11 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. QOS Module 12

22 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Points clés du module Les trois raisons d’échec de la voix Les précautions nécessaires pour réussir avec la VoIP Implémenter la VoIP sur des LANs

33 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Sommaire Contrôle du délai Sources du délai Contrôle de la jigue Fonction LFI Contrôle de la sérialisation du délai Process de compression de l’en-tête RTP Contrôle du délai de Queuing

44 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Contrôle du délai ITU’s G.114 recommendation: 0 to 150 (ms) one-way delay Time (ms) Walkie talkie One hop satellite Put the old PBX back in now. Interactive Delay target PBX VOIP

55 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Les sources du délai G.729 look ahead 20 ms packet 20 ms 5 ms Processing 10 ms 61 ms 1,500 byte data packet 7.8 ms 66 byte voice packet.33 ms 66 byte voice packet.33 ms G ms Processing 10 ms ms total Jitter buffer 40 ms Serialization Queuing Network Serialization Queuing 1,500 byte data packet 7.8 ms

66 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Délai de traitement du codec Codec Rate Sample Size Sample Size Best Case Best Case Worst Case Worst Case

77 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Délai de l’algorithme Codec Algorithmic Delay

88 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Délai de paquetisation PCM, G Kbps ADPCM, G Kbps CS-ACELP, G Kbps MP-MLQ, G Kbps MP-ACELP, G Kbps Coder Payload Size (Bytes) Payload Size (Bytes) Packetization Delay (ms) Packetization Delay (ms) Payload Size (Bytes) Payload Size (Bytes) Packetization Delay (ms) Packetization Delay (ms)

99 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Le délai de serialisation Taille de la trame (octets ) Vitesse de la ligne (Kbps)

10 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Délai de queuing 56 Kbps Line 214 ms serialization delay for 1500-byte frame at 64 Kbps Real-time MTU Elastic MTU InOut

11 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Gestion de la jigue VVVVVVV Voice frames sent to the Network Dejittered voice frames to DSP VVV VVVVVVVVVV The voice packets were sent with 20 millisecond spacing. VVVVVVVVVV Delay in ms Jitter Variation ranges from +10 to –25 = 35 ms jitter

12 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute.

13 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Exemple de latence LFI 1,500 byte data packet 214 ms 66 byte voice packet 10 ms 1,500 byte data packet 214 ms 66 byte voice packet 10 ms 597 ms total 61 ms G.729 look ahead 20 ms packet Processing G.729 Processing Jitter buffer Serialization Queuing Network Serialization Queuing 20 ms 5 ms 10 ms 3 ms 10 ms 40 ms

14 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Multilink PPP avec LFI 56 Kbps link Elastic MTUReal-time MTU Addendum to PPP specification 214 ms serialization delay for 1,500 byte frame at 64 Kbps 56 Kbps link Elastic MTU Real-time MTU Elastic MTU InOut InOut

15 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Fonctionnement du LFI LLQ Classify Low latency queuing LLQ LFI Traffic destined for interface 1,500 byte Ethernet frame Voice packets Classification by port and socket Fragment size based on serialization delay Fragmented frames interleaved with time- sensitive traffic

16 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute.

17 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Gestion du lien Gigabit Gigabit Ethernet link InOut A 1,500 byte frame takes 12  sec to serialize. Voice frame

18 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Latence avec LFI sur un lien à 56 k 189 ms total 1,500 byte data packet 10 ms 66 byte voice packet 10 ms 1,500 byte data packet 10 ms 66 byte voice packet 10 ms G.729 look ahead 20 ms packet Processing G.729 Processing Jitter buffer Serialization Network Serialization Queuing 20 ms 5 ms 10 ms 3 ms 10 ms 40 ms Queuing LFI 61 ms

19 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Matrice LFI X : Fragmentation not an issue due to bandwidth and interval combination Real-Time Packet Interval 56 Kbps 70 bytes 140 bytes 210 bytes 10 ms 20 ms 30 ms 64 Kbps 80 bytes 160 bytes 240 bytes 128 Kbps 160 bytes 320 bytes 480 bytes 256 Kbps 512 Kbps 768 Kbps 1,536 Kbps 320 bytes 640 bytes 960 bytes 640 bytes 1,280 bytes 1,920 bytes 960 bytes 1,920 bytes 2,880 bytes 1,920 bytes 3,840 bytes 5,760 bytes XX X X X X (10 ms) Example:.010 seconds x 56 Kbps 8 bits per byte = 70 bytes

