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.. Licensed under the Apache License, Version 2.0 (the "License");
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.. _server_capability:

**************************
Manage Server Capabilities
**************************
Server capabilities are designed to enable users with the Operations or Admin :term:`Role` to control the flow of :term:`Delivery Service` traffic through only the :term:`cache servers` (:term:`Edge` or :term:`Mid`) that have the required capabilities. For example, :term:`Delivery Services` designed to serve large binary files should only have requests routed to :term:`cache servers` with sufficient disk cache. Currently, this can be controlled at the :term:`Edge-tier` where system operators can explicitly assign only :term:`Edge-tier caches` with sufficient disk cache to the :term:`Delivery Service`. However, operators do not have control of :term:`Mid-tier cache` assignments and cannot dictate which :term:`Mid-tier caches` are qualified to serve these large binary files. This will cause a problem if a :term:`Mid-tier cache` with insufficient disk cache is asked to serve the :term:`Delivery Services`' large binary files.

A list of the server capabilities can be found under :menuselection:`Configure --> Server Capabilities`. Users with a higher-level :term:`Role` ("operations" or "admin") can create or delete server capabilities. Server capabilities can only be deleted if they are not currently being used by a :term:`cache server` or required by a :term:`Delivery Service`.

.. figure:: server_capability/server_caps_table.png
	:align: center
	:alt: A screenshot of the Traffic Portal UI depicting an example list of Server Capabilities

	Example Server Capabilities Listing

.. _server_server_capabilities:

Manage server capabilities assigned to a server
===============================================
Users with the Operations or Admin :term:`Role` can associate one or more server capabilities with a :term:`cache servers` (:term:`Edge` or :term:`Mid`) by navigating to a server via :menuselection:`Configure --> Servers` and using the context menu for the server table and selecting :menuselection:`Manage Capabilities` or by navigating to :menuselection:`Configure --> Servers --> Server --> More --> Manage Capabilities`.

.. figure:: server_capability/server_server_caps_table.png
	:align: center
	:alt: A screenshot of the Traffic Portal UI depicting an example list of Server Capabilities attached to a Server

	Example Server Capabilities for a Server Listing

.. _delivery_service_required_server_capabilities:

Manage delivery service required server capabilities
====================================================
Users with the Operations or Admin :term:`Role` can associate one or more required server capabilities with a :term:`Delivery Service` by navigating to a :term:`Delivery Service` via :menuselection:`Services --> Delivery Services` and using the context menu for the :term:`Delivery Services` table and selecting :menuselection:`Manage Required Server Capabilities` or by navigating to :menuselection:`Services --> Delivery Services --> Delivery Service --> More --> Manage Required Server Capabilities`.

Adding a required server capability to a :term:`Delivery Service` will ensure two things:

1. Only :term:`Edge-tier caches` with the required capability can be assigned to the :term:`Delivery Service`
2. Only :term:`Mid-tier caches` with the required capability will handle requests of the :term:`Delivery Service` (if applicable)

.. figure:: server_capability/ds_server_caps_table.png
	:align: center
	:alt: A screenshot of the Traffic Portal UI depicting an example list of Required Server Capabilities for a Delivery Service

	Example Required Server Capabilities for a Delivery Service Listing


