Subject: [mdnsext] 802.11 addition to requirements documents

From: Matthew Gast <[email-masked]>
Date: Wed, 7 Nov 2012 06:59:07 +0000

In section 1, there is a paragraph describing how DNS-SD is not suitable
for emerging technologies (beginning "Similarly, DNS-SD/mDNS in its
present form...").  One point that was brought up in today's BoF
discussion is that 802.11 is also different from the Ethernet link layers
that supported service discovery.  As a straw-man, I'd suggest text like
the following, to get at the problems related to high overhead from
multicast traffic and relatively high packet loss of multicast frames:

"Wireless networks such as 802.11 [IEEE802.11] may be adversely affected
by extensive multicast transmissions to support service discovery.  As
802.11 is typically deployed, multicast frames are sent at low data rates.
 Low-rate frames require more time to transmit frames, which increases
network overhead.  To preserve network capacity for application traffic,
administrators of large-scale networks may block some or all multicast
traffic.  In 802.11, multicast frames are not positively acknowledged and
it is common to observe much higher loss of multicast frames on 802.11
than other IEEE 802 networks."

The reference to [IEEE802.11] would be to IEEE Std 802.11-2012, IEEE
Standard for Information technology--Telecommunications and information
exchange between systems Local and metropolitan area networks--Specific
requirements Part 11: Wireless LAN Medium Access Control (MAC) and
Physical Layer (PHY) Specifications.

Matthew