What is the relationship between components of vc

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what is the relationship between components of vc

between components, in terms of a relation between a variable cluster in a domain component In CONFIG, the function of a relation is elaborated, using VCs. Answer to What is the relationship between the components of TLC? What is the relationship between the components of vc? 1. An important element for a succesful VC firm is a culture that encourages in how the VC firm will invest and interact with the startup and technology ecosystem a monkey wrench into the relationship with founders and most often the VCs.

Reusability COM supports black-box reusability, which means that the implementation details of a reusable component are not exposed to clients. To achieve black-box reusability, COM supports two mechanisms through which one object may reuse another.

The two forms of reuse are named containment and aggregation. By convention, the object being reused is named the inner object, and the object that is making use of the inner object is named the outer object.

In containment, the outer object behaves as a client of the inner object. The outer object is a logical container for the inner object, and when the outer object uses the services of the inner object, the outer object delegates implementation to the inner object's interfaces. This means that the outer object is implemented in terms of the inner object's services. The outer object may not support the same interfaces as the inner object, and the outer object may use an inner object's interface to help with implementing parts of a different interface on the outer object.

In aggregation, the outer object exposes interfaces from the inner object as if they were implemented on the outer object. This is useful when the outer object would always delegate every call on one of its interfaces to the same interface of the inner object. Aggregation is a convenience that enables the outer object to avoid extra implementation overhead. For more information, see Reusing Objects. Storage and Stream Objects COM objects save state to a file by using structured storage, which is a form of persistent storage that enables navigation of a file's contents by using file system semantics.

COM Technical Overview - Windows applications | Microsoft Docs

Treating a file's contents in this manner enables features such as incremental access, transactions, and sharing among processes. The COM persistent storage specification provides for two types of storage elements: These objects are implemented by the COM Library, and user applications rarely implement these storage elements.

Storage objects implement the IStorage interface, and stream objects implement the IStream interface. A stream object contains data and is conceptually similar to a single file in a file system. Each stream has access rights and a single seek pointer. Through the IStream interface, you can read, write, seek, and perform other operations on the stream's underlying data. A stream is named by using a text string.

It can contain any internal structure, because it is a flat stream of bytes. In addition, the functions in the IStream interface are similar to standard file-handle based functions, such as those in the ANSI C run-time library.

A storage object is conceptually similar to a directory in a file system. Each storage can contain any number of sub-storage objects and any number of streams. Each storage has its own access rights. Through the IStorage interface, you can perform operations such as enumerating, moving, copying, renaming, creating, and deleting elements. A storage object does not store application-defined data, but it stores implicitly the names of the elements storages and streams that it contains.

Storage and stream objects are sharable among processes when they are implemented according to the COM specification on a host platform. This enables objects that are running in-process or out-of-process to have equal incremental access to their file storage.

Because COM is loaded into each process separately, it uses operating-system supported shared memory mechanisms to communicate the state of opened elements and their access modes between processes. Every storage and stream object in a structured file has a name to identify it. The name is a string that follows a particular convention. For more information, see Storage Object Naming Conventions. The name is passed to IStorage functions to specify which element in the storage to operate on.

Names of root storage objects are the same as file names in the underlying file system, and these names must follow the file system's conventions and restrictions. Strings passed to storage-related functions which name files are passed through to the file system without interpretation or changes.

Names of elements that are contained within storage objects are managed by the implementation of the particular storage object in question. All implementations of storage objects must support element names that are 32 characters in length, and some implementations may support longer names.

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Names are stored with case preserved, but they are compared as case-insensitive. Applications that define storage element names must choose names that work in either situation. You access every element in a structured storage file by using functions and interfaces that are implemented by COM. This means that other applications can browse the file by navigating with the IStorage interface functions that provide directory-like services.

Also, other applications can use the file's data, without having to run the application that wrote the file. When a COM application accesses the structured storage files of another application, standard Windows access rights apply, and the application must have sufficient privileges.

A COM object can read and write itself to persistent storage. A client queries for one of the persistence-related interfaces on the COM object, depending on the context of the operation.

Understanding Virtual Chassis Components - TechLibrary - Juniper Networks

COM objects can implement any combination of the following interfaces: The COM object reads and writes its persistent state to a storage object. The client provides the object with an IStorage pointer through this interface. This is the only persistence interface that includes semantics for incremental access. The COM object reads and writes its persistent state to a stream object. The client provides the object with an IStream pointer through this interface.

The COM object reads and writes its persistent state directly to a file on the underlying system. This interface does not involve IStorage or IStream unless the underlying file is accessed through these interfaces, but the IPersistFile interface has no semantics for storages and streams. The client provides the object with a file name and calls the Save or Load functions.

Data Transfer Structured storage provides the basis for data exchange between COM objects and processes, which is named uniform data transfer. Before COM was implemented in OLE 2, data transfer on Windows was specified by transfer protocols, such as the clipboard and drag-drop protocols.

Each transfer protocol had its own set of functions that bound the protocol to the query, and specific code was required to handle each different protocol and exchange procedure.

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Uniform data transfer represents all data transfers by using the IDataObject interface, which separates common data exchange operations from the transfer protocol.

The IDataObject interface encapsulates the standard get and set operations on data, queries and enumerations, and notifications that detect when data changes in an object.

Uniform data transfer enables rich descriptions of data formats, as well as the use of different storage media for the data transfer. During uniform data transfer, all protocols exchange a pointer to an IDataObject interface. The server is the source of the data and implements one data object, which is usable in any data exchange protocol. The client consumes the data and requests data from a data object when it receives an IDataObject pointer from any protocol.

