The other thing I noticed is that my ATV seems to be popping in and out of the bonjour device list ever 30 minutes. Note that even when it is on the list using the dns-sd -B _raop._tcp command, it is NOT pingable. It does pop in and out of the airplay list on iOS devices, and in iTunes. If I try to connect to it when it shows up in the airplay list on the iOS device or iTunes, it FAILS to connect. (Timeout.) This is the NEW Apple TV that I just bought, but my old one does this on my network as well. I played around with a bunch of settings on my linksys router yesterday, but none of the router changes made any difference.
C:\Users\Frank40636>dns-sd -B _raop._tcp
Browsing for _raop._tcp
Timestamp A/R Flags if Domain Service Type Instance Name
7:40:40.928 Add 2 18 local. _raop._tcp. 001CB3AB59C1@Patio
7:40:40.944 Add 2 18 local. _raop._tcp. 001B63233F53@Living Room
7:40:40.959 Add 2 18 local. _raop._tcp. 0014516DA87F@Basement
7:50:41.194 Add 2 18 local. _raop._tcp. 68644B1263CE@Apple TV
8:20:39.261 Rmv 0 18 local. _raop._tcp. 68644B1263CE@Apple TV
8:20:40.945 Add 2 18 local. _raop._tcp. 68644B1263CE@Apple TV
8:50:39.245 Rmv 0 18 local. _raop._tcp. 68644B1263CE@Apple TV
8:50:41.148 Add 2 18 local. _raop._tcp. 68644B1263CE@Apple TV
9:20:39.244 Rmv 0 18 local. _raop._tcp. 68644B1263CE@Apple TV
9:20:41.038 Add 2 18 local. _raop._tcp. 68644B1263CE@Apple TV
9:50:39.219 Rmv 0 18 local. _raop._tcp. 68644B1263CE@Apple TV
9:50:41.028 Add 2 18 local. _raop._tcp. 68644B1263CE@Apple TV
10:20:39.218 Rmv 0 18 local. _raop._tcp. 68644B1263CE@Apple TV
10:20:41.324 Add 2 18 local. _raop._tcp. 68644B1263CE@Apple TV