GP.Access Distribution - Revision history

Jan Schoonderbeek: added queuing

2015-01-02T15:40:07Z

added queuing

← Older revision		Revision as of 15:40, 2 January 2015
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	\|name=Access Distribution		\|name=Access Distribution
	\|sector=Business Support		\|sector=Business Support
	\|version=0.3		\|version=0.4
	\|owner=Jan Schoonderbeek		\|owner=Jan Schoonderbeek
	\|summary=This function serves to increase the maximum load that a given resource can handle, and/or allowing access to instances of the resource spread over multiple sites.		\|summary=This function serves to increase the maximum load that a given resource can handle, and/or allowing access to instances of the resource spread over multiple sites.
	}}		}}
	This function is active in the data traffic between an IT resource (an IT service or application,or a set of different IT services or applications) ) and its consumers, and serves to increase the maximum load that the resource can handle, or to help business continuity by allowing access to instances of the resource spread over multiple sites, or both.		This function is active in the data traffic between an IT resource (an IT service or application,or a set of different IT services or applications) ) and its consumers, and serves to increase the maximum load that the resource can handle, or to help business continuity by allowing access to instances of the resource spread over multiple sites, or both.
	To this end, the function accepts connections from the resource's ~~clients~~, and direct them to an available instance of the IT resource.		To this end, the function accepts connections from the resource's consumers, and direct them to an available instance of the IT resource. Optionally, the service can cache and/or queue traffic.

	Examples of components that deliver Access Distribution functionality are load balancer appliances and a web proxy servers. However, this function is not limited to "pure" network use: IT services may have Access Distribution functionality implemented internally as well.		Examples of components that deliver Access Distribution functionality are load balancer appliances and a web proxy servers. However, this function is not limited to "pure" network use: IT services may have Access Distribution functionality implemented internally as well.
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	\|choice=May		\|choice=May
	\|reason=For a correct distribution of access over distributed services, the Distribution function may need access to session data, which Connection Handling can provide. Furthermore, for a seamless transition of a user session from one part of the distributed service to another, the session may require special attention (e.g. a "session state database").		\|reason=For a correct distribution of access over distributed services, the Distribution function may need access to session data, which Connection Handling can provide. Furthermore, for a seamless transition of a user session from one part of the distributed service to another, the session may require special attention (e.g. a "session state database").
			}}
			{{Generic Pattern Composition Row
			\|function=GF.Queuing
			\|choice=May
			\|reason=Adding Queuing functionality can help optimize traffic processing. Note that addition of Queuing usually also means addition of Caching.
	}}		}}
	{{Generic Pattern Composition Row		{{Generic Pattern Composition Row
	\|function=GF.Caching		\|function=GF.Caching
	\|choice=May		\|choice=May
	\|reason=The Access Distribution Pattern is a very good place to implement caching as it can both ease the load on the distributed service behind this pattern, and speed up their apparent responsiveness.		\|reason=The Access Distribution Pattern is a very good place to implement caching as it can both ease the load on the distributed service behind this pattern, and speed up their apparent responsiveness. Note that Caching supports Queuing, but may also appear when Queuing is not modelled.
	}}		}}
	{{Generic Pattern Composition Row		{{Generic Pattern Composition Row

Jan Schoonderbeek: link fix

2015-01-01T12:52:24Z

link fix

← Older revision		Revision as of 12:52, 1 January 2015
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	\|owner=Jan Schoonderbeek		\|owner=Jan Schoonderbeek
	\|summary=This function serves to increase the maximum load that a given resource can handle, and/or allowing access to instances of the resource spread over multiple sites.		\|summary=This function serves to increase the maximum load that a given resource can handle, and/or allowing access to instances of the resource spread over multiple sites.

