spare

R

S

-

A

C

K

Member status CRC-3

K4 bit2

Multiframe alignment bits


<44> KRnet 2003

VCAT : LO VC, Extended signal label

K4 Bit 1 : Extended signal Label

프레임 바이트를 구성

V5의 Signal Label이 Bit 5,6,7 “101”일 경우 K4 bit 1으로 Signal Label을 확장

32bit로 구성 : 1 bit (500usec) 32bit (16msec)

K4 Bit 2 : Lower Order Virtual Concatenation

Member Status

동일 VCG의 member에 대한 상태로 source와 sink 사이에 이용

63개의 member 상태는 16msec x 8 frame이면 모든 상태를 알 수 있음


<45> KRnet 2003

VCAT : LO VC, K4 bit 2

Frame Count : 25 = 32 프레임을 카운트 K4 bit 1으로 32 멀티 프레임을 하나의 프레임으로 구분 : 500usec x 32 = 16msec

총 시간 : 16msec x 32(frame count) = 512msec

125usec frame 수 : 4 frame x 32 (multi-frame) x 32 (frame count) = 4096 frame

Member status를 알기 위해서는 : 16msec x 8(frame count) = 128msec

하나의 멀티 프레임에서 4번의 member status를 확인

Bit 2 string in K4 byte

1 2 3 4 5 6 7 8 9 1

0

1

1

1

2

1

3

1

4

1

5

1

6

1

7

1

8

1

9

2

0

2

1

2

2

2

3

2

4

2

5

2

6

2

7

2

8

2

9

3

0

3

1

3

2

Frame count Sequence Indicator CTRL

G

I

D

Spare

R

S

-

A

C

K

Member status CRC-3


<46> KRnet 2003

VCAT : LOVC

Frame Count : MFI : Multi-frame counter

Sequence Indicator : 동일한 VCG의 각 member

6비트 : 63개의 member(0~62, 63번은 NA)를 구성, VC 그룹을 0~63으로 구분

At initiation of a VCG source all member SQ shall be set to the highest possible value.

Control

At initiation of a VCG source all members shall send CTRL=IDLE.

0001 ADD This member is about to be added to the group

0010 NORM Normal transmission

0011 EOS End of Sequence indication and Normal transmission

0101 IDLE This member is not part of the group or about to be removed

1111 DNU Do Not Use (the payload) the Sk side reported FAIL status

0000 FIXED This is an indication that this end uses fixed bandwidth (non-

LCAS mode)

Value

Msb Lsb

Command Remarks

Control 내용


<47> KRnet 2003

VCAT : K4 Frame 및 Frame count, SQ(MFI)

0,8,16,24 frame count 번호에서 0 ~ 7번째의 member status를 표시함

512msec동안에 Member 당 1 비트가 4번 반복됨

“0” 정상, “1” fail

01111111110 0

Frame count

0

SQ

01111111110 1

Frame count

0

SQ

01111111110 31

Frame count

0

SQ

01111111110 0

Frame count

1

SQ

01111111110 1

Frame count

1

SQ

01111111110 31

Frame count

1

SQ

01111111110 0

Frame count

62

SQ

01111111110 1

Frame count

62

SQ

01111111110 31

Frame count

62

SQ

16msec

512msec

VC #1

VC #2

VC #63

128msec(member status를 알 수 있는)


<48> KRnet 2003

VCAT : LOVC

GID (Group IDentification bit)

동일한 VCG에서 모든 member(0~62)의 GID bit는 동일한 frame count에서

동일한 값을 갖는다.

Pseudo-random pattern 215-1 사용

RS-ACK

NMS에서 LCAS를 통하여 add/delete member 수행시 필요

CRC-3

FCS


<49> KRnet 2003

VCAT : Differential Delay

수신단에서 하나의 VCG를 구성하는 VC 들 간에 재 정렬을 위한 버퍼가 필요(가장 늦게 도착하는 VC를 기준으로 이전에 도착하는 VC들에 대한 incoming

buffer가 필요) Differential Delay

VCG를 구성하기 위해 하나의 GFP를 이용하였으므로, 수신단에서는 GFP

reframing을 하기 위해서 VC 들 간에 위상을 정렬해야 함. 이를 위해서 버퍼를

사용하고 각 VC 들 간의 시간 차를 differential delay 라고 함.

