Network layer Doug Young Suh Last update : Aug. 1, 2009 Network Layer

Network layer and realtime multimedia Protocols for switching in the routers Routing = path + resource cf) direction + width of road IP header : IPv4 and IPv6 New features in IPv6 Best Effort  per-class  per-flow intServ. diffServ, MPLS MediaLab, Kyunghee University2

Networked Video QoS control for networked video Physical Layer Data Link Layer Network Layer Transport Layer Upper Layers (Video Layer) End- to- end Error resilience/concealment, scalability coding UDP/RTP&RTCP, FEC, retransmission IP TOS, RSVP, intServ FEC, retransmission, MAC Power control

Networked Video Network layer approaches RSVP intServ diffServ MPLS Transport Layer  Over-provision or QoS control?  Internet service will be charged.  IPv6 doesn't give a solution for the QoS issue. IPv6 has the potential. Video Layer

Categories of QoS protocols Circuit switching or broadcasting Fixed QoS Dedicated circuit for a call e.g. telephone Network QoS Packet switching Variable QoS (Best Effort) Resource sharing e.g. downloading data QoS switching Guarantee reserved QoS Resource allocation (dynamic) e.g. realtime service QoS switching 1.Per-class (coarse) : Packets are classified into several classes. 2.Per-flow (fine) : A flow could be a media stream of a certain service. Call admission control is required for resource reservation with all routers along the path.

Per-class and per flow QoS services I’m a class B packet. You, use the Gate B. I’m a video packet for the video-phone service between John and Susan. We provide you QoS of [5Mbps, packet loss, and 1ms delay]. After reading the temporary customer list for identification,,,,,,, Per-class QoS service Per-flow QoS service router

QoS identification for every video packet per-class QoS : 8 bit TOS (TC) in the IP header BA (behavior aggregate) classifier PHB : EF and AF(4 classes with 3 levels) per-flow QoS Each flow has a temporary contract on QoS. IntServ : identified by 5 tuples 104 bits IPv4, 296 bits IPv6 MPLS : identified by label SADASPDPPrdata Admission control Packet scheduler classifier data SADASPDPPr TSpec1 SADASPDPPr TSpec2 SADASPDPPr TSpec3 SADASPDPPr TSpec4 SADASPDPPr TSpec5 intServ routing table label BA classifier PHB1 PHB2 PHB3

RSVP/intServ CAC by RSVP, call control by intServ

Networked Video RSVP parameters Tspec (PATH), Rspec (RESV) r : token rate b : token-bucket depth p : peak rate m : minimum policed size M : maximum packet size Leaky bucket model [r,b], [p,M]

Networked Video Resource reservation When realtime service needs excess bandwidth, non-realtime service packets are buffered.

Networked Video Diffserv Architecture Edge router: - per-flow service - marks packets of in- or out-profile Core router: - per class service - buffering and scheduling - preference to in-profile packets - Assured Forwarding CR scheduling... r b ER marking Bandwidth Broker

Networked Video ER : Traffic Conditioning Classifier of micro-flow w.r.t. agreed traffic profile Marker : low, medium, high drop precedence

Networked Video CR : traffic management BA (behavior aggregate) classifier PHB EF : guaranteed service, WFQ (weighted fair queuing) AF : 4 classes with 3 levels (high, medium, low drop procedure levels), RED (random early discard) BA classifier PHB1 PHB2 PHB3

History of video/network Packet switching : Best effort per class QoS Per flow QoS ~AVC SV C ?? Circuit switching Broadcasting H.261 MPEG-2 IPv42GIPv63-4G MPEG-4 & AVC 2008 No QoS control, because everything is fixed. No QoS control, because network does not care. Coarse QoS control, [premium, medium, low, etc.] Fine QoS control, each media traffic of each individual service

Revisit QoS of upper layers. Video layer Feedback rate control Realtime encoding : quality vs. bitrate (R-D) Non-realtime encoding : Scalable coding VBR(natural) and CBR(forced rate control) Multiple levels of significance Partition A, B, C in a frame Intra > predictive > bi-directional Scalable coding : base layer > enhancement layers Error propagation and error resilience Transport layer Feedback of QoS metrics : loss/delay/bitrate FEC : UEP/ULP (unequal error/loss protection) MediaLab, Kyunghee University15

Networked Video IPv6 (IPng) 128 bit address => 18  nodes, 4 nodes/cm 2 Ubiquitous networks Hierarchical addresses multicast, anycast => QoS aware broadcasting Simplified header (for realtime sevice) Improved security Auto-configuration plug-play network access (DHCP, ND) micro-mobility QoS awareness traffic class (8 bits) flow label (20 bits, cf. VC of ATM)

Networked Video Header formats of IPv4/IPv6 Version (4) Traffic Class (8) Flow Label (20) Payload Length (16) Next Header (8) Hop Limit (8) Source Address (128) Destination Address (128) Version (4) HLEN (4) Type of Service (8) Total Length (16) Identification (16) Flags (3) Fragment Offset (3) TTL (8)Protocol (8) Header Checksum (16) Source IP Address (32) Destination IP Address (32)

Networked Video IPv6 is reality. Worldwide IPv6 network : tunneling-based IPv6 routers : 3Com, Compaq, Ericsson Telebit, Hitachi Ltd., Nokia Telecom, Northern Telecom, IPv6 Linux kernel Windows NT, Windows 2000 Future : wireless services in China, ubiquitous network

