RPR Media Access Control and >> Client Design€¦ · RPR Media Access Control and Client Design...

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>>Sanjay, Jeanne, Adisak, Harry Sept 12, 2001. IEEE 802.17

RPR Media Access Control and Client Design

Sanjay K. Agrawal, LuminousJeanne De_Jaegher, AlcatelHenry Hsiaw, NECAdisak Mekkittikul, LanternHarry Peng, NortelRobin, Vitesse

>> Sanjay, Jeanne, Adisak, Harry, Sept 12, 2001. IEEE 802.172

Components of a complete RPR proposal

Topology Discovery

Protection Switching

RPR MAC

MAC Service Definition

Media Access Control

Frame Format

Transit Path

Bandwidth Mgmt.

OAM and Layer Mgmt

Bridging

PHY interfaceEthernet

SONET/SDH

jcf_topo_0x.pdf

jal_prot_0x.pdf

am_mrm_0x.pdf

hp_bwmgnt_0x.pdf

rb_phys_0x.pdf

hp_grs_0x.pdf

cb_layer_01.pdf

hp_brcom_01.pdf

rs_frame_0x.pdf

sa_transi_0x.pdf

ib_oamp_01.pdf


Outline? Introduction

? Objectives and requirements

? Issues meeting the requirements

? RPR Framework Proposal

? RPR MAC Media Access Rate control

? RPR MAC Client Interface Requirements

? RPR MAC Client Options

? Conclusion


Introduction

Discuss the MAC behavior and interfaces with other blocks that address

? Approved Objectives.

? Service requirements.

? Implementation flexibility, under interoperability constraints.


RPR MAC relevant voted objectives

? The MAC shall support multiple types of service

? The 802.17 standard shall provide support for services that require bounded delay and jitter, and guaranteed bandwidth.

? The 802.17 standard shall support dynamic weighted bandwidth distribution


MAC Functionality Requirements? MAC should support ?Multiple type of services?Committed bandwidth services endorsed by carrier

SLAs ?Overcommitted bandwidth services

?MAC should provide services with bounded delay.? Support arbitrary source destination traffic flows into the

RPR shared medium.? Committed bandwidth services should be never

penalized in all circumstances.? Carrier network services for metro and core? Maximum link utilization? Maximum spatial reuse


Bandwidth management Issue

? If MAC architecture allows lower class services interfering or even blocking the committed data services as a result of congestion, ? carrier SLA can be violated.


Support for Virtual Output Queuing? Problems if MAC proposal has no VoQ support:? Bandwidth management: MAC sets the access rate low to

satisfy the bandwidth allocated by one congested destination ?Severely limits the access rates to other uncongested

destinations. ?MAC client: (HoL) blocking problem occurs in a single

queue access. ?Frame destined to uncongested destination waits

behind an frame congested destinations.? Low priority streams can congest a destination, as a

result committed bandwidth to all destination can suffer.(violation of SLA’s)


Proposed Solution

? Bandwidth management propagates independent media access rate control for each ring segment in the RPR MAC. ?Monitors committed and overcommited bandwidth

separately.

?Media Access control controls the access of overcommitted traffic into the media, such that congestion is avoided.

? Support for Virtual Output Queuing (VoQ) in the MAC client.


RPR MAC Framework and RelevantQoS Components

Reconciliation Sublayer(Ethernet/SONET)

Reconciliation Sublayer(Ethernet/SONET)

PHY (Ethernet/SONET)PHY (Ethernet/SONET)

MLME

RPR MAC Control

Topology(Topology DB, State

Machine, etc.)

Protection(Steering DB, State

Machine, etc.)

Ringlet Selection

MAC Client(s)MAC Client(s)

Media Access Rate Control /

Policer

Transit Data Path

RPR Media Access Control

FCS

(PSAP)

(PSAP)

(MLSAP)

(MLSAP)

(MSAP)(RMSAP)

MAC Layer

Boundary

OAMP

BW monitoring


Media Access Rate Control

? Bandwidth management block monitors the transit bandwidth and advertises link availability as RCM message.

