Introduction
============
+The IEEE 802.15.4 working group focuses on standartization of bottom
+two layers: Medium Accsess Control (MAC) and Physical (PHY). And there
+are mainly two options available for upper layers:
+ - ZigBee - proprietary protocol from ZigBee Alliance
+ - 6LowPAN - IPv6 networking over low rate personal area networks
The Linux-ZigBee project goal is to provide complete implementation
-of IEEE 802.15.4 / ZigBee / 6LoWPAN protocols. IEEE 802.15.4 is a stack
+of IEEE 802.15.4 and 6LoWPAN protocols. IEEE 802.15.4 is a stack
of protocols for organizing Low-Rate Wireless Personal Area Networks.
-Currently only IEEE 802.15.4 layer is implemented. We have chosen
-to use plain Berkeley socket API, the generic Linux networking stack
-to transfer IEEE 802.15.4 messages and a special protocol over genetlink
-for configuration/management
+The stack is composed of three main parts:
+ - IEEE 802.15.4 layer; We have chosen to use plain Berkeley socket API,
+ the generic Linux networking stack to transfer IEEE 802.15.4 messages
+ and a special protocol over genetlink for configuration/management
+ - MAC - provides access to shared channel and reliable data delivery
+ - PHY - represents device drivers
Socket API
One can use SOCK_RAW for passing raw data towards device xmit function. YMMV.
-MLME - MAC Level Management
-============================
-
-Most of IEEE 802.15.4 MLME interfaces are directly mapped on netlink commands.
-See the include/net/nl802154.h header. Our userspace tools package
-(see above) provides CLI configuration utility for radio interfaces and simple
-coordinator for IEEE 802.15.4 networks as an example users of MLME protocol.
-
-
Kernel side
=============
Those types of devices require different approach to be hooked into Linux kernel.
+MLME - MAC Level Management
+============================
+
+Most of IEEE 802.15.4 MLME interfaces are directly mapped on netlink commands.
+See the include/net/nl802154.h header. Our userspace tools package
+(see above) provides CLI configuration utility for radio interfaces and simple
+coordinator for IEEE 802.15.4 networks as an example users of MLME protocol.
+
+
HardMAC
=======
SoftMAC
=======
-We are going to provide intermediate layer implementing IEEE 802.15.4 MAC
-in software. This is currently WIP.
+The MAC is the middle layer in the IEEE 802.15.4 Linux stack. This moment it
+provides interface for drivers registration and management of slave interfaces.
+
+NOTE: Currently the only monitor device type is supported - it's IEEE 802.15.4
+stack interface for network sniffers (e.g. WireShark).
+
+This layer is going to be extended soon.
See header include/net/mac802154.h and several drivers in drivers/ieee802154/.
+
+Device drivers API
+==================
+
+The include/net/mac802154.h defines following functions:
+ - struct ieee802154_dev *ieee802154_alloc_device
+ (size_t priv_size, struct ieee802154_ops *ops):
+ allocation of IEEE 802.15.4 compatible device
+
+ - void ieee802154_free_device(struct ieee802154_dev *dev):
+ freeing allocated device
+
+ - int ieee802154_register_device(struct ieee802154_dev *dev):
+ register PHY in the system
+
+ - void ieee802154_unregister_device(struct ieee802154_dev *dev):
+ freeing registered PHY
+
+Moreover IEEE 802.15.4 device operations structure should be filled.
+
+Fake drivers
+============
+
+In addition there are two drivers available which simulate real devices with
+HardMAC (fakehard) and SoftMAC (fakelb - IEEE 802.15.4 loopback driver)
+interfaces. This option provides possibility to test and debug stack without
+usage of real hardware.
+
+See sources in drivers/ieee802154 folder for more details.
+
+
+6LoWPAN Linux implementation
+============================
+
+The IEEE 802.15.4 standard specifies an MTU of 128 bytes, yielding about 80
+octets of actual MAC payload once security is turned on, on a wireless link
+with a link throughput of 250 kbps or less. The 6LoWPAN adaptation format
+[RFC4944] was specified to carry IPv6 datagrams over such constrained links,
+taking into account limited bandwidth, memory, or energy resources that are
+expected in applications such as wireless Sensor Networks. [RFC4944] defines
+a Mesh Addressing header to support sub-IP forwarding, a Fragmentation header
+to support the IPv6 minimum MTU requirement [RFC2460], and stateless header
+compression for IPv6 datagrams (LOWPAN_HC1 and LOWPAN_HC2) to reduce the
+relatively large IPv6 and UDP headers down to (in the best case) several bytes.
+
+In Semptember 2011 the standard update was published - [RFC6282].
+It deprecates HC1 and HC2 compression and defines IPHC encoding format which is
+used in this Linux implementation.
+
+All the code related to 6lowpan you may find in files: net/ieee802154/6lowpan.*
+
+To setup 6lowpan interface you need (busybox release > 1.17.0):
+1. Add IEEE802.15.4 interface and initialize PANid;
+2. Add 6lowpan interface by command like:
+ # ip link add link wpan0 name lowpan0 type lowpan
+3. Set MAC (if needs):
+ # ip link set lowpan0 address de:ad:be:ef:ca:fe:ba:be
+4. Bring up 'lowpan0' interface
projects / linux-2.6-block.git / blobdiff