network services

Access Grid Workshop – APAC ‘05

Network Services

Susanne Lefvert [email protected] of Chicago


Outline

• Introduction• Limitations of Current Architecture• Enhanced Architecture• Network Services• Example: Debug Service• Exercises


Introduction

Network

• Enable users to seamlessly participate in AG meetings.

• Middleware

• Stream processing


Heterogeneous Environment

• Devices – VIC, RAT, Quicktime, Realplayer, H.323

clients…

• Formats– Different encodings, sample rate …

• Network – Available multicast, bandwidth …

• Preferences– Surgery: Want high resolution video– Presentation: Want lower resolution video


Class Diagram

VenueClientVenueClient

AGNodeServiceAGNodeService

AGServiceManagerAGServiceManager

AGServiceAGServiceAGServiceAGServiceAGServiceAGService

AGServiceAGService



+matches()

-role-type

Capability

Capability

• Role– CONSUMER– PRODUCER

• Type– AUDIO– VIDEO– TEXT

Not Sufficient


Sequence Diagram

Mismatch can not

be resolved


Limitations of Current Architecture

1. Service capability description limited

2. User preferences do not exist

3. No resolution to capability mismatch


Enhanced Capabilities

• Schema including:1. Service capability

• Device (sample rate, sample size, sample format…)

• Encoding (name, quality, bit rate, size…)• RTP (payload type, profile…)

2. Node capability• Available bandwidth, multicast, firewall…

3. User preferences• Preferred quality, bandwidth…


VenueClientVenueClient

AGNodeServiceAGNodeService


AGServiceAGServiceAGServiceAGServiceAGServiceAGService

AGServiceAGService


CapabilityCapability

Service Capability

Node Capability

User Preferences


Sequence Diagram

NetworkServiceVenue NetworServicesManagerVenueClient

Enter

CapabilityMismatch

Matcher

FindServices(StreamDescription, myCapability)

[StreamDescription]

Transform(StreamDescription)

NegotiateCapabilities()

[NetworkServiceDescription]

Match(StreamDescription, myCapability, [NetworkServiceDescription])

[NetworkServiceDescription]

[StreamDescription]


Network Service

y = Transform(x)x y

x y


Matcher

Venue

Stream Capabilities

Node Capabilities

Mismatch

1.

Network Service

Node Capabilities

Stream Capabilities

MatchMatch

2.


Network Service

• Registers with a venue or a venue server

• Includes input and output capabilities

• Provides a Transform() method

• Has an interface for remote configuration

• Emits heartbeats


Example: Video Selector

GOAL: Reduce bandwidth

EXAMPLE: Connect from home


Multicast

Multicast

VideoSelector

Example: Video Selector


Example: Transcoder

GOAL: Enable more devices

EXAMPLE: H.323 client


Multicast

AudioTranscoder

Multicast

Linear16 pcmu

Example: Transcoder


Implementation Details

1. Add new capabilities (ServiceCapability) to your node services.

2. Create a network service matching the new capabilities of the node services.

3. Connect the network service to the venue

4. Connect your node services to the venue


Network Service Base Class

• Initiates the AG environment

• Hides SOAP details

• Includes logging

• Communicates with venues

• Includes the Transform() method


Service Capabilities

• Describe input and output

• Same as node service capabilities

• Used during capability negotiation and network service matching


Example: Video Selectorclass SelectorNetworkService(AGNetworkService): def __init__(self, name): AGNetworkService.__init__(self, name, 'Selector', '1.0')

# Create capabilities inconfig = {"Encoding":"H261"} inCap = ServiceCapability(name, 'consumer', 'video', inconfig)

outconfig = {"Encoding":"H261", "StreamSelection":"On"} outCap = ServiceCapability(name, 'producer', 'video', outconfig) self.inCapabilities = [inCap.ToXML()] self.outCapabilities = [outCap.ToXML()]

# Manage processes self.processManager = ProcessManager()

# Start the soap interface self.Start(self)

def StopTransform(self, streamList): # Stop video selector self.processManager.TerminateAllProcesses()


Example: Video Selectordef Transform(self, streamList): # Start video selector newStreams = []

for s in streamList: cap = s.capability cap.xml = self.outCapabilities[0]

# Create new stream description location = MulticastNetworkLocation("224.2.2.2", 8000) ns = StreamDescription("Video Selector Stream", location, cap) newStreams.append(ns)

# Create process arguments fromaddr = s.location.host fromport = s.location.port toaddr = ns.location.host toport = ns.location.port executable = os.path.join(os.getcwd(), "Selector.py") options = [executable, fromaddr, fromport, toaddr, toport, 1]

# Start process self.processManager.StartProcess(sys.executable, options)

return newStreams


Example: Video Selector Consumer Service

def __SetCapabilities(self): oldCap1 = Capability( Capability.CONSUMER, "video" ) # Create new capabilities to include in old capability format val = "Off" for c in self.configuration: if c.name == "video selection": val = c.value config = {"StreamSelection": val, "Encoding":"H261"}

nsc1 = ServiceCapability('Video Consumer Selector', oldCap1.role, oldCap1.type, config) oldCap1.xml = nsc1.ToXML() self.capabilities = [oldCap1]


Exercises

Exercise 6 – Network Services:

• Testing the video selector service

• Running a debug network service

• Creating a custom SOAP interface for configuration

• Creating a client for connecting to the custom SOAP interface

http://www.mcs.anl.gov/fl/research/accessgrid/documentation/tutorial/AGTk_2.4


Exercises 1: Video Selector

1. Install the modified node services with new capabilities.

2. Enter the venue the video selector is connected to

3. Switch between video selection on and off


Exercises 2: Debug Service

1. Install the two modified node serviceswith new service capabilities

2. Modify the Debug Network Service

3. Connect the network service to a venue and enter with the two node services to trigger matching.


Exercises 3: SOAP Interface

1. Add a SOAP interface to the debug service

2. Create a client that can communicate remotely with the debug network service SOAP interface.

network services

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