? Every node in a distributed fashion determines the weighted fair share:?Maximum bandwidth contribution of a given source

node for every link segment in a ringlet is determined. ? At every node, RPR MAC controls bandwidth access from

the MAC client into the media on per link segment basis tpavoid congestion.


Support for RPR VoQ MAC client? Enhanced client implement Virtual Output Queuing functionality to

avoid Head of Line (HoL) blocking. ? Traditional Clients: do not implement virtual output queuing:

?LLC client?Bridging client?Routing client?Other clients

? Need to serve multiple types of clients ?Traditional services with no VoQ.?Traditional services with VoQ.?New services with VoQ.

Compatibility to traditional clients while supporting the new clients very important.


RPR MAC and Client Interaction

TransitBuffer

Add PassArbiter

RPR MAC Transit Blocks

Ringlet iOut

Ringlet iIn

MediaAccessRate

Policing

MACClient

RPR MAC

HeaderProcessing

Data.request

Data.indicate

Control.request

Control.Indicate


Media access control signalsThere are two type of MAC_control.indication RPR MAC

conveys to the MAC clients:? Pause signal: The pause signal indicates: ? One of the link segment bandwidth is violated. ? Link segment number.

? RCM signal: The RCM message indicates to the MAC: ? Bandwidth available on per link segment basis. ?MAC client has a choice of using the RCM information

to shape the traffic before sending it into the RPR MAC.?Avoids pause signals.

The pause signal and RCM signal overlap in terms of functionality?Both necessary to serve traditional and the new clients.


RPR MAC Client: Traditional Clients

single queue forall destinations

RPR MAC

Ringlet iOut

Ringlet iIn

AddTraffic

DropTraffic

Block

MediaAccessRate

Policing

MACClient

MAC

Pause,congested link numRCM


New MAC Client : Virtual Output Queuing

Per destination shaper+ multicast shaper

+ weighted schedulerfor ringlet i

RPR MAC

Ringlet iOutRinglet i

In

AddTraffic

Desitnation NDesitnation 0

Block

MediaAccessRate

Policing

MACClient

MAC

Multicast


MLME

RMSAP


New MAC Client : Virtual Output Queuing

Per destination shaper+ multicast shaper

+ weighted schedulerfor ringlet i

RPR MAC

Ringlet iOut

Ringlet iIn

AddTraffic

Desitnation NDesitnation 0

Traffic Shaper

MediaAccessRate

Policing

MACClient

MAC

Multicast


MLME

RMSAP

?Sharing target available link segment bandwidth in the ring between multiple destination flows traversing that link.


New MAC Client Class of Service based queuing per destination

Ringlet MAC

Per destination class basedqueuing +multicast queueing,class based scheduling + per

destination shaper+ weighted scheduler

for ringlet i

Ringlet iOut

Ringlet iIn

AddTraffic

DropTraffic

StrictPriority

Class 7 Class 0Class 7 Class 0

Class 7 Class 0

Traffic Shaper

MediaAccessRate

Policing

MACClient

MAC

Class 7 Class 0


MLME

RMSAP


Conclusion

? Conforms to the 802 shared MAC architecture.

? Supports carrier class services.

? Virtual Output Queuing to avoid HOL blocking.

? Supports traditional simple clients: LLC, Bridging, Routing as well as new client that avoid HoL blocking.

? Scalable for high-link speeds and cost effective.


Media Access Rate ControlAt each 10usec interval

for each link segmentcalculate the node (for this MAC) allowed BW, fj.

fj = rj + wj*RCFgive credit for each segment

if ( segment_credit) < 15,000,000segment_credit += fj

if ( segment_credit) < 0 // client BW exceeds limitassert PAUSE.indicate

end FORAt each DATA.request

if no PAUSE.indicate asserted, accept DATA.requestfor each segment between this and the dest nodes

deduct segment creditsegment_credit -= frame_length*10,000

end FOR


RPR Network

RPRMac

Node 0RPRMac

Node 2RPRMac

Node 3RPRMac

Node 4

RPRMac

Node N -1RPRMac

Node N-2

RPRMac

Node 5RPRMac

Node N/2

RPRMac

Node N/2+1

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