	}}		}}
	This function is active in the data traffic between an IT resource (an IT service or application,or a set of different IT services or applications) ) and its consumers, and serves to increase the maximum load that the resource can handle, or to help business continuity by allowing access to instances of the resource spread over multiple sites, or both.		This function is active in the data traffic between an IT resource (an IT service or application,or a set of different IT services or applications) ) and its consumers, and serves to increase the maximum load that the resource can handle, or to help business continuity by allowing access to instances of the resource spread over multiple sites, or both.
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	}}		}}
	{{Pattern Graphic		{{Pattern Graphic
	\|graphic=GP.Access Distribution.png ~~Jump to: navigation, search~~		\|graphic=GP.Access Distribution.png
			\|source=GP.
	\|size=534px		\|size=534px
	\|kind=Generic		\|kind=Generic
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	\|function=GF.Load Balancing		\|function=GF.Load Balancing
	\|choice=May		\|choice=May
	\|reason=Loads may need to be (re)directed, either for an even distribution of load on the distributed service, or to counter the effect of a failure of a component or service in the hinterland. In either case, it's likely that functionality is needed that can provide the Distribution function with the means to sense the need for load balancing, and consequently make a distribution decision.		\|reason=Loads may need to be (re)directed, either for an even distribution of load on the distributed service, or to counter the effect of a failure of a component or service in the hinterland. In either case, it's likely that functionality is needed that can provide the Distribution function with the means to sense the need for load balancing, and consequently make a distribution decision.
	}}		}}
	{{Generic Pattern Composition Row		{{Generic Pattern Composition Row
	\|function=GF.Data Scanning		\|function=GF.Data Scanning
	\|choice=May		\|choice=May
	\|reason=Distribution may occur not only based on the traffic characteristics ("conventional routing") but also on the content of the traffic ("content based routing"). To this end, the Access Distribution pattern should have access to the data of the traffic that's being distributed, and this Generic Function offers that access. As an example: this GF could recognize HTTP headers within network traffic, and direct traffic destined for a particular application to the right application server.		\|reason=Distribution may occur not only based on the traffic characteristics ("conventional routing") but also on the content of the traffic ("content based routing"). To this end, the Access Distribution pattern should have access to the data of the traffic that's being distributed, and this Generic Function offers that access. As an example: this GF could recognize HTTP headers within network traffic, and direct traffic destined for a particular application to the right application server.
	}}		}}
	{{Generic Pattern Composition Row		{{Generic Pattern Composition Row
	\|function=GF.Connection Handling		\|function=GF.Connection Handling
	\|choice=May		\|choice=May
	\|reason=For a correct distribution of access over distributed services, the Distribution function may need access to session data, which Connection Handling can provide. Furthermore, for a seamless transition of a user session from one part of the distributed service to another, the session may require special attention (e.g. a "session state database").		\|reason=For a correct distribution of access over distributed services, the Distribution function may need access to session data, which Connection Handling can provide. Furthermore, for a seamless transition of a user session from one part of the distributed service to another, the session may require special attention (e.g. a "session state database").
	}}		}}
	{{Generic Pattern Composition Row		{{Generic Pattern Composition Row
	\|function=GF.Caching		\|function=GF.Caching
	\|choice=May		\|choice=May
	\|reason=The Access Distribution Pattern is a very good place to implement caching as it can both ease the load on the distributed service behind this pattern, and speed up their apparent responsiveness.		\|reason=The Access Distribution Pattern is a very good place to implement caching as it can both ease the load on the distributed service behind this pattern, and speed up their apparent responsiveness.
	}}		}}
	{{Generic Pattern Composition Row		{{Generic Pattern Composition Row
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	\|service=GS.Facilities Monitoring		\|service=GS.Facilities Monitoring
	\|choice=May		\|choice=May
	\|reason=Access Distribution is usually employed to ensure access to the IT facility that this Pattern is supporting. Thus, many events that occur in an Access Distribution facility are of interest to the IT Operations staff. This means it is desirable to have the facility report directly to (an Operations instance of) Facilities Monitoring.		\|reason=Access Distribution is usually employed to ensure access to the IT facility that this Pattern is supporting. Thus, many events that occur in an Access Distribution facility are of interest to the IT Operations staff. This means it is desirable to have the facility report directly to (an Operations instance of) Facilities Monitoring.
	}}		}}
	{{Table Ending}}		{{Table Ending}}
	{{Text Footer GP}}		{{Text Footer GP}}

Jan Schoonderbeek: New GP

2015-01-01T12:51:45Z

New GP

New page

{{Maturity|3}}
{{Pageheaderbox4GP
|name=Access Distribution
|sector=Business Support
|version=0.3
|owner=Jan Schoonderbeek
|summary=This function serves to increase the maximum load that a given resource can handle, and/or allowing access to instances of the resource spread over multiple sites.

