On Thu, Jan 19, 2012 at 4:55 PM, Grant Edwards <[email protected]> wrote: > On 2012-01-19, Michael Mol <[email protected]> wrote: > >> Indeed. Other reasons to avoid using LL addresses unless necessary: >> What if the MAC address on the server changes? > > It won't. It's an embedded device with a hard-wired MAC that the user > can't change.
It was more a philosophical question, not one of the specific use case. In most systems, hardware NICs fail and may be replaced. (Well, virtualization is making that a bit odd, but still.) I have ideas about your use case, but I can't and won't judge because I don't know enough specifics. Your product, not mine. :) > >> What if your network grows to have hundreds of clients? > > Then people probably won't be using L-L addresses. However, for a > network that consists of 6 small devices all living inside a cabinet > with no router, DHCP server, or connection to the outside workd, L-L > is great. Sure, so long as various applications get fixed to understand LL addresses and are corrected to direct traffic to the appropriate interfaces, which is something I'd definitely like to see. >> Do you really want that much broadcast and wide multicast (think >> DNS-SD and NTP in multicast mode) traffic on the same Ethernet >> segment? > > That bit I don't understand. It's no worse that ARP, and we seem to > live with that quite easily. Not just arp, but actual broadcast/multicast data. If you've ever run PulseAudio and enabled network sources and sinks on a couple boxes, you might have accidentally discovered an easy way to bring a wireless network to its knees. And that's just something I've had personal experience with. Come to think of it, that's a good reason I should continue to keep my home wired and wireless networks on separate subnets, and not simply bridged as I'd done at the time. One anecdote a friend of mine gave me...there was a network he was brought in to manage where he discovered that a huge campus of over a thousand hosts was configured as one large ethernet segment with various-speed links bridging smaller islands. The slower links were absolutely flooded with arp and netbios broadcasts, and the network moved along at a crawl. Chopping that up into a few routed subnets gave the entire network a massive performance boost. > >> LL addresses are very useful for diagnostic and investigation >> purposes, of course. > > Indeed, and that's what I'm doing. -- :wq