A B C

A

B

C

X Y Z X Y Z X Y Z

X Y Z

Network

A

A B C

C

VC-Xv VC-Xv

VC-Xc VC-Xc

A

A

Differential delay = Max_Delay(A,B,C) – Min_Delay(A,B,C) in this figure


<50> KRnet 2003

VCAT : VC11/12 mapping GFP Capacity

VC12 frame VC11 frame

V5 R

32

R J2 R

32

R N2 R

32

R K4 R

32

R

V5 R

24

J2 R

24

N2 R

24

K4 R

24

R

F

F

F

F

500usec

125usec 34byte (2.176Mbit/s)

24byte+7bit (1.600Mbit/s)

VC12 프레임에 mapping 할 수 있는 GFP 데이터 량 = 32 byte + 2 byte (2.176Mbit/s)

VC11 프레임에 mapping 할 수 있는 GFP 데이터 량 = 24 byte + 7 bit (1.600Mbit/s)

F T1 Frame bit

Reserved Byte R

VC OverHead Byte

V5, J2, N2, K4

140byte 104byte


<51> KRnet 2003

LCAS : Introduction

MST_a(n)

RS-Ack_a

MFI_aSQ_n

CTRL_nGID_a

CRC_x

MFI_zSQ_p

CTRL_pGID_z

CRC_y

MST_z(p)RS-Ack_z

information sent in control packet x

of member_n in VCG_a

information ofmember n,VCG_a

VCG_a

member_n

VCG_zmember_p

SDH/OTN 망에서 Virtual Concatenation (VC)을 통해서 전송하는 컨테이너의 용량을 증가시키거나 감소시킬 때 사용하는 LCAS를 규정한다.

VC 그룹 (VCG) 내의 특정 멤버가 망내의 장애에 의해 서비스가 어려울 때 이 멤버를 제거하여 링크 용량을 자동적으로 줄이거나, 이 멤버의 장애가 제거되어 링크의 용량을 자동적으로 복귀시키는 기능도 규정한다.

본 규정에서는 VC 신호의 유연한 조정을 위해 Source측과 Sink 측 사이에 주고 받아야 하는 메시지와 Source측과 Sink 측에서 요구되는 상태를 규정한다.

특정 Application의 요구에 의해 VCG의 신호 용량을 증가시키거나 감소시킬 때 Hitless 를 보장할 수 있는 제어 메커니즘을 제공한다.

LCAS에서 사용하는 모든 제어는 G.707/G.709에서 정의한 Control Packet을 이용한다.

Higher Order LCAS for VC-n-Xv (n=3,4): H4 Byte

Lower Order LCAS for VC-m-Xv (m=11,12,2): Bit 2 in K4 Byte

OPUk-Xv (k=1,2,3) : column# 15 and Row# 1, 2, 3(VCOH1,2,3)


<52> KRnet 2003

LCAS : Control Packet & Control Words (General Case)

So Sk

Multi Frame

Indicator field (MFI)

Equal for all members of the VCG and will be incremented each frame

Used to realign the payload for all the members in the group and to calculate

the differential delay

Sequence

Indicator field (SQ)

Each member of the same VCG is assigned a unique sequence number,

starting at 0.

At initiation of a VCG source all member SQ shall be set to the highest possible

value.

Control field

(CTRL)

Used to transfer information from So to Sk

Used to synchronise the Sk with the So and provides the status of the

individual member of the group

Group

Identification bit

(GID)

All members of the same VCG has the same value in the frames with the same

MFI.

The pseudo-random pattern used is 215-1.

Sk So

Member status

field (MST)

Information from Sk to So about the status of all members of the same VCG

OK = 0, Fail = 1

Re-Sequence

Acknowledge bit

(RS-Ack)

Any changes detected at the Sk regarding the member sequence numbers is

reported to the So per VCG by toggling after the status of all members of the

VCG has been evaluated.

SoSk CRC field The CRC check is performed on every control packet after it has been received

The contents rejected if the test fails, and its contents are used immediately if

the CRC test passes.

Control Packet


<53> KRnet 2003

LCAS : Control Packet & Control Words (General Case)

Value

msb…lsb Command Remarks

0000 FIXED This is an indication that this end uses fixed bandwidth (non-LCAS

mode)

0001 ADD This member is about to be added to the group

0010 NORM Normal transmission

0011 EOS End of Sequence indication and Normal transmission

0101 IDLE This member is not part of the group or about to be removed

1111 DNU Do Not Use (the payload) the Sk side reported FAIL status

Control Words


<54> KRnet 2003

LCAS : Operations

The operation of LCAS is uni-directional.

Allow hitless addition/removal of bandwidth under control of NMS.

The removal of a member due to path level failures will in general not be

hitless for the service carried over the virtual concatenated group.

The autonomous addition of after a failure is repaired is hit-less.

The number of members in the VCG is only changed under NMS command.