}}
This function is active in the data traffic between an IT resource (an IT service or application,or a set of different IT services or applications) ) and its consumers, and serves to increase the maximum load that the resource can handle, or to help business continuity by allowing access to instances of the resource spread over multiple sites, or both.
To this end, the function accepts connections from the resource's clients, and direct them to an available instance of the IT resource.

Examples of components that deliver Access Distribution functionality are load balancer appliances and a web proxy servers. However, this function is not limited to "pure" network use: IT services may have Access Distribution functionality implemented internally as well.

Note that Access Distribution functionality is often combined with Access Security functionality.
{{Pattern Realizes
|service=GS.Access Distribution
}}
{{Pattern Graphic
|graphic=GP.Access Distribution.png Jump to: navigation, search
|size=534px
|kind=Generic
}}
{{Generic Pattern Composition}}
{{Generic Pattern Composition Row
|function=GF.Distribution
|choice=Must
|reason=This function delivers the core functionality of the pattern. Note that multiple instances of Distribution functionality may use each other to direct data traffic to the correct destination.
}}
{{Generic Pattern Composition Row
|function=GF.Load Balancing
|choice=May
|reason=Loads may need to be (re)directed, either for an even distribution of load on the distributed service, or to counter the effect of a failure of a component or service in the hinterland. In either case, it's likely that functionality is needed that can provide the Distribution function with the means to sense the need for load balancing, and consequently make a distribution decision.
}}
{{Generic Pattern Composition Row
|function=GF.Data Scanning
|choice=May
|reason=Distribution may occur not only based on the traffic characteristics ("conventional routing") but also on the content of the traffic ("content based routing"). To this end, the Access Distribution pattern should have access to the data of the traffic that's being distributed, and this Generic Function offers that access. As an example: this GF could recognize HTTP headers within network traffic, and direct traffic destined for a particular application to the right application server.
}}
{{Generic Pattern Composition Row
|function=GF.Connection Handling
|choice=May
|reason=For a correct distribution of access over distributed services, the Distribution function may need access to session data, which Connection Handling can provide. Furthermore, for a seamless transition of a user session from one part of the distributed service to another, the session may require special attention (e.g. a "session state database").
}}
{{Generic Pattern Composition Row
|function=GF.Caching
|choice=May
|reason=The Access Distribution Pattern is a very good place to implement caching as it can both ease the load on the distributed service behind this pattern, and speed up their apparent responsiveness.
}}
{{Generic Pattern Composition Row
|function=GF.Controlling
|choice=Must
|reason=Access to the configuration and operation of this Pattern is most always restricted. Furthermore, special care is required to ensure sufficient access to the configuration and operation when a sizeable incident impacts IT operations: e.g. when a site outage causes network fail-over, IT operations must be able to check and adapt the configuration of Access Distribution in the aftermath.
}}
{{Table Ending}}
{{Pattern Adjacent Services}}
{{Generic Pattern Adjacent Service Row
|service=GS.Data Transport
|choice=Must
|reason=While virtually all Generic Patterns have a relation with Data Transport, this relation is more noteworthy for Access Distribution, since the designer will have to fit Access Distribution correctly between a Data Transport instance and the IT facility for which it is distributing access. The presence of (one or more instances of) Data Transport service serves to model all concerns relating to the correct fit.
}}
{{Generic Pattern Adjacent Service Row
|service=GS.Facilities Monitoring
|choice=May
|reason=Access Distribution is usually employed to ensure access to the IT facility that this Pattern is supporting. Thus, many events that occur in an Access Distribution facility are of interest to the IT Operations staff. This means it is desirable to have the facility report directly to (an Operations instance of) Facilities Monitoring.
}}
{{Table Ending}}
{{Text Footer GP}}