Re: [Bluez-devel] Piconet Routing

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Since Bluetooth uses Time Division Duplex, a slave is not allowed to
talk to another slave in the same Piconet. The logical consequence 

must

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be that the data is routed over the master. I've used l2test to 

check if

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l2cap does this kind of routing automatically. It doesn't but rather
creates a new, direct acl link to the remote slave device 

(scatternet).

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I don't know how it is with rfcomm, but I suppose it's the same. My
question: Is there any automatic Piconet Routing inside BlueZ or 

does

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one have to implement it by oneself?

you must do it by yourself, because even if the master manages to put
all devices into the same piconet the connections are point to point.

TCP connections are also point to point, but since it's built on top
of IP, it goes (transparently) over many routers. Before I tested it,
I thought the link manager would take care of this. How does the
communiction of many BT devices work in practice? Who manages this
routing, since one device can only be point-to-point-connected to 2
devices (an this doesn't work really smooth)?

[No, a master can be P2P-connected to up to 7 active slaves in a piconet,
and if you support scatternets then you can in theory also be P2P-connected
to several masters (although this is indeed not very smooth in BT1.2).]

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There must be one
controlling instance. One cannot let the different applications handle
this, can one?

this is true, but the problem is, that a slave does not know to which
other slaves a master is connected. There is no routing stuff like in IP
and you can't retrieve these information from the HCI layer.

A solution to the OP's problem is to use the PAN profile.  The master (GN)
will then automatically "route" (bridge, actually) BNEP (Ethernet) packets
between the slaves (PANUs).

Mark

--
CPC/IP - A TCP/IP stack for Amstrad CPCs
-- http://www.nenie.org/cpcip/
"Z88 vs CPC? Christ. How did we miss that platform war?"
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