Replacement of failed member in case of failure in Network cannot be

repaired

to be performed via a REMOVE – ADD sequence


<55> KRnet 2003

LCAS : Operations – Addition

Addition of member(s)

NMS request ADD member(s) in a VCG.

Assign SQ # greater than the n (n is the SQ # of member that has EOS in the CTRL)

Wait until MST of that member(s) is OK

The first member to respond with MST = OK shall be allocated the next highest SQ # (n+1) and shall change its CTRL to EOS coinciding with currently highest member changing its CTRL to NORM.

In case more than one member is being added and MST = OK being simultaneously received, then the allocation of SQ # is arbitrary.

Addition of member(s) payload

Send NORM/EOS in the control packet for that member

The first container frame to contain payload data for the new member shall be the container frame immediately following the container frame that contained the last bit(s) of the control packet with NORM/EOS message for that member


<56> KRnet 2003

LCAS : Addition of Member(s)

NMS LCAS Sk Sk Sk

CTRL=ADD

CTRL=ADD

CTRL=NORM CTRL=EOS

CTRL=NORM CTRL=EOS

MST=OK

MST=OK

mema(new) mema +1(new)memn-1(EOS)Note 1

Note 2

Note 3

Note 4

Note 5

Note 6

Note 7

Add cmnd

connectivity

checkconnectivitycheck

Not

e

Member n member a (new) Member a+1 (new)

CTRL SQ MST CTRL SQ MST CTRL SQ MST

1 Initial Condition EOS n-1 OK IDLE >n-1 FAIL IDLE >n-1 FAIL

2 NMS issues Add Cmnd to LCASC EOS n-1 OK IDLE >n-1 FAIL IDLE >n-1 FAIL

3 So (a) sends CTRL = ADD and SQ = n;

So (a+1) sends CTRL = ADD and SQ =n+1

EOS n-1 OK ADD n FAIL ADD n+1 FAIL

4 Sk (a) sends MS=OK to So EOS n-1 OK ADD n OK ADD n+1 FAIL

5 So (n-1) sends CTRL = NORM;

So (a) sends CTRL = EOS and SQ = n

NORM n-1 OK EOS n OK ADD n+1 FAIL

6 Sk (a+1) sends MST=OK to So NORM n-1 OK EOS n OK ADD n+1 OK

7 So (a) sends CTRL = NORM;

So (a+1) sends CTRL = EOS

NORM n-1 OK NOR

M

n OK EOS n+1 OK


<57> KRnet 2003

LCAS : Operations – Deletion

Deletion of member(s)

NMS request REMOVE member(s) in a VCG.

When a member is deleted,

SQ # and corresponding member status number of the other members shall be renumbered.

If the deleted member has EOS in its control packet, the next highest SQ # shall change its CTRL to EOS coinciding with deleted member’s CTRL with IDLE.

If member deletion occurs somewhere, then the other members with SQ # between newly deleted member and the highest SQ # shall update their SQ # coinciding with deleted member’s CTRL with IDLE.

Deletion of member(s) payload

When a member is deleted by sending an IDLE in the control packet,

The last container frame to contain payload data shall be the container frame that contained the last bit(s) of the control packet with IDLE message for that member.


<58> KRnet 2003

LCAS : Deletion of Last Member

NMS LCAS Sk Sk

MST=FAILRS-Ack inverted

memnmemn-1Note 1

Note 2

Note 3

Note 4

Decrease cmnd

CTRL=IDLECTRL=EOS

Note

Member n-1 Member n

CTRL SQ MST CTRL SQ MS

T

1 Initial Condition NORM n-2 OK EOS n-1 OK

2 NMS issues Dec Cmnd to LCASC NORM n-2 OK EOS n-1 OK

3 So (un-wanted) sends CTRL = IDLE, SQ = n-1,

So (n-2) sends CTRL = EOS

EOS n-2 OK IDLE n-1 OK

4 Sk (un-wanted) sends MST=FAIL, and RS-Ack bit

inverted to So

EOS n-2 OK IDLE n-1 FAI

L


<59> KRnet 2003

LCAS : Operations – Temporary Removal

Temporary Removal of member(s)

When failure is detected,

Sink will send in the MST of that member the status FAIL

Source will replace NORM to DNU or EOS to DNU and preceding member will send EOS in the CTRL code.

When failure is cleared,

Sink will send in the MST of that member the status OK

Source will replace DNU to NORM or DNU to EOS and preceding member will send NORM in the CTRL code.