Multicast in IPv6 T : permanent (0) or transient (1) Scope : geographic scope (within node~global) TScopeMulticast group address

Networked Video Anycast in IPv6 010Reg.TLANLASLAInterface ID  TLA, NLA, SLA : aggregators  Anycast : A group of hosts or routers can have the same address and provide the same service. Clients are connected to the nearest server. (cf: local broadcasting stations) anyTV.co.kr

Networked Video MIPv6 multimedia service

IntServ/RSVP Network Layer

QoS Support in the Internet Call admission control (CAC)  traffic policing by using signaling protocol Traffic characteristics and requirements Traffic shaping : User’s effort to keep promise Traffic policing : Router’s effort to police Network Layer CAC Traffic shaping Traffic policing

Scheduling (queuing) algorithms FIFO (First In First Out) Weighted fair queuing (WFQ) Deficit round robin (DRR) Stochastic fair queuing (SFQ) Round robin (RR) Strict priority Network Layer

ReSource reserVation Protocol (RSVP) Previously, RFC1819 Internet Stream Protocol v2 (ST2+) referred as “IPv5” RFC 2205 RSVP (1997) RSVP and intServ : RFC 2210 Signaling to reserve resource along the path of particular data streams or flows Unicast and multicast Multipoint to multipoint Multipoint to single point Network Layer HostRouter Host PATH RESV

“PATH” and “RESV” Messages “PATH” : from source to target Marks the routed path and collects information about the QoS viability of each router along the path “RESV” : from target to source It the target wants, reserves resources along the path Routers can “merge” downstream reservations to the same stream. State is maintained as long as “PATH” and “RESV” messages flow. Receiver driven (compared to broadcasting) Large group, dynamic group membership, heterogeneous receiver requirements “dynamic”=soft state : created/modified/removed Network Layer

RSVP What I am originating application and sub-flow such as print flow vs. time-critical transaction Who I am authenticated user ID What I want the type of QoS service needed How much I want certain applications quantify their resource requirements precisely. How I can be recognized the 5-tuple classification criteria by which the data traffic can be recognized Which network devices resources will be impacted by the associated data traffic Network Layer

RSVP modules in hosts and routers Application  RSVP process Admission control : sufficient available resources for the request? Policy control : whether the use has permission for the reservation? Network Layer Appli- cation RSVP process Policy control Admission control Packet scheduler classifier data Routing process RSVP process Policy control Admission control Packet scheduler classifier data HostRouter intServ control RSVP

Reservation Request Spec.s Filter spec. (logical) Selection of subsets of the packets of a given session Sender IP address and source port To set parameters in the packet classifier Flow spec. (quantitative) Specification a desired QoS Service class Tspec (traffic descriptor) Rspec (desired QoS parameters) To set parameters in the node’s packet scheduler Network Layer

RSVP parameters Tspec (PATH), Rspec (RESV) r : token rate b : token-bucket depth p : peak rate m : minimum policed size M : maximum packet size Double leaky bucket model [r,b], [p,M] Network Layer r <b <M p VBR : average rate < r < p CBR : average rate = r = p

Tspec/Rspec in RFC2210 Network Layer Guaranteed service Controlled load

RSVP Styles Fixed-filter All sender are active at all time. S1S2 N R f f 2f S1S2 N R f f f  One sender at a time  Wildcard-filter  e.g. audio conferencing  Shared explicit  The receiver select a sender. sender filter receiver router

Scalability Problem 3 step processes for every intServ packet 1. Identification of an intServ packet by 5 tuple classifiers { (SA, DA), (source port #, receiver port #), protocol } 2. Searching for the service spec. for the packet 3. Traffic policing and scheduling Impossible inside core network Maybe possible in edge routers of mobile network Network Layer SADASPDPPrdata Admission control Packet scheduler classifier data SADASPDPPr TSpec1 SADASPDPPr TSpec2 SADASPDPPr TSpec3 SADASPDPPr TSpec4 SADASPDPPr TSpec5 intServ routing table

5-tuples in IPv4 and IPv6 Network Layer  Flow ID : 104 bits in IPv4 and 296 bits in IPv6  IPv4 104 = 32*2 (SA, DA) + 32(SP, DP) + 8 (protocol)  Scalability problem in public network ~N N  Class ID : 6 bits in DS field  diffServ

Networked Video MPLS (Multi-Protocol Label Switching) Scalability problem of intServ A set of 5 tuples  a temporary label Virtual switch for the efficiency of routers (cf. ATM) Connection oriented : VC (Virtual Circuit) VC lookup table (resource, path) Routing flexibility Traffic engineering and provisioning Constraint-based routing (QoS routing) FEC (Forward Equivalence Class) With RSVP  IPv6 “Flow Label”

Conclusions intServ for per-flow service  IEEE801.16, UMTS~ RSVP for resource reservation Controlled load, guaranteed service CAC  traffic shaping / policing Scalability problem MPLS, IPv6 flow label for simplified identification Advanced approach RFC4495 “RSVP Extension for Reduction of Bandwidth” (2006) Draft-intserv-multiple-tspec (2010) “…. to dynamically adapt to available bandwidth…” Multiple reservations between two endpoints Refreshes only include the Tspecs that were accepted MediaLab, Kyunghee University36