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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 - PowerPoint PPT Presentation
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Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
Enhanced General Switch Management Enhanced General Switch Management ProtocolProtocol
Salim HaririDepartment of Electrical and Computer Engineering
HPDC Laboratory
The University of Arizona
ECE Building, Room 421Tucson, Arizona, AZ 85750
Tel: (520) 621-4378, Fax: (520) 621-8076
[email protected], www.ece.arizona.edu/~hpdc
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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.
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
Classification of Programmable Networks
Programmable Networks
IPATM
Active Networks(Dynamic Approach)
q-GSMPGSMP e-GSMPP 1520 Model
Discrete Approach
(Out of Band)
Integrated Approach(In band)
Open Interface Networks(Static Approach)
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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.
Open Interface Networks
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
Open Interface Networks (Contd.)
Advantages:– Separation of service business.– Separation of vendor business.– Faster standardization.– Extensibility– Richer Semantics
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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.
Meaning of QoS
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
QoS in OSI Model
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
Providing QoS over ATM is easier– Fixed length of cells– Well defined types of services.
Techniques for providing QoS in ATM– General Switch Management Protocol (GSMP)– q-GSMP
QoS over ATM
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
GSMPClassifier Regulator SchedulerVPC/VCCs
Policer
Output Port
Confirming
Confirming
Excess
Excess
QoS Class
QoS Class
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
GSMP Message Sequence
Switch controller Network
Switch Mapping
Connection Management
Port ManagementConfiguration Information
StatisticsEvents
qGSMP ATM Switch
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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.
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
q-GSMP
Switch Controller
SchedulerScheduler
Network
Switch Mapping
Buffer Manager
SR Estimator
qGSMP ATM Switch
Connection Management
Port Management
Configuration Information
StatisticsEvents
QoS Management
QoS Configuration Management
QoS Statistics
QoS Events
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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.
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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.
Need for IP QoS
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
P-1520 Model
Algorithms for value added communications
Algorithms for routing and connection management
Virtual Network Device
Physical Elements (Hardware)
V Interface
U Interface
L Interface
CCM Interface
Value Added Services Level
Network Generic Services Level
Virtual Network Devices Level
PE Level
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
IP reference Model
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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.
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
ETRI’s Router Architecture
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
Scheduler and Queues
Outbound Packets
Scheduler
Packets inVarious Queues
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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)
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
Packet
Classification
Switch/Backplane
Media
I/F
01
02
n-1
n
Input of a Router
Bandwidth/Delay Shaped Queues
Per-destQueues
Scheduler
InboundPackets
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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;
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
Packet
Processor
Switch/Backplane
Output from a Router
Bandwidth/DelayShaped Queues
Scheduler
Media
I/F
OutboundPackets
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
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.
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
e-GSMP
Switch FabricInput Ports Output Ports
Multiplexer
Multiplexer
Multiplexer
1
m
Switch Mapping Schedulable Region Estimators
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
To support the Intserv and Diffserv frameworks. To define schedulable regions to implement
admission control. To allow for different scheduling and buffer
management techniques.
e-GSMP
Salim Hariri HPDC Laboratory http://www.ece.arizona.edu/~hpdc
Concluding Remarks