02a ATM Resource Management Ds

1

ATM Resource Management for RNC


Objectives

At the end of this module the participant will be able to:

• Explain important ATM transmission parameters.

• Create ATM resources for various Interfaces.

• Create Virtual Path and Virtual Channel Link Termination Points (VP/VC).

• Explain traffic descriptors, service class and QoS parameters.

Reference: ATM Resource Management for RNC (dn02142996),

ATM services (dn03481353)

2



Why ATM for 3G?

• ATM provides efficient support for transmission of voice, data, and video

• ATM provides QoS guarantee and reliability

• ATM utilises statistical multiplexing, so• Less bandwidth can be reserved• Transmission cost saving are considerable

• ATM supports the soft handover functionality

3



ATM in Brief

Flow of ATM cells

Payload(48 byte)

ATM Cell (53bytes)

Header(5 byte)

Virtual Path (VP)

Virtual Channel (VC)

Transmission Path(e.g STM1, n x E1)

4



ATM Cell

GFC Generic Flow ControlVPI Virtual Path IdentifierVCI Virtual Channel Identifier

PT Payload TypeCLP Cell Loss PriorityHEC Header Error Control

User Network Interface (UNI)Network Node Interface (NNI)

VCI

GFC VPI

VPI

VCI

VCI PT CLP

HEC

123457 68

VCI

VPI

VPI

VCI

VCI PT CLP

HEC

123457 68

Payload Payload

Header(5 bytes)

Payload(48 bytes)

Provides local functions, such as identifying multiple stations that share a single ATM interface

The 1st bit - indicates whether the cell contains user data or control dataThe 2nd bit - indicates congestion

Indicates two levels of priority for ATM cells, CLP=1 should be discarded in preference to cells with the CLP=0

5



ATM over E1

Header Payload

ATM cell

0 1 2 16 1817 3115

TS0TS1-15

TS16TS17-31

. . . . . .

0 1 2 16 1817 3115

TS0TS1-15

TS16TS17-31

. . . . . .

E1 frameE1 frame

E1 (2048 kbit/s) -> 4528cells per second.

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ATM over SDH

STM-1 (155,52 Mbps) can fit 44.15 cells per frame -> 353 207 cells per second.

Section

Overhead ...

260 bytes

9 bytes

P

O

H

9 bytes VC-4

VP1

VP2

VP3

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Virtual Channel and Virtual Path Switching

VPI 1

VPI 3

VPI 2

VPI 4 VPI 5

VP switch

Port

VCI 21

VCI 22

VCI 21

VCI 22

VCI 24

VCI 23

VCI 21

VCI 22

VC switch

Port

Port

Incoming Outgoing

VPI 1/VCI 21 => VPI 3/VCI 23VPI 1/VCI 22 => VPI 2/VCI 24VPI 4/VCI 21 => VPI 5/VCI 21VPI 4/VCI 22 => VPI 5/VCI 22

VCI21

VPI1DATA VCI

24VPI2DATA

VCI22

VPI1DATA VCI

23VPI3DATA

VCI21

VPI4DATA VCI

21VPI5DATA

VCI22

VPI4DATA VCI

22VPI5DATA

8



Creating ATM Resources

ATM resource management is used for creation and configuring the logical resources for ATM virtual connections.

• Creation of ATM Interface related to a physical layer TTP.

• Creation of the access profile of ATM Interface.

• Creation of VP link termination point.

• Creation of VC link termination point.

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Creating an ATM Interface• External logical interface in which the connections

are set up.

• MML command: ZLAC

• Related parameters:

•Interface ID (1…588, chosen by system if not given).

•Interface type (UNI, User Network Interface / NNI,

Network Node Interface).

•Related Physical Layer Trail Termination Point.

•Administrative State: locked or unlocked.

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Creating Access Profile of ATM Interface

• The access profile created for an ATM interface defines the connection structure build under that ATM interface.

• MML command: ZLAF

• Related parameters:

• ATM Interface ID.

• Maximum ingress and egress transmission

bandwidth (provided by the system)

• Maximum number of VPI bits.

• Maximum number of VCI bits.

• UPC/NPC mode.

11



Creating VP/VC Link Termination Points (Ltp)

• Termination Points are the terminating ends of the VP/VC connections, defining use and characteristics of VP/VC connections.