20 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Gestion du délai de sérialisation Branch office 1st 1stBANK Branch office 56 Kbps Link 256 Kbps link 768 Kbps link Compress Uncompress Compress RTP UDP IP Corporation main site = 2 bytes RTP header compression: Approximately 11.2 Kbps per call Must be a link: HDLC, PPP, Frame Relay, ATM AAL-5, MPLS

21 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Délai de Queuing

22 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Connexion Admission Control Téléphone : Interdire des services, c’est mieux que de dégrader des services Data : Dégrader des services, c’est mieux que d’interdire des services Busy tone?No busy tone? Should the call be allowed to go through? CAC

23 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. RSVP ER CR ER CR ER CAC You need a 32 Kbps connection to talk with me. CAC CR = Core router ER = Edge router PATH message

24 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. RSVP Half Duplex ER CR ER CR ER Established reservation: Half the job is done.

25 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Chemin inverse ER CR ER CR ER CAC You need a 32 Kbps connection to talk with me. OK CAC (Reserve penguin) CAC

26 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. RSVP – établissement de la réservation ER CR ER CR ER Full duplex reservation

27 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. RSVP – Synchronisation QoS avant qu’un téléphone ne sonne SETUP CALL PROCEEDING PATH RESV ALERTING CONNECT RELEASE COMPLETE PATH TEAR RESV CONFIRMATION Call setup initiated OGW  TGW Reservation limited Call connected Normal call disconnect initiated OGW  TGW Reservation teardown initiated OGW  TGW Reservation initiated OGW Originating Gateway TGW Terminating Gateway OGW  TGW Reservation teardown initiated H.323 Call setup signaling RSVP reservation initiated by TGW RSVP reservation initiated by OGW

28 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Diffserv ER CR ER CR ER VPN CoS 7: Pilot CoS 6: First CoS 5: Business CoS 4: Coach CoS 3: Standby CoS 2: Baggage CoS 7 - Pilot CoS 6 - First CoS 5 - Business CoS 4 - Coach CoS 3 - Standby CoS 2 - Baggage CoS 7 - Pilot CoS 6 - First CoS 5 - Business CoS 4 - Coach CoS 3 - Standby CoS 2 - Baggage CoS 7 - Pilot CoS 6 - First CoS 5 - Business CoS 4 - Coach CoS 3 - Standby CoS 2 - Baggage CoS 7 - Pilot CoS 6 - First CoS 5 - Business CoS 4 - Coach CoS 3 - Standby CoS 2 - Baggage CoS 7 - Pilot CoS 6 - First CoS 5 - Business CoS 4 - Coach CoS 3 - Standby CoS 2 - Baggage CoS 7 - Pilot CoS 6 - First CoS 5 - Business CoS 4 - Coach CoS 3 - Standby CoS 2 - Baggage I want a first class connection. CR Check DSCP Forward packets ER Classify Mark Police

29 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Type IP du champ service IP Datagram Ethernet Version.2 header (14 octets) Entête IP (minimum length 20 octets) Entête UDP (8 octets) G.729 (20 octets) Data link trailer (4 octets) Entête RTP (12–16 octets) 20 ms Voice Contributing Source (optional) Synchronization Source Time Stamp V P X CCMPTSequence Number LengthChecksum Source PortDestination Port Options and Padding Destination Address Source Address Time to LiveProtocolHeader Checksum IdentifierFlagsFragment Offset VerIHL Type of Service Total Length Source Address (cont.)Type Source Address Destination Address (cont.) Destination Address

30 © 2005 Global Knowledge Network, Inc. All rights reserved. Contains proprietary and confidential information. Do not distribute. Champ IP TOS TOS field 2 bits 6 bits DSCP CU DSCP (DIFF-SERV code point) =DE (Default) =EF (Expedited Forwarding) DSCP (DIFF-SERV code point) =DE (Default) =EF (Expedited Forwarding) TOS field