I am interested in developing applications using the XBee products. However I think things are a bit confusing so I want to hear your opinion.
I am reading the forums and I can see people referring to the XBee products from sparkfun and talk about Zigbee. However these products are not Zigbee (am I right?). They just use the lower layer 802.15.4 same as Zigbee.
Zigbee is at higher layer which has the capability to establish a mesh network. Which is actually what I am looking for :). I cant find any products in sparkfun which support mesh. That is why I am a bit confused.
I’ve been working with the XBee Pro modules and as far as I understand, they do implement at least a part, if not all of the ZigBee stack. For example, you can set a module to be an edge mode or a coordinator mode. There are normal ZigBee addresses (64bit) and shorthand ones (16bit). Or is this all a part of 802.15.4?
Digi/Maxstream do implement extensions that appear to go beyond ZigBee (additional headers to prevent duplicate packets in complex topologies) but when you turn that off as far as I understand you get ZigBee proper.
Of course I don’t have any other ZigBee modules around (and they would be 802.15.4 anyway), so it’s hard/impossible for me to tell the difference between ZigBee proper and 802.15.4.
According to Wikipedia, 802.15.4 is the specification for ZigBee and ZigBee is basically the 802.15.4 brand. Maybe I misunderstood though.
That’s kind of what I thought at first, but the 64/16 bit node addresses, the PAN identifier, and the coordinator node business are all at the 802.15.4 layer.
802.15.4 defines:
physical layer: frequency and modulation (2.4GHz 16-QAM, 915 MHz and 868 MHz DSSS-BPSK) and packet format
medium access control: timing, associating with a coordinator node, addressing, collision avoidance, retransmission, that kind of thing
2-hop routing through the coordinator node
some encryption stuff
Built on top of that, Zigbee defines:
The NWK layer:
AODV-style multihop mesh routing
associating with a network (not just the local coordinator node)
more encryption and authentication and stuff
The APL (application) layer:
allowing nodes to expose individual values and knobs (e.g. individual switches, sensors, and actuators within a node)
“profiles” for various kinds of devices
binding exposed values to exposed knobs (like lightswitch → light)
indirect routing of those bindings
The 802.15.4 spec provides stuff that’s pretty much parallel to what 802.11 or 802.3 provides. Zigbee is one set of protocols you can run over it. There’s also work on running IP over 802.15.4 ([6LoWPAN), which would be an alternative to Zigbee but would still use the 802.15.4 layers. And of course you can run random non-Zigbee protocols over 802.15.4, which seems to be what everyone does in practice with the XBee modules.](IPv6 over Low power WPAN (6lowpan))
I am interested in developing applications using the XBee products. However I think things are a bit confusing so I want to hear your opinion.
I am reading the forums and I can see people referring to the XBee products from sparkfun and talk about Zigbee. However these products are not Zigbee (am I right?). They just use the lower layer 802.15.4 same as Zigbee.
Zigbee is at higher layer which has the capability to establish a mesh network. Which is actually what I am looking for :). I cant find any products in sparkfun which support mesh. That is why I am a bit confused.
So does sparkfun has actual Zigbee modules?
Thank you
If you want to do meshing (don’t, unless you MUST have that topology), then look at the XBee SERIES 2 modules, based on Ember’s technology. XBee series one (and XBee PRO) use Freescale’s chipset and ye ole Figure8 ZigBee stack; not as preferrable for Zigbee, but series 1 are best choice for '15.4 non-zigbee apps.
And there are many other vendors’ modules from which to choose.
stevech:
XBee series one (and XBee PRO) use Freescale’s chipset and ye ole Figure8 ZigBee stack; not as preferrable for Zigbee
I am sorry I did not quite understand what you want to say, could you explain?
Well actually I do want the mesh topology for a WSN project we will start here, so I guess I need ZigBee. What other products do you suggest for ZigBee that would interface easily and have easy connectivity (I have never worked with SMD)
I am a newbie to XBees and just made my first “mesh” the modules XBees serie 2.5 can load differnt types of Bios/firmware and take diffrent roles…
the ZNet 2.5 can defnetly do mesh!
i just upgraded the modules to ZB bios (free download!) and it goes even more ZigBee …
cut from the release notes:
“The 2x2x ZB firmware release can be installed on any XBee/XBee-PRO ZNet 2.5 (formerly Series 2) module, as they have identical hardware. ZNet 2.5 modules run the proven “designed for ZigBee” EmberZNet 2.5 ZigBee stack. ZB modules run the next-generation EmberZNet PRO 3.1 ZigBee stack based on the latest ZigBee PRO feature set (also known as ZigBee 2007).”
"*** ZB 2x2x Release Supported Features
API and AT command support
Pin sleep and cyclic sleep end devices
ZigBee PRO 64-bit extended PAN ID support
ZigBee stack profile setting is configurable (ZS command)
Remote configuration of module parameters via API remote command frames
Raw ZigBee APS layer access through explicit transmit API frame (0x11). APS endpoint, cluster ID, profile ID fields are configurable
ZigBee security support. Network and trust center link keys can be configured or received when joining
"
as i sad earlier i just set up my first cordinator-router-endnode network and i am happy as on cristmas eve
stevech:
XBee series one (and XBee PRO) use Freescale’s chipset and ye ole Figure8 ZigBee stack; not as preferrable for Zigbee
I am sorry I did not quite understand what you want to say, could you explain?
Well actually I do want the mesh topology for a WSN project we will start here, so I guess I need ZigBee. What other products do you suggest for ZigBee that would interface easily and have easy connectivity (I have never worked with SMD)
Thank you.
“WSN” is ?
consider mesh versus cluster tree versus star topology.
consider if you can get by with just 802.15.4 and your own simple node addressing software. That’s what 80% or more are doing today.
If meshing:
Consider '15.4 modules used with (a) ZigBee PRO which lacks battery powered routing node capability; (b) 6LoPAN; (c) ISA SP100a; (d) proprietary meshing, e.g., that from Dust, Inc.,m Crossbow, Open Source such as from UCSB/UCLA, or Digi’s ZigBee alternative.
The Digi modules should be able to support mesh networks. Currently, it seems they are limited to 8 nodes. This includes either routers or end devices. We had a discussion about this on my forum:
the modules XBees serie 2.5 can load differnt types of Bios/firmware and take diffrent roles…