Enhanced General Switch Management Protocol

1. Enhanced General Switch Management Protocol Salim Hariri Department of Electrical and Computer Engineering HPDC Laboratory The University of Arizona ECE Building, Room 421 Tucson, Arizona, AZ 85750 Tel: (520) 621-4378, Fax: (520) 621-8076 hariri@ece.arizona.edu, www.ece.arizona.edu/~hpdc

2. Why Programmable Networks? • Rapid creation, deployment and management of new services in response to user demands. • Change in the nature of traffic due to the wide variety of applications and services. • Application specific demands for resources. • Need for the separation of communication hardware from control software. • Better control over the network resources for its effective use.

3. Classification of Programmable Networks Programmable Networks Active Networks (Dynamic Approach) Open Interface Networks (Static Approach) Integrated Approach (In band) ATM IP Discrete Approach (Out of Band) e-GSMP P 1520 Model q-GSMP GSMP

4. Open Interface Networks • Provides abstractions in the layers of a node to define programmable interfaces. • Allows applications and middle-ware to manipulate low-level network resources. • Uses APIs to control the various layers.

5. Open Interface Networks (Contd.) • Advantages: • Separation of service business. • Separation of vendor business. • Faster standardization. • Extensibility • Richer Semantics

6. Meaning of QoS • Quality of Service (QoS) refers to the capability of the network to provide better service to selected network traffic irrespective of the underlying technologies. • The goal of QoS is to provide priority including dedicated bandwidth, controlled jitter and latency and improved loss characteristics.

7. QoS in OSI Model

8. QoS over ATM • Providing QoS overATM is easier • Fixed length of cells • Well defined types of services. • Techniques for providing QoS in ATM • General Switch Management Protocol (GSMP) • q-GSMP

9. General Switch Management Protocol(RFC 1987) • Open Interface, switch control protocol. • Connection oriented network technologies. • Point-point and Multi-point connections. • Adjacency protocol -synchronize state across link. • Master-Slave relationship between controller and the switches

10. GSMP VPC/VCCs Policer Classifier Regulator Scheduler Confirming QoS Class Excess Output Port Confirming QoS Class Excess

11. GSMP Message Sequence Connection Management Switch controller Switch Mapping Port Management Configuration Information Statistics Network Events qGSMP ATM Switch

12. q-GSMP • Provides QoS extensions to the GSMP. • Supports new messages enabling selection of: • QoS constraints • Buffer management • Scheduling algorithms • Memory allocation schemes. • Specific to ATM switches.

13. q-GSMP Connection Management Switch Mapping Port Management Configuration Information Statistics Network Switch Controller Scheduler Scheduler Events QoS Management Buffer Manager QoS Configuration Management QoS Statistics SR Estimator QoS Events qGSMP ATM Switch

14. QoS over IP Issues: • IP was not meant to provide better than the best effort QoS. • Complex scheduling and buffer management due to variable length packets. • Changes in the traffic pattern at the output of a router due to traffic aggregation.

15. Need for IP QoS • Traditional IP networks support only best effort delivery. • Convergence of voice and data requires IP network to provide deterministic guarantees for real time traffic. • Multimedia traffic require both bandwidth and delay guarantees.

16. P-1520 Model • Defines a set of Programmable interfaces for the development of the protocol and management of the infrastructure. • Defines four interfaces: • Value Added Service Level • Network Generic Services Level • Virtual Network Device Level • Physical Elements Level

17. P-1520 Model V Interface Algorithms for value added communications Value Added Services Level U Interface Algorithms for routing and connection management Network Generic Services Level L Interface Virtual Network Device Virtual Network Devices Level CCM Interface Physical Elements (Hardware) PE Level

18. IP reference Model

19. Features of our IP Model • Extension of Integrated Services Model of Clark,Shenker and Zhang[ ]. • Conforms to P1520 model[ ] of programmability. • Complies with ForCES architecture[ ] of network entity. • Incorporates ETRI’s Router Architecture.

20. ETRI’s Router Architecture

21. Scheduler and Queues Scheduler Outbound Packets Packets in Various Queues

22. Algorithm for Schedulability We consider the Diffserv QoS, classes of service. Let us assume that DS(i) = ith class of service. Vector Q(i) = [ q1(i) q2(i),…….qm(I)] be the QoS Parameters for the ith class. We define a matrix Qm consisting of all the QoS classes and their respective parameters. Q(1) q1(1) q2(1) ………qm(1) Qm = Q(2) = q1(2) q2(2) ………qm(2) Q(n) q1(n) q2(n) ………qm(n)

23. 01 02 n-1 n Scheduler Input of a Router Media I/F Packet Classification Inbound Packets Switch/ Backplane Per-dest Queues Bandwidth/Delay Shaped Queues

24. A table K is maintained by the router to indicate the number of packets in each QoS class. K = [k1,k2…………kn] Bo = port bandwidth B = total bandwidth. Bo = Σ ki * q1(i) if (q1(i) <= (B-Bo)) then BandSchedulable =TRUE; else BandSchedulable = FALSE;

25. Output from a Router Media I/F Outbound Packets Scheduler Packet Processor Switch/ Backplane Bandwidth/Delay Shaped Queues

26. Admission Control Algorithm The Admission control is made at the line cards. Token Bucket algorithm is used to characterize the flows. A new flow is admitted if the following condition is satisfied PBRnew + NΣ i=1 PBRi <= ρC where PBR = peak bit rate ρ = admissible load of capacity C = total capacity

27. e-GSMP • Envisages to provide QoS services over a primarily IP network. • Is an Open Interface approach. • Defines a Master-Slave relationship between the Controller and the IP Routers. • Allows an interactive approach to provide programmability.

28. e-GSMP Schedulable Region Estimators Switch Mapping 1 Multiplexer Multiplexer m Multiplexer Input Ports Output Ports Switch Fabric

29. e-GSMP • To support the Intserv and Diffserv frameworks. • To define schedulable regions to implement admission control. • To allow for different scheduling and buffer management techniques.

30. Concluding Remarks