Temporary Removal of member(s) payload

When failure is detected,

The last container frame to contain payload data for the removed member shall be the container frame that contained the last bit(s) of the control packet with DNU message for that member. The following frame will contains all ZERO in the payload area.

When defect is cleared,

The first container frame to contain payload data for the member shall be the container frame immediately following the container frame that contained the last bit(s) of the control packet with first NORM/EOS message for that member


<60> KRnet 2003

LCAS : Temporary Removal of Last Member

NMS LCAS Sk SkMST=FAIL

memn(EOS)memn-1Note 1

Note 2

Note 3

Note 4 Fail statusCTRL=DNUCTRL=EOS

Not

e

member n-1 member n (EOS)

CTRL SQ MS

T

CTRL SQ MS

T

1 Initial Condition NORM n-2 OK EOS n-1 OK

2 Sk (fault_mem) sends MST=FAIL to So NORM n-2 OK EOS n-1 FAI

L

3 So (fault_mem) sends DNU; So (fault_mem-1) sends EOS EOS n-2 OK DNU n-1 FAI

L

4 LCASC sends Fail status to NMS EOS n-2 OK DNU n-1 FAI

L


<61> KRnet 2003

LCAS : Temporary Removal & Restoration of Single (not last) Member

NMS LCAS Sk Sk Sk

CTRL=DNU

CTRL=NORM

MST=OK

MST=FAIL

mem4mem5(EOS)mem3Note 1

Note 2

Note 3Note 4

Note 5

Note 6

Note 7

Fail status

Sk

mem2

Not

e

member 2 member 3 Member 4 Member 5 (EOS)

CTRL S

Q

MS

T

CTR

L

SQ MS

T

CTRL S

Q

MS

T

CTR

L

SQ MS

T

1 Initial Condition NOR

M

1 OK NOR

M

2 OK NOR

M

3 OK EOS 4 OK

2 Sk (fault mem) send MST=FAIL to

So

NOR

M

1 OK NOR

M

2 OK NOR

M

3 FAI

L

EOS 4 OK

3 So (fault mem) send CTRL = DNU NOR

M

1 OK NOR

M

2 OK DNU 3 FAI

L

EOS 4 OK

4 See text below table NOR

M

1 OK NOR

M

2 OK DNU 3 FAI

L

EOS 4 OK

5 See text below table NOR

M

1 OK NOR

M

2 OK DNU 3 FAI

L

EOS 4 OK

6 Network Fault cleared MST = OK

sent to So

NOR

M

1 OK NOR

M

2 OK DNU 3 OK EOS 4 OK

7 CTRL changed from DNU to

NORM

NOR

M

1 OK NOR

M

2 OK NOR

M

3 OK EOS 4 OK


<62> KRnet 2003

EOS Services

Dedicated VCGs -High Cost Ethernet services -TLS -Point to point Shared VCGs -Low Cost Ethernet services -Point to Multi-point


<63> KRnet 2003

Metro Ethernet & Ethernet over SDH

Metro Ethernet

Rate limiting에 의한 서비스 대역폭 가변

End-to-End QoS 가 보장되지 않음 (Last Mile 까지만 접속 속도 보장)

Low cost Ethernet 서비스

Point-to-Point Service until completion of RPR Standard

TDM 서비스 제공 불가

기존 SDH망과의 연계가 불가 통신 사업자의 고민

Ethernet over SDH (EoS) of NG-SDH

Virtual Concatenation (VCAT)을 통해 2 Mb/s 단위로 다양한 크기의 회선 제공 가능

End-to-End QoS 보장 (TLS의 경우), POP까지의 QoS 보장 (IAS의 경우)

Low cost Ethernet (Shared VC) + High quality Ethernet (Dedicated VC)

Point-to-Point & Ring Configuration

TDM 서비스의 동시 제공 가능

99.999% 의 신뢰도를 갖고 있는 기존의 SDH network 사용

향후의 RPR에 대비한 GFP mapping 방식 채택


<64> KRnet 2003

EoS Network : Full SDH network

STM-16 Ring

STM-1

Sub. n

Sub. 1

Sub. n

Sub. 1

PABX

STM-1

GbE

Gigabit Ethernet Switch KORNET

IDC

EtherTransTM-1000

EtherTransTM-1000

EtherTransTM-1000

EtherTransTM-3000

EtherTransTM-3000

EtherTransTM-3000

현재의 SDH 기간망 (10G, BDCS,

DWDM)

10G

BDCS DWDM

Telephone Line


<65> KRnet 2003

김호건 [email protected]

Q & A

Thank You !!

ethernet over sonet - krnet.or.kr · 예) ethernet 신호가 10mbps 신호 이므로 이를...

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