[avahi] Multi-home uses

[Lennart Poettering]

On Fri, 05.09.08 14:14, Del Merritt (del at alum.mit.edu) wrote:

> I am looking for the description of how to properly implement and 
> configure a multi-homed system.  E.g., say I have a laptop or cell-phone 
> or PDA with both a WiFi card and a BlueTooth adapter, and assume that 
> the Bluetooth and TCP/IP stacks support BNEP (TCP/IP over Bluetooth).
> 
> If I walk my device into a room, it may find the Wireless Access Point 
> first, which may be "traditional" DHCP or it could be Zeroconf/Bonjour.  
> As I walk closer to some other device, say a high-end printer, I may 
> come in range of the Bluetooth network the printer is willing to support.
> 
> So the question: does Avahi - or the Bonjour/Zeroconf standard - specify 
> how to function in what can be two independent networks, each having 
> their own routes and potentially their own .local domains?

mDNS/DNS-SD works fine and out-of-the-box with multi-homed networks.

IPV4ll can only be used on one network at a time, because most OSes
generally allow setting only a single route to 169.254.0.0/24. If your
distro is well behaving and following my recommendations from
http://avahi.org/wiki/AvahiAutoipd (especially the part about
"Multihomed hosts") then the network that will be reachable via IPv4LL
is always the one whose iface is the one with the lowest
ifindex. Which is kind of deterministic and robust though not
necessarily the right choice in all cases.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
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