After the pointer exchange has occurred, both sides handle data exchange in a uniform fashion, through the IDataObject interface. COM defines two data structures that enable uniform data transfer. The client creates a FORMATETC structure to indicate the type of data that it requests from a data source, and it is used by the data source to describe what formats it provides.

For example, if the data to be exchanged is very large, the data source can indicate a disk-based medium as its preferred format, instead of main memory. This flexibility enables efficient data exchanges that can be as fast as passing a pointer to an IStorage or an IStream. A client of a data source may require notification when the data changes.

COM handles data-change notifications by using an advise sink object, which implements the IAdviseSink interface. The advise sink object and the IAdviseSink interface are implemented by the client, which passes an IAdviseSink pointer to the data source. When the data source detects a change in the underlying data, it calls an IAdviseSink method to notify the client. For more information, see Data Notification. Remoting COM enables remote and distributed computation. Interface remoting enables a member function to return an interface pointer to a COM object that is in a different process or on a different host computer.

The infrastructure that performs the interface remoting is transparent to both the client and the object server. Neither the client nor the server need one another's deployment details to communicate through a remoted interface.

A client calls member functions on the same interface to communicate with a COM object that is in-process, out-of-process on the local host, or on a remote computer. Local and remote calls on the same interface are indistinguishable to the client. To communicate with a COM object, a client always calls an in-process implementation. If the COM object is in-process, the call is direct.

A COM object always receives calls from a client through an in-process implementation. If the caller is in-process, the call is direct.

If the caller is out-of-process or remote, COM provides a stub implementation that receives the remote procedure call from the proxy in the client process. Marshaling is the procedure for packaging the call stack for transmission from proxy to stub.

Unmarshaling is the unpackaging that occurs at the receiving end. Return values are marshaled and unmarshaled from the stub to the proxy. This kind of communication is also referred to as sending a call over the wire. Each different data type has rules for marshaling. Interface pointers also have a marshaling protocol, which is encapsulated in the CoMarshalInterface function.

In most cases, standard interface marshaling, which is provided by the system, is sufficient, but a COM object optionally may implement custom interface marshaling to control the creation of remote object proxies to itself.

Maintains a state of readiness to take over the master Routing Engine role if the master fails. Synchronizes with the master in terms of protocol states, forwarding tables, and other information, so that it is prepared to preserve routing information and maintain network connectivity without disruption in case the master is unavailable.

You must have at least two member switches in the Virtual Chassis configuration in order to have a backup Routing Engine member. In a preprovisioned configuration, one of the two members assigned as routing-engine functions in the backup role. A mixed EX and EX Virtual Chassis must use an EX member switch in the master role, and configuring an EX switch into the backup role ensures that the Virtual Chassis remains up after a switchover event.

Linecard Role A member that functions in the linecard role in a Virtual Chassis: Runs only a subset of Junos OS. Does not run the chassis control protocols. Can detect certain error conditions such as an unplugged cable on any interfaces that have been configured on it through the master.

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The Virtual Chassis configuration must have at least three members in order to include a linecard member. In a preprovisioned configuration, you can explicitly configure a member with the linecard role, which makes it ineligible for functioning as a master or backup Routing Engine.

In a configuration that is not preprovisioned, the members that are not selected as master or backup function as linecard members of the Virtual Chassis configuration. The selection of the master and backup is determined by the mastership priority value and secondary factors in the master election algorithm.

A switch with a mastership priority of 0 is always in the linecard role. Any switch can function in the linecard role in a mixed or non-mixed Virtual Chassis.

what is the relationship between components of vc

When one of those switches is powered on, it receives a member ID that can be seen by viewing the front-panel LCD or by entering the show virtual-chassis command. When the switch is interconnected with other switches in a Virtual Chassis configuration, its member ID is assigned by the master based on various factors, such as the order in which the switch was added to the Virtual Chassis configuration or the member ID assigned by a preprovisioned configuration. If the Virtual Chassis configuration previously included a member switch and that member was physically disconnected or removed from the Virtual Chassis configuration, its member ID is not available for assignment as part of the standard sequential assignment by the master.

For example, you might have a Virtual Chassis configuration composed of member 0, member 2, and member 3, because member 1 was removed. When you add another member switch and power it on, the master assigns it as member 4. The member ID distinguishes the member switches from one another. You use the member ID: To assign a mastership priority value to a member switch To configure interfaces for a member switch The function is similar to that of a slot number on Juniper Networks routers.

To apply some operational commands to a member switch To display status or characteristics of a member switch Mastership Priority In a configuration that is not preprovisioned, you can designate the role master or backup Routing Engine role, or linecard role that a member switch assumes by configuring its mastership priority from 0 through The mastership priority value is the factor in the master election algorithm with the highest precedence for selecting the master of the Virtual Chassis configuration.

A switch with a mastership priority of 0 never assumes the backup or master Routing Engine role. The default value for mastership priority is When a standalone switch is powered on, it receives the default mastership priority value. Because it is the only member of the Virtual Chassis configuration, it is also the master. When you interconnect a standalone switch to an existing Virtual Chassis configuration which implicitly includes its own masterwe recommend that you explicitly configure the mastership priority of the members that you want to function as the master and backup.

Note Configuring the same mastership priority value for both the master and backup helps to ensure a smooth transition from master to backup when the master becomes unavailable. It prevents the original master from preempting control from the backup when the backup has taken control of the Virtual Chassis configuration because the original master became unavailable.

what is the relationship between components of vc