RobertoBifulco.it

  • topics
  • publications
  • il gatto
  • account
Home › Reti di Calcolatori 2 › Capitolo II - Techniques and architectures for QoS

II.2Service Specification

Roberto Bifulco — Fri, 10/17/2008 - 22:39

Visto che non è possibile prevedere a priori il traffico dati, poiché è composto da componenti eterogenee e variabili, è necessario fornire una specifica del servizio che si richiede alla rete sulla base di alcuni parametri:

  • Loss: probabilità che un pacchetto del flusso vada perso;

  • Delay: il tempo impiegato da un pacchetto per andare dalla sorgente alla destinazione;

  • Delay jitter: la massima differenza fra i ritardi subiti fra due pacchetti del flusso;

  • Bandwidth: la massima velocità a cui la sorgente può inviare dati.


 

Sulla base di questi parametri l'end system e la rete stabiliscono un contratto, il Service Level Agreement, in cui entrambe le parti si impegnano a dare delle garanzie. Chiaramente sono previsti anche meccanismi per verificare che il contratto, e dunque le garanzie, siano rispettati. Nel seguito sono riportati alcuni esempi di contratto:

  • Hard Real Time: servizio garantito

    • Contratto:

      • Dalla rete al client: è garantito un limite superiore deterministico al delay per ogni pacchetto della sessione;

      • Dal client alla rete: si garantisce che nella sessione non viene inviato più traffico di quanto specificato;

    • Supporto algoritmico:

      • Controllo di ammissione basato sull'analisi del caso peggiore;

      • Classificazione e scheduling del traffico per flusso a livello dei router;

  • Soft Real Time: servizio a carico controllato

    • Contratto:

      • Dalla rete al client: è garantito un livello di performance simile a quello di una rete best-effort con poco traffico;

      • Dal client alla rete: si garantisce che nella sessione non viene inviato più traffico di quanto specificato;

    • Supporto algoritmico:

      • Controllo di ammissione basato sulla misurazione di aggregati;

      • Scheduling per aggregati.

‹ II.1QoS problems up II.3Traffic and Service Characterization ›
  • Printer-friendly version

nfl jerseys suppliers Fashion

Anonymous (not verified) — Mon, 01/02/2012 - 08:16

nfl jerseys suppliers Fashion brand
wholesale coach bags the trend of fashion
coach outlet Don't miss the chance it's very good
coach outlet store comfortable with it
wholesale designer handbags well known great
coach handbags outlet attractive and reasonable price
cheap coach online shopping
coach outlet store may most likely need
coach handbag outlet A good thing
authentic nfl jerseys for sale fashion designed
cheap authentic nfl jerseys together with lifestyle

  • reply

nfl jerseys

mostnfl (not verified) — Fri, 12/30/2011 - 14:30

New England Patriots Jerseys
Authentic New England Patriots Jerseys
Patriots Jerseys Sale
Premier New England Patriots Jerseys
Tom Brady Jersey
Wes Welker Jersey
Chad Ochocinco Jersey

  • reply

nfl jerseys

mostnfl (not verified) — Thu, 12/29/2011 - 09:39

Vernon Davis Jersey ,Joe Greene Jersey Why dont they just Sedrick Ellis Jersey reverse it Jason Pierre Paul Jersey instead Jeremy Maclin Jersey of the blue home and Jason Witten Jersey red away, make Jay Cutler Jersey it red home and blue away, alternate it year-to-year

  • reply

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Allowed HTML tags: <a> <em> <strong> <cite> <code> <ul> <ol> <li> <dl> <dt> <dd>
  • Lines and paragraphs break automatically.

More information about formatting options

CAPTCHA
This question is for testing whether you are a human visitor and to prevent automated spam submissions.
Image CAPTCHA
Enter the characters shown in the image.

Reti di Calcolatori 2

  • Introduzione
  • Capitolo I - Networks Evolution
    • Communication models
      • Circuit switching
      • Packet Switching
      • Flow Switching
    • A rapidly changing scenario
    • Data and media taxonomy
  • Capitolo II - Techniques and architectures for QoS
    • II.1QoS problems
    • II.2Service Specification
    • II.3Traffic and Service Characterization
      • II.3.1Token Bucket
      • II.3.2Leaky Bucket
      • II.3.3Queue management
      • II.3.4Scheduling
        • II.3.4.1Scheduling policies
        • II.3.4.1.1GPS
    • II.4Parekh-Gallager Theorem
    • II.5QoS Architectures
      • II.5.1Integrated Services (IntServ)
        • II.5.1.1RSVP
        • II.5.1.2IntServ today
      • II.5.2Differentiated Services (DiffServ)
        • II.5.2.1PHB: Expedited Forwarding
        • II.5.2.2PHB: Assured Forwarding
    • II.6QoS in Fast Interconnect
      • II.6.1Flow Control
        • II.6.1.1Flow Control in IBA
        • II.6.1.2Flow Control in ASI
        • II.6.1.3Flow Control in Ethernet
      • II.6.2Congestion control
        • II.6.2.1Congestion Control in IBA
        • II.6.2.2Congestion Control in ASI
  • Capitolo III - Inter-domain routing with BGP
    • III.1Intra-Domain Routing
      • III.1.1Distance Vector
      • III.1.2Link State
    • III.2Inter-domain routing
      • III.2.1Border Gateway Protocol (BGP)
        • III.2.1.1BGP Messages
        • III.2.1.2BGP Example 1
        • III.2.1.3Route preference
        • III.2.1.4The internet organization
        • III.2.1.5BGP in large networks
        • III.2.1.6Confederations
        • III.2.1.7Route Reflectors
        • III.2.1.8The dynamics of BGP
        • III.2.1.9BGP routing tables
        • III.2.1.10The route selection process
  • Capitolo IV - Asynchronous transfer mode
    • ATM architecture
    • ATM Protocol Stack
    • ATM Addressing
    • ATM Quality of Service
    • ATM Adaptation Layer
    • Call and Connection Control
    • ATM in LAN
    • IP over ATM
  • Capitolo V - Multi Protocol Label Switching
    • MPLS
  • Capitolo VI - Traffic Engineering
    • IP-based Traffic Engineering
    • MPLS-based traffic engineering
  • Capitolo VII - SDH/SONET
  • Capitolo VIII - IP su reti ottiche
    • DWDM
    • Generalized Framing Procedure (GFP)
    • Gigabit Ethernet (GbE)
    • IP-centric control of optical networks
  • Capitolo IX - Network Management
    • Simple Network Management Protocol (SNMP)
    • Network management applications
    • Professional and Business Challanges
    • Service life-cycle
    • Provisioning level Agreement
  • Capitolo X - Network Resiliency
    • Network recovery
    • Recovery Mechanisms Control
  • Capitolo XI - Network security
    • Types of Attack
    • Firewall
    • NAT
    • Intrusion Prevention Systems
  • Download
  • topics
  • publications
  • il gatto
  • account