• MML command: ZLCC

• Important parameters:

•Related ATM IF ID.

•Type (VP or VC).

•Identifier (VPI or/and VCI).

•Traffic Parameters (PCR – Peak Cell Rate, CDVT_PCR – Cell

Delay Variation Tolerance related to PCR).

•Service Category (CBR/UBR - constant or unspecified bit rate).

•QoS class.

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Service Classes, Traffic and QoS Parameters

divide connections into classes according to real time, non-real time, bursty, etc.

define the bandwidth requirements

define the Quality of Service (QoS) of the connection: delay, cell loss, etc.

13



ATM Traffic Parameters (Descriptors)

• The Traffic Descriptors describe traffic characteristics of a source. The traffic descriptors are the generic list of traffic parameters, which describe the traffic characteristics of an ATM connection.

•Peak Cell Rate (PCR).

•Sustained Cell Rate (SCR).

•Maximum Burst Size (MBS).

•Minimum Cell Rate (MCR).

•Cell Delay Variation Tolerance (CDVT).

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ATM Traffic Parameters

MCR

Cell Rate

PCR

SCR

Line Rate

t

MBS

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ATM Layer Service Categories

•CBR (Constant Bit Rate).

•rt-VBR (real time Variable Bit Rate).

•nrt-VBR (non-real time Variable Bit Rate).

•ABR (Available Bit Rate).

•UBR (Unspecified Bit Rate).

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Constant Bit Rate• For the connections that request a static amount of

bandwidth that is continuously available during the connection lifetime.

• Is intended to support real time applications requiring tightly constrained delay variation.

• The applications are e.g. video, audio, circuit emulation, but use of CBR is not restricted to those applications.

• Traffic parameters are specified: PCR, CDVT

• Rate guaranteed: PCR

Time

Bandwidth

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Real Time Variable Bit Rate • Is intended for real time applications, that is, those

requiring tightly constrained delay and delay variation.

• Generally the applications needing the rt-VBR are named as "bursty".

• Traffic parameters are specified: PCR, SCR, MBS, CDVT

• Rate guaranteed: SCR

Time

Bandwidth

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Non-Real Time Variable Bit Rate• Is intended for non-real time applications, which

have bursty traffic characteristics without tight delay requirements.

• No delay bounds are associated.

• Traffic parameters are specified: PCR, SCR, MBS, CDVT

• Rate guaranteed: SCR

Time

Bandwidth

19



Available Bit Rate

• Is intended for non-real time applications having ability to reduce or increase their information rate if the network requires them to do so.

• The aim of ABR service is to dynamically provide access to bandwidth currently not used by other service categories to users who can adjust their transmission rate.

• A flow control mechanism is specified.

• Applications for ABR are:•LAN interconnection•high performance file transfer•web browsing

• Traffic parameters are specified: PCR, MCR, CDVT

• Rate guaranteed: MCR

20



Unspecified Bit Rate• Is intended for non-real time applications, that is,

those not requiring tightly constrained delay and delay variation.

• Examples of applications are traditional computer communication applications, such as file transfer and e-mail.

• Service does not specify traffic related guarantees.

• Known as “best effort” traffic.

• Traffic parameters are specified: PCR, CDVT

• Rate guaranteed: No guarantees

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Service Category Attributes and Guarantees

Servicecategory

Traffic description

Guarantees

Min Loss (CLR)Delay/Variance Bandwidth

Use of feedbackcontrol

Application

CBR

rt-VBR

nrt-VBR

ABR

UBR

PCR, CDVT

PCR, SCR, MBS, CDVT

PCR, MCR, CDVT

-

PCR, SCR, MBS, CDVT

YES YES YES NO

YES

YES

YES

NO

YES

NO

NO

NO

YES

YES

YES

NO

NO

NO

YES

NO

Circuit emulation, video conference

VBR video, silence suppressed voice

Critical data (e.g.airline reservation, banking transactions), signalling

Native ATM, Frame Relay over ATM, LAN

LAN, email,file transfer

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Suitability

Applications

Critical data

LAN interconnection

WAN data transmission

Circuit emulation

Telephony, videoconf.

