.NET Remoting Architecture. Slide 2 CITE 4420.NET Remoting Topics Remoting Boundaries Crossing the...

.NET Remoting .NET Remoting ArchitectureArchitecture

CITE 4420 .NET Remoting Slide 2

TopicsTopics• Remoting Boundaries• Crossing the Boundaries• Distributed Applications• Marshalling• Channels• Formatters• Object Activation• Leases

• Remoting Boundaries• Crossing the Boundaries• Distributed Applications• Marshalling• Channels• Formatters• Object Activation• Leases


Remoting BoundariesRemoting Boundaries

• Windows Process Boundary

• Application Domain Boundary

• Crossing the Boundaries

• Windows Process Boundary

• Application Domain Boundary

• Crossing the Boundaries


Windows Process BoundaryWindows Process Boundary

• Every Windows application runs in a separate process

• Each process has its own virtual address space, executable code, data

• Processes are isolated from one another – cannot access address space or code of other processes

• Every Windows application runs in a separate process

• Each process has its own virtual address space, executable code, data

• Processes are isolated from one another – cannot access address space or code of other processes


Application Domain Boundary(AppDomain)

Application Domain Boundary(AppDomain)

• Created by CLR• Each AppDomain has its own code, data,

and configuration settings• AppDomain cannot directly access code or

data of another AppDomain• Code running in one AppDomain cannot

affect other AppDomains

• Created by CLR• Each AppDomain has its own code, data,

and configuration settings• AppDomain cannot directly access code or

data of another AppDomain• Code running in one AppDomain cannot

affect other AppDomains


Crossing the BoundariesCrossing the Boundaries

• .NET Remoting namespaces enable applications to cross these boundaries

• System.Runtime.Remoting– Provides an abstraction of the ISO layers– Simple mechanism for inter-application

domain communication

• .NET Remoting namespaces enable applications to cross these boundaries

• System.Runtime.Remoting– Provides an abstraction of the ISO layers– Simple mechanism for inter-application

domain communication


Crossing the Boundaries (cont’d)Crossing the Boundaries (cont’d)

• System.Web.Services– Classes that constitute the ASP.NET

Web Services framework– Use SOAP, WSDL, UDDI– Simpler to use than .NET Remoting

• System.Web.Services– Classes that constitute the ASP.NET

Web Services framework– Use SOAP, WSDL, UDDI– Simpler to use than .NET Remoting


.NET Remoting vs. Web Services.NET Remoting vs. Web Services

• Use .NET Remoting when you have control of both end-points of a distributed application

• Use Web Services when one end-point of a distributed application is not under your control

• Use .NET Remoting when you have control of both end-points of a distributed application

• Use Web Services when one end-point of a distributed application is not under your control


Distributed ApplicationsDistributed Applications

• The dominant architecture of modern applications

• Components of the application are distributed across multiple processors, accessed via a network

• The dominant architecture of modern applications

• Components of the application are distributed across multiple processors, accessed via a network


Objectives of Distributed Applications

Objectives of Distributed Applications

• Communicate between objects that run in different AppDomains and processes

• Communicate between heterogeneous architectures

• Ensure availability in spite of resource failure

• Provide increased scalability and security

• Communicate between objects that run in different AppDomains and processes

• Communicate between heterogeneous architectures

• Ensure availability in spite of resource failure

• Provide increased scalability and security


.NET Proxy Objects.NET Proxy Objects

Client object

Server object

Proxy

Remoting System

RemotingSystem


Object MarshallingObject Marshalling

• The process of gathering and formatting data about an object for transmission across a network

• Marshall-by-Reference (MBR)

• Marshall-by-Value (MBV)

• The process of gathering and formatting data about an object for transmission across a network

• Marshall-by-Reference (MBR)

• Marshall-by-Value (MBV)


ChannelsChannels

• Provide abstraction of ISO layers programming• Objects that transport messages across remoting

boundaries• Each channel has 2 end-points• Each channel is associated with a port number• .NET Framework provides HTTP and TCP

channels

• Provide abstraction of ISO layers programming• Objects that transport messages across remoting

boundaries• Each channel has 2 end-points• Each channel is associated with a port number• .NET Framework provides HTTP and TCP

channels


HTTP ChannelsHTTP Channels

• Uses the HTTP protocol• Implemented through the classes of

System.Runtime.Remoting.Channels.Http namespace

• A channel is registered with the remoting framework

• Uses the HTTP protocol• Implemented through the classes of

System.Runtime.Remoting.Channels.Http namespace

• A channel is registered with the remoting framework


TCP ChannelsTCP Channels

• Uses TCP for establishing communication between end-points

• Implemented through the classes of System.Runtime.Remoting.Channels.Tcp

• Uses TCP for establishing communication between end-points

• Implemented through the classes of System.Runtime.Remoting.Channels.Tcp


HTTP vs. TCP ChannelsHTTP vs. TCP Channels

• HTTP: highly accessible through firewalls via port 80, bulky protocol, high overhead

