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Quality of Service for Remote Control in the High Energy Physics Experiments: a Case Study. Tiziana Ferrari [email protected] INFN - CNAF. Overview. Quality of Service differentiated services architecture application characterization service definition and implementation

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Quality of service for remote control in the high energy physics experiments a case study

Quality of Service for Remote Control in the High Energy Physics Experiments: a Case Study

Tiziana Ferrari

[email protected]

INFN - CNAF

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Overview
Overview

  • Quality of Service

  • differentiated services architecture

  • application characterization

  • service definition and implementation

  • future work

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Quality of service problem statement
Quality of Service: problem statement

  • today: single service, best-effort

  • Service: type of “data” treatment during transmission across the network

    • qualitative

    • quantitative (delay, instantaneous delay variation, packet loss, throughput, MTU, congestion treatment)

  • Class: set of packets to which a given service applies

  • Benefits:

    • congestion management

    • differentiated allocation of expensive network resources (ISP)

    • application: differentiated treatment of streams according to their requirements and priority

    • guarantees of congestion independent parameters (e.g. delay variation)

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Differentiated services
Differentiated services

  • Why the differentiated services (diffserv)?

    • independent of layer 2 technologies

    • interoperability between independent national research networks (different requirements, infrastructures, policies and management)

    • traffic aggregation

    • scalability

    • nosignalling

    • QoS for networks not ATM based

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Diffserv architecture components
Diffserv architecture components

  • DS field (1 byte) - IP header -

  • packet classification

  • packet scheduling

  • traffic conditioning:

    • metering

    • marking

    • policing

    • shaping

0

6

7

CU

DS field

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Diffserv architecture phbs
Diffserv architecture: PHBs

  • Per Hop Behaviours: description of the packet treatment into the network

  • Standardised PHBs:

    • Expedited Forwarding (low delay, low delay variation,

      guaranteed bandwidth)

    • Assured Forwarding (Behaviour Aggregate, 4 classes,

      3 drop priorities per class)

  • Experimental PHBs

  • PHB class selectors: XXX000 (backward compatibility with TOS precedence)

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Diffserv architecture network model
Diffserv architecture: network model

DS region

DS domain

DS domain

ATM

MPLS

Non-DS capable

domain

DS domain

Marking

policing

scheduling

Core domain

marking

shaping

DS domain

DS domain

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Application characterization
Application characterization

Goal:

identification of the application requirements for

service definition

  • Trigger hardware remote control

  • Monitoring: quality and correctness of analysis results

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Application 1 trigger hardware remote control

Server 1

VME

Client 1

Server 2

Client 2

VME

R1

R2

R3

Client 3

...

...

VME

Client n

Server m

bottlenecks

Application 1: trigger hardwareremote control

  • ROBIN

  • client - server, duplex exchange of data, interactive

  • few transactions (low bandwidth)

  • TCP ports and IP address of the server known

  • one-way delay sensitiveness

  • high reliability (packet loss probability, bandwidth)

  • burst tolerance

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Application 2 analysis monitoring

server

...

bottleneck

Application 2: Analysis monitoring

  • exchange of analysis results (root object)

  • duplex, asymmetric traffic volume

  • low bandwidth consumption

  • client - server,

  • TCP, IP address of server and clients known

  • packet loss tolerant

  • minimum bandwidth guarantee per client

  • dynamic allocation of the maximum overall capacity allocated

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Service level specification sls 1
Service Level Specification (SLS) - 1

  • Hardware remote control:

    • packet classification and marking (at the edge):

      if (pack(src) = (s1 || s2 || … || sm) &&

      pack(dst) = (d1 || d2 || … || dn) &&

      protocol = TCP && pack(port)[x, y] )

      then label(pack) = max precedence

    • bandwidth guarantee (through policing):

      max service rate = 64 Kbps * Nsrc

      64 kbps: estimated rate consumed by 1 server/client

      Nsrc: number of servers (upstream) of clients (downstream)

      if (traffic <= max && burst <= 64 kby) then

      label = Expedited Forwarding

      else label = best-effort

    • one-way delay (through scheduling):

      priority queuing

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Service level 1 implementation
Service Level - 1: implementation

PQ

VME

Client 1

R

PQ

r

Server 1

PQ

Client 2

R

PQ

PQ

VME

PQ

PQ

r

PQ

Server 2

PQ

PQ

R

Client 3

...

PQ

VME

r

PQ

Client 4

Server 8

PQ

Client  server:

scheduling

marking

traffic, max rate R

Server client:

policing

scheduling

marking

traffic, max rate r

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Service level specification 2
Service Level Specification -2

  • Analysis monitoring:

    • server  client:

      • packet classification and marking (at the edge):

        if (pack(src) = s&& pack(dst)=(d1 || d2 || … || dn) &&

        protocol = TCP)

        then label(pack) = PHB  Assured Forwarding(AF)class

      • bandwidth guarantee (through policing):

        max service rate per client = 256 Mbps

        min rate per client: 64 kbps

        for each client:

        if (traffic <= min && burst <= 16 Kby) then label = AF11;

        else if (traffic <= max) then label = AF12;

        else drop(packet)

      • scheduling: Weighted Fair Queuing

      • traffic differentiation: Weighted Random Early Discard

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Service level specification 2 cont
Service Level Specification -2 (cont)

  • Client  server:

    • packet classification and marking (at the edge):

      if (pack(src) = di && pack(dst) = s && protocol = TCP)

      then label(pack) = PHB  Assured Forwarding(AF)class

    • bandwidth guarantee (through policing):

      max service rate = 5 Mbps

      min rate per client: 64 kbps

      for each client:

      if (traffic <= min && burst <= 16 Kby) then

      label = AF11;

      else label = AF12;

      if (traffic(Af12) <= max) then OK

      else drop(packet);

    • scheduling: Weighted Fair Queuing

    • traffic differentiation: Weighted Random Early Discard

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Service level 2 implementation
Service Level -2: implementation

r

WFQ

Client 1

WFQ

r

WFQ

Client 2

R

WFQ

WFQ

WFQ

r

Server

WFQ

WFQ

WFQ

Client 3

r

WFQ

Client 4

WFQ

scheduling

marking

Client  server:

traffic, max rate R

policing

scheduling

marking

traffic, max rate r

Server client:

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Scheduling pq vs wfq
Scheduling: PQ vs WFQ

Priority Queuing:

absolute precedence over any other queue

one-way delay minimization

WFQ: distribution of bandwidth between queues according to the weight

associated to each of them

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


Future work
Future work

Fermilab

Test site 1

ESnet

diffserv Testbed

European diffserv testbed

or ATM p-2-p link

Test site 1

...

Test site 1

  • Testbed configuration

  • tuning of router configuration

  • validation of the EF : priority queuing, burstiness and scheduling

  • validation of the AF implementation: WRED configuration

Quality of Service for Remote Control in the High Energy Physics Experiments

CHEP, 07 Feb 2000


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