## Channel Manager
* responsible for creating, managing and closing L2CAP channels.
* uses the L2CAP protocol to interact with a channel manager on a remote (peer) device to
* create these L2CAP channels
* connect their endpoints to the appropriate entities.
## Channel Manager
* interacts with its local link manager or an AMP PAL to
* create new logical links (if necessary)
* configure these links to provide the required quality of service for the type of data being transported.
## L2CAP Resource Manager
* managing the ordering of submission of PDU fragments to the baseband.
* Schedule Resources to access the physical channel.
* carry out traffic conformance policing to ensure negotiated QoS settings is met.
## Security Manager Protocol
* the P2P protocol used to generate encryption keys and identity keys.
* operates over a dedicated fixed L2CAP channel.
* manages storage of the encryption keys and identity keys.
* responsible for generating random addresses and resolving random addresses to known device identities.
* only used in LE systems.
## Attribute Protocol
* implements the peer-to-peer protocol between an attribute server and an attribute client.
* communicate over a dedicated fixed L2CAP channel.
* The ATT client sends commands, requests, and confirmations to the ATT server.
* The ATT server sends responses, notifications and indications to the client.
## Generic Attribute Profile
* represents the functionality of the attribute server and, optionally, the attribute client.
* describes the hierarchy of services, characteristics and attributes used in the attribute server.
* The block provides interfaces for discovering, reading, writing and indicating of service characteristics and attributes.
* used on LE devices for LE profile service discovery.
Generic Access Profile
- represents the base functionality common to all Bluetooth devices.
- GAP services include:
- device discovery
- connection modes
- association models
- service discovery