[avahi] scalability of avahi (or mdns-sd in general)

[Nicholas Andrews]

In a talk Stuart Cheshire gave at Google
(http://video.google.com/videoplay?docid=-7398680103951126462&q=bonjour)
he goes as low as 100 hosts as already being too many. He isn't clear,
however, on if that means that it would generate too much chatter to
be practical or just more than what the protocol is supposed to be
used for (and indeed there is no mention of the type of network).

I know that SLP allows scopes to be defined to help scale to larger
networks, and I was wondering if there was (or could be) an equivalent
with mDNS-SD? My application is a wireless ad-hoc network, so the
question of overhead is an important one.

-Nick


On 6/15/06, Lennart Poettering <lennart at poettering.net> wrote:
> On Thu, 15.06.06 17:17, Nicholas Andrews (tar.bz2 at gmail.com) wrote:
>
> > Hello,
> >
> > I'm interested in how well mDNS-SD scales. I have heard it described
> > as a lightweight protocol, but I've never seen any numbers. At what
> > point does it become impractical to use it for service discovery?
>
> According to Apple mDNS scales well for up to 1000 hosts. I don't know
> if they did simulations to prove that claim. And I do not know if
> Avahi actually is compatible enough with Bonjour that the claim still
> holds. And finally I know nothing about the network technology they
> used for that claim (100mbit ethernet, gigabit ethernet, WLAN?).
>
> In short: it's all very vague, the only value we ever heard or read
> was 1000 hosts.
>
> A side node: I haven't seen anything about the number of *services*
> mDNS scales to. Only *hosts*, which is not really the same.
>
> Lennart
>
> --
> Lennart Poettering; lennart [at] poettering [dot] net
> ICQ# 11060553; GPG 0x1A015CC4; http://0pointer.net/lennart/
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