• TCP: limited accessibility through firewalls, very efficient packet structure, less secure

• HTTP: highly accessible through firewalls via port 80, bulky protocol, high overhead

• TCP: limited accessibility through firewalls, very efficient packet structure, less secure


FormattersFormatters

• Objects that encode and serialize data into messages before transmission over a network

• SOAP Formatter – XML-based protocol• Binary Formatter – used only within .NET

applications

• Objects that encode and serialize data into messages before transmission over a network

• SOAP Formatter – XML-based protocol• Binary Formatter – used only within .NET

applications


Channels and FormattersChannels and Formatters

• The HTTP channel uses the SOAP formatter as its default formatter for the transport of messages across a network

• The TCP channel uses the Binary Formatter as its default

• The HTTP channel uses the SOAP formatter as its default formatter for the transport of messages across a network

• The TCP channel uses the Binary Formatter as its default


Remote Object ActivationRemote Object Activation

• Activation means instantiation• Applies only to MBR objects MBV

objects are transferred to client side)• Two categories:

– Server-activated objects– Client-activated objects

• Activation means instantiation• Applies only to MBR objects MBV

objects are transferred to client side)• Two categories:

– Server-activated objects– Client-activated objects


Server-Activated ObjectsServer-Activated Objects

• Lifetime is controlled by server• Object is instantiated by a client

request for service• Two activation modes:

– SingleCall activation mode– Singleton activation mode

• Lifetime is controlled by server• Object is instantiated by a client

request for service• Two activation modes:

– SingleCall activation mode– Singleton activation mode


SingleCall Activation ModeSingleCall Activation Mode

• Object is instantiated on server for just one call from client, then destroyed

• Does not maintain state across requests

• Allows for greater server scalability

• Object is instantiated on server for just one call from client, then destroyed

• Does not maintain state across requests

• Allows for greater server scalability


When to Use SingleCall ActivationWhen to Use SingleCall Activation

• Overhead of creating object is not great• Object is not required to maintain state• Server must support large number of

requests• Object needs to be supported in a load-

balancing environment

• Overhead of creating object is not great• Object is not required to maintain state• Server must support large number of

requests• Object needs to be supported in a load-

balancing environment


Singleton Activation ModeSingleton Activation Mode

• Only one instance of object is created, regardless of number of clients using it

• Object can maintain state information across calls

• State information is shared by all clients• Lifetime is determined by leases

• Only one instance of object is created, regardless of number of clients using it

• Object can maintain state information across calls

• State information is shared by all clients• Lifetime is determined by leases


When to Use Singleton ActivationWhen to Use Singleton Activation

• Overhead of creating object is substantial

• Object is required to maintain state over a prolonged period

• Multiple clients need to work on the shared state information

• Overhead of creating object is substantial

• Object is required to maintain state over a prolonged period

• Multiple clients need to work on the shared state information


Client-Activated ObjectsClient-Activated Objects

• Server-based objects whose lifetime is controlled by the client

• Instantiated on the server when a client requests the object to be created

• Server-based objects whose lifetime is controlled by the client

• Instantiated on the server when a client requests the object to be created


When to Use Client-Activated Objects

When to Use Client-Activated Objects

• Clients want to maintain a private session with the server object

• Clients need to have control over when the objects are created and how long they live

• Clients want to maintain a private session with the server object

• Clients need to have control over when the objects are created and how long they live


Lifetime LeasesLifetime Leases• A lease defines the period of time an object

is active in memory before destruction• Represented by an object defined in the

System.Runtime.Remoting.Lifetime namespace

• Applies only to Singleton SAO’s and CAO’s

• A lease defines the period of time an object is active in memory before destruction

• Represented by an object defined in the System.Runtime.Remoting.Lifetime namespace

• Applies only to Singleton SAO’s and CAO’s


How Leases WorkHow Leases Work• A Lease Manager is created• Each time an object receives a call, the

“CurrentLeaseTime” is renewed• When a lease expires, sponsors are

contacted for renewal• When there are no renewal requests, object

is marked for Garbage Collection

• A Lease Manager is created• Each time an object receives a call, the

“CurrentLeaseTime” is renewed• When a lease expires, sponsors are

contacted for renewal• When there are no renewal requests, object

is marked for Garbage Collection

.NET Remoting Architecture. Slide 2 CITE 4420.NET Remoting Topics Remoting Boundaries Crossing the...

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