Internet Quality of Service

Puzzle You have an unfair coin (prob(H) = p != ½) How will you generate a fair toss?

Recap Intserv Diffserv Core-stateless Per-flow QoS Per-flow state/processing – not scalable Diffserv Coarse QoS No per-flow state/processing at all routers Core-stateless Scalable network model Per-flow QoS achieved

MPLS CoS (class of service) mechanism for the Internet Addresses speed, scalability, QoS (quality of service), and traffic engineering IETF defined framework that provides for efficient designation, routing, forwarding, and switching of traffic flows

MPLS – key functions mechanisms to manage traffic flows of various granularities – machines, flows, AS independent of layer 2 and layer 3 protocols means to map IP addresses to simple fixed length labels interfaces to existing protocols like RSVP and OSPF supports IP, ATM, and frame-relay

MPLS LSPs LSP – label switched path In MPLS, data transmission occurs on label switched paths LSP – a sequence of labels at each and every node along the path from the source to the destination LSPs established either before data transmission begins (control-driven) or upon detection of data (data-driven)

MPLS LSPs (contd.) Labels are distributed using LDP (label distribution protocol) Each data packet in an MPLS network carries a label High speed switching of data becomes possible as hardware can switch based on labels

Routers in MPLS LERs – label edge routers Operates at the edge of the network Responsible for establishing LSPs Adds/removes labels as traffic enters/leaves network LSRs – label switching routers High speed core router device Participates in establishing LSPs High speed switching of data using labels

Forward Equivalence Class (FEC) Class of packets that share same transport requirements All packets in a class treated the same Each LSR maintains a label information base (LIB) LIB comprises of FEC-to-label bindings

Labels A label identifies the path a packet should traverse within an MPLS network The label is typically carried in the layer 2 header or in a layer 2.5 header Label values have local significance only FR DLCIs (data link channel identifiers) or ATM VPIs/VCIs can be used as labels directly

Label Bindings Labels are bound to FECs based on some policy like destination unicast routing traffic engineering (RSVP-TE, CR-LDP) multicast virtual private network (VPN) QoS

Label Creation & Signaling [iec.org]

Projects 4 projects 2 teams (2 students each)/project Send email to Sriram on your top 2 choices before 11.59pm tomorrow (Friday) I will resolve conflicts after discussions with students

Timeline Projects chosen: September 22nd Synopsis: September 28th

List of Projects (Testbeds) ns2 (****) C & Network programming, networked apps New transport layer research problem PlanetLab (****)^ C & Network programming, kernel programming Split flow networking vs. Confluent flow networking Sensor Network Test-bed (***) C programming, network systems experience Real time sensor networks Wireless VoIP (***) C/Java programming, Network programming Improving call capacity of wireless VoIP Heterogeneous WiFi 802.11n/b/g/a (**) Network systems experience, some programming Comparing different technologies

Puzzle How can a toss be called over the phone (without requiring trust)?