Compressed audio

Video distribution

Interactive multimedia

CBR

Good

Fair

Fair

Best

Best

Fair

Best

Best

rt-VBR

Fair

Fair

Fair

Good

-

Best

Good

Best

nrt-VBR

Best

Good

Good

No

-

Good

Fair

Good

ABR

Fair

Best

Best

No

No

Good

No

Good

UBR

No

Good

Good

No

No

Fair

No

Fair

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ATM QoS Parameters

• Negotiated QoS parameters:

•Cell Delay Variation (CDV).

•Maximum Cell Transfer Delay (max CTD).

•Cell Loss Ratio (CLR).

• Not negotiated QoS parameters:

•Cell Error Ratio (CER).

•Severely Eroded Cell Block Ratio (SECBR).

•Cell Misinsertion rate (CMR).

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QoS Class Objectives (ITU-T I.356)

QoS parameter Note QoS class 1 QoS class 2 QoS class 3 U class

CTD Mean Value 400 ms Unspecified Unspecified Unspecified

CDV 2 point 10-8 quantile 3 ms Unspecified Unspecified Unspecified

CLR(0+1) Applies to CLP=0+1 3 * 10-7 10-5 Unspecified Unspecified

CLR(0) Applies to CLP=0 N/A Unspecified 10 -5 Unspecified

CER Upper Bound 4 * 10-6 4 * 10-6 4 * 10-6 Unspecified

CMR Upper Bound Once per day Once per day Once per day Unspecified

SECBR Upper Bound 10-4 10-4 10-4 Unspecified

Note:The ITU-T may change these objectives to better or worse values based upon actual operational experience.

25



ATM Traffic Management Functions

• Traffic Policing (UPC/NPC user-network parameter control) – set of actions for monitoring and controlling the incoming ATM traffic and performing necessary actions.•Dual leacky bucket algorithm.

• Connection Admission Control (CAC) – used for checking bandwidth and resources for requested connection.

• Traffic Shaping - mechanism for delaying (buffering) cells in accordance with the traffic parameters.

• Cell loss priority control – mechanism that uses CLP marking of the cell.

• Frame Discard – mechanism for discarding cells if a network is congested.•Partial Packet Discard (PPD) algorithm.•Early Packet Discard (EPD) algorithm.

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Dual Leaky Bucket

ExcessRate

ATM cellATM cell ATM cellATM cell ATM cellATM cell

CLP=0

ContractedRate

CLP=1

Cells Discarded

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General Placement of Traffic Policing and Shaping

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Partial Packet Discard (PPD)

Buffer positions for cells

PPD discards cells

When the buffer reaches the capacity, PPD discards the remaining cells, except the last one.

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Early Packet Discard (EPD)

When the buffer level exceeds the EPD threshold, the cells are selectively discarded from the entire frames.

EPD discards frames

Buffer positions for cells

EPDThreshold

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Summary: Creating ATM Transport Resources

Configure PETs / SETsZYE.. / ZYA ..

Create IMA-GroupZYBC

Create Trail Termination PointZYDC

PET SET

Create ATM IFZLAC

Attach Access ProfileZLAF

Create VPs and VCsZLCC

ZYE.. / ZYA ..

ZYBI

ZYDI

ZLAI / ZLAJ

ZLAQ

ZLCI

Delete VPs ZLCDLock VPs ZLCSDelete VCs ZLCDLock VCs ZLCS

Delete ATM IF ZLADRemove Access Profile ZLAELock ATM IF ZLAS

Delete IMA Group ZYBD

Delete Path trace ZYAD

Delete TTP ZYDD

Delete

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UTRAN RNC

RNC

WBTS(Node B)

WBTS(Node B)

MGW

SGSN

Iub-IF

Iu-CS-IF

Iu-PS-IF

UNI

NNI

NNI

NNI

UBRCBR

CBR

IPOAMMTP3SLAAL2UD

ICSU

SFU

MTP3SL

IPOAUD

CBRUBR

UBRCBR

CBR

CBR

CBR

IPOAM

AAL2SIG

D-NBAP

C-NBAP

AAL2UD 1x pro WAM

1x pro WAM

1x pro SITE

1x pro WAM

CB

R

Iur-IF

CB

R

AA

L2U

D

MTP3

SL

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ATM Resource Management for Iu-CS IF

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ATM Resource Management for Iu-PS IF

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ATM Resource Management in Iur IF

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ATM Resource Management for Iub IF

Date post:	09-Dec-2015
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02a ATM Resource Management Ds

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