Generic mac
Transcript of Generic mac
1. 1
Generic Framework Architecture
For Expediting Development of
Layer 2 MACs
Soma Bandyopadhyay
Convergence Solutions Practice
TATA Consultancy Services Limited, Kolkata
2. 2
Introduction
Features
Common functionalities
System model
System Architecture
Thread module
Core-MAC
State Handler matrix
MAC-SAP-Interface
PHY-SAP-Interface
Library
OSAL
Case study -WMAN MAC implementation on generic MAC framework
Achievements
Road-Map
AGENDA
3. 3
Introduction
Generic MAC development framework -
Can be used as basic development framework for any Media Access Control (MAC) /(Layer 2) protocol.
Reduces the development time for any MAC stack development
Specific definition for specific MAC needs to be added mostly in the header files and the existing data structure needs to be updated accordingly.
4. 4
Generic software architecture for developing any type of MAC
Network and physical layer abstraction modules.
A common library- exposes different generic application programming interface (API).
Unique Macros (pre-processor definitions used in C programming language) to route to different state handlers based on the current state and incoming event as defined in the two-dimensional state-event matrix.
This framework ensures towards the faster development of MAC stack, thereby reducing the time-to-market.
Salient Aspects
5. 5
Common Functionalities
Specific MAC
Routing to state handlers
OSAL-Operating system adaptation layer
PHY Abstraction module
Common library
Message Parsing
Message generation
State handlers
Specific MAC functionalities
Generic MAC features common to all MAC
MAC framework
Inputs to framework
6. 6
System Model
Based on a multithreaded structure
Specific MAC definitions are mostly defined in header files
Thread modules :Generated by the initialization function
MAC-SAP-Interface –Provides Layer3(Network Layer) abstraction
Core-MAC-
Provides main state-machine implementation, Synchronization with other thread modules and PHY
Collects the definition for the specific MAC from the header files
PHY-SAP–Interface -Provides Layer1(Phy Layer) abstraction
Thread modules can generate further threads
Library –Provides all the basic functionalities
OSAL(Operating System Adaptation Layer)-
Encapsulates all the system calls
7. 7
System Architecture
Core MAC Framework() -Initialization function
Library OSAL
Device Driver
MAC SAP Interface
PHY-SAP Interface
Physical Layer
8. 8
Thread Modules – Core-MAC
Core-MAC- Main control module of the MACKeeps track of the current state
Keeps synchronization with all the thread modules
Routes to state-handlers in the state-event handler matrix by using a Macro
current state and the event occurrence number are used as inputs to the Macro
Triggers the output event corresponding to the current state and the event occurrence number to the destination
Generates own Service Data Unit (SDU) from the higher layer Protocol Data Unit (PDU)
Decodes/Parse the incoming event
Initiates the data path
Manages MIB & Authentication
9. 9
State Handler Matrix
Callback
State0_Event0 ()
Struct output-event-
Output event-id
Destination- id
Callback
State1_Event0()
Struct output-event-
Output event-id
Destination- id
Callback
State2_Event0()
Struct output-event-
Output event-id
Destination- id
Callback
State0_Event1()
Struct output-event-
Output event-id
Destination- id
Callback
State1_Event1()
Struct output-event-
Output event-id
Destination- id
Callback
State2_Event1()
Struct output-event-
Output event-id
Destination- id
Callback
State0_Event2()
Struct output-event-
Output event-id
Destination- id
Callback
State1_Event2()
Struct output-event-
Output event-id
Destination- id
Callback
State2_Event2()
Struct output-event-
Output event-id
Destination- id
State
State0 State1 State2
Events
Event0
Event1
Event2
Implemented as a two dimensional array of structure
Looked up by current state and row id
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Thread Modules – MAC-SAP-Interface
Layer 3 MAC-SAP-Interface
Capture thread
Core-MAC
SDUTrigger data capture /Send data to layer 3
Buffers , classifies packet
Uses library calls
Packet
Packet
Reconstructs , sends packet to layer 3, Uses library calls
Reconstruct thread
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Thread Modules – PHY-SAP-Interface
Layer 1/PHY PHY-SAP-Interface
Receive thread
PHY-SAP-MIB thread
Core-MAC
SDUTrigger data capture /Send data to layer 3
Buffers , Receives packet, Checks whether PHY is dead or alive. Uses library calls
MIB-Info
Packet
Keeps track of PHY-MIB data , Uses library calls
Send function is encapsulated within Library function , it is considered as a non blocking function and no thread is generated for it.
12. 12
Library-
Makes available the basic functionalities by exposing different generic Application Programming Interface (API).
Protocol-specific functionalities can be added to these APIs.
Main APIS:
Message receive & Send to the peer MAC and its own threads
MAC Protocol Data Unit (PDU)(payload+header) generation
Fragment & defragment PDU
Classify & Reconstruct packet
Parsing/decode message
Determination of message identifier
Uses the OSAL to access any System Call
Library
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OSAL-
Provides an adaptation layer on top of the operating systems
Establishs a path between the MAC and the device driver of the physical layer device
Wraps all the Inter Process Communication (IPCs) (like message queue operations, semaphores for mutual exclusion, event synchronization, and timer handlers etc.)
OSAL –Operating System Adaptation Layer
14. 14
Case Study –WMAN MAC On Generic Framework
ClassifierMAC-SAP Interface thread
(Convergence sub-layer)
Core MAC(Common Part Sub-Layer)
PHY-ManagerReceive
Re-constructor
PHY-MIB
SFID, QOS, CID
Message queue
OSAL
Library
PHY Device Driver
PHY -OFDM
PHY_SAP
15. 15
Case Study –WMAN MAC On Generic Framework Contd.
Wireless Metropolitan Area Network (WMAN) MAC stack development is going on based on generic MAC framework
Joint partnership project is already signed up with CDOT
Objective :
Indigenous WiMAX product development
To provide high-speed wireless Internet access to rural as well as urban areas
TCS will provide the Platform independent MAC for Base Station & Service Station
Target hardware with RF & PHY block will be provided by CDOT
TCS will port the platform independent MAC on CDOT board
Finally WMAN stack will be integrated with MAC for Milton as Customer Premises Equipment CPE)/Service Station.
16. 16
Achievements
Reduction in MAC development time –40% approx.
Eases the porting activity
Adaptation of different layer 3(network-layer) data traffic
Adaptation of different PHY (Physical layer)
17. 17
Road-Map
Packaging of the framework as a WizardUsed as a tool to perform some of the work in an automated way
Creates the source files for the framework
Take the Specific MAC definition as Inputs
Enriching library by adding following functionalities
Authentication
Packing & Unpacking of packet
Padding
18. 18
Thank You
19. 19
OSAL –Operating System Adaptation Layer
MIB- Management Interface Base
WiMAX- Worldwide Interoperability Microwave Access
SFID –Service Flow identifier
QOS- Quality of Service
CID –Connection identifier
Layer 3/L3 – Network layer
Layer2 /L2 –MAC layer
PHY- Physical
Acronym