1. Internet Quality of Service

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

3. 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

4. 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

5. 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

6. 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)

7. 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

8. 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

9. 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

10. 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

11. 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

12. Label Creation & Signaling
[iec.org]

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

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

15. 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 n/b/g/a (**)
Network systems experience, some programming
Comparing different technologies

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