Return-Path: From: Michael Richardson To: Alexander Aring cc: Network Development , Jukka Rissanen , Luiz Augusto von Dentz , "linux-wpan\@vger.kernel.org" , Linux Bluetooth Subject: Re: bluetooth 6lowpan interfaces are not virtual anymore In-Reply-To: <2d178eb8-3fbc-3385-6e0c-fa9941713959@pengutronix.de> References: <2d178eb8-3fbc-3385-6e0c-fa9941713959@pengutronix.de> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Date: Tue, 18 Apr 2017 12:59:43 -0400 Message-ID: <28530.1492534783@obiwan.sandelman.ca> Sender: linux-wpan-owner@vger.kernel.org List-ID: --=-=-= Content-Type: text/plain Alexander Aring wrote: > What does the 6LoWPAN interface? > It will do a protocol change (an adaptation, because 6LoWPAN should > provide the same functionality as IPv6) from IPv6 to 6LoWPAN (tx) and > vice versa for (rx). In my opinion this should be handled as a virtual > interface and not as an interface with a queue. I wonder if modeling all the 6lowpan work as a virtual interface is even the right abstraction anymore. I think that it was certainly a good model at the time the interface was created, given no other clear thing to do. We don't model IPv6 ND (or IPv4 ARP) or fragmentation in general as a virtual interface on top of a raw interface. Really, it's a set of operations that happens on a packet. 802.15.4 is notable for it's current lack of an ethertype (IEEE is fixing that though), so you can't actually run different protocols on the same PANID. BT does have a variety of different protocols, and IPv6 is only one. In a classic SVR4 STREAMS works, it would have been just another module. (No, I'm not a fan of *STREAMS* or of SVR4 in general, although I liked some of the ideas). At this time, things like PANID and channel are set on the wpanX interface. If they were set on the 6lowpan interface, such that one could (in theory, assuming the hardware could do it, which some can, and some can not) then one could have multiple 6lowpan interfaces on top of the same wpanX. Or one could run some non-IP protocol like pre-IP Zigbee on one PANID while one runs 6lowpan on another. THEN, a virtual interface would make sense for the same reason VLAN interfaces make sense. -- ] Never tell me the odds! | ipv6 mesh networks [ ] Michael Richardson, Sandelman Software Works | network architect [ ] mcr@sandelman.ca http://www.sandelman.ca/ | ruby on rails [ --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEbsyLEzg/qUTA43uogItw+93Q3WUFAlj2Rf8ACgkQgItw+93Q 3WWnQQgAgkXo44pEodfLnFpGEo4hSX/79hZhA2np/WAx0tLbZlYwfgnAExG5II/2 j+eWevu5kW62oCaP3A7YckJ2WZXhiMI4UGqEPEJIC614GK7cZ8tQImflXnklpUO1 kjeecZchtGUuBV7ZgD7AT2z83k2IU7r3nAf3msLB7YnISvS3HKlGaI8M901T6JZG wrjjJikMVklZw9809cVj09AT4YKTtOiwNzIvGKZ4J/qCqapcfrj/5chPwoxGuiUh JK2eKe5QUb37Bknso7i2gDf1LM5Oy1QlljzWPJ0b47gqppCKOwhIUvxbrcZygN8y NUrrQM+G68yn5UYszmUdjkFWXE32hA== =ntFW -----END PGP SIGNATURE----- --=-=-=--