The idea is for the AP900 to be transparent, as far as the 2860n is concerned, in normal operations. In other words, it needs to act like a Vigor 130 - at a lower level than IP, not as an IP Router where it needs a valid IP address. So the 2860n initial starts out with only a 192.168.100.254 address on WAN2, which is used to connect to the AP900 so it can be configured to connect to the Hotel Access Point. At that point, it acts more like a bridge - allowing DHCP requests from the 2860n straight-thru, so that the 2860n (and not the AP900) is the client on the Hotel network.

However...

I don't know which manual I've been reading, but the AP900 doesn't seem to have the required STA (station) mode that many (very cheap) portable Wifi devices have (eg TP-Link WR702n ).

Oops. :? :oops:

Re-reading the AP900 manual (god knows what I was reading, the first time round!), I note the following (section 3.8.7 Universal Repeater)

The access point can act as a wireless repeater: it can be station and AP at the same time. It can use Station function to connect to a Root AP and use AP function to serve all wireless stations within its coverage

So, maybe (just maybe), configuring the AP900 for Universal Repeater mode (and then not filling in any AP details), is the way to go. I'm living in hope that with no AP configured, it will just pass traffic between its LAN and the upstream Hotel AP.

Just given it a go and looks like it does require an IP adress assignment for the LAN. Surely though I should be good with this setup whereby the MAC address of the AP900's Wireless Radio can still be cloned to that of my phone and work as a repeater?

Time will tell

Out of curiosity, do the Hotels you frequent no longer provide an RJ45 socket on the wall?

(My 'other half' used to roam China, with the aforementioned TP-Link mini-AP plugged in, to provide a home-from-home SSID. (She always reckoned that Chinese hotel WIFI was virtually unusable)

Sadly one of the places we stay don't seem to offer an Ethernet socket option in the room as that would make the whole process a lot simpler!

Reminds me of the days when I carried a bag full of telephone socket adapters to plug in my Psion Gold Card modem..... :lol:

That's going back a fair bit :lol: