Thank you for your speedy reply!
Right to clarify - the network topolgy is a star configuration, so there are no possible loops... no branches have an alternate path to follow at this stage.
Right - now to try and give more info:
The entire network (routers) are assigned IP addresses on the bridge (all backbone interfaces and WDS on wireless are assigned to the bridge, AP's are not) in the range of 10.0.96.1 - 10.0.103.254, with a subnet mask of /21.
We have two main areas, where routers are assigned 10.0.101.xxx and 10.0.100.xxx
We use RADIUS authentication over PPPoE to connect clients through the AP's, which have no IP assigned to them (not bridged).
The gateway address is 10.0.100.254, and the RADIUS address is 10.0.100.1
If we assign addresses on the RADIUS manager in the 10.0.100.xxx range, all is well, but if we assign 10.0.101.xxx ip's then they can connect initally, but after disconnecting and trying again, they either cannot access the RADIUS, or they can, but have no Internet connectivity.
Now, if I connect via PPPoE, being assigned a 10.0.100.xxx IP, then I sometimes can access the 10.0.101.xxx routers, and after some time (short time) I can no longer access these routers, and vice-versa.
Someimes, if I clear the ARP table on the router I am connecting to, then I can access these IP's, but doing this does not seem to be consistant.
Examples of the config:
/ interface bridge
add name="br0" arp=proxy-arp disabled=no
/ interface bridge port
add interface=ether1 bridge=br0
add interface=wlan1 bridge=br0
/ ip address
/ ip dns
set primary-dns=10.0.100.254 secondary-dns=0.0.0.0 allow-remote-requests=yes
/ ip route
add dst-address=0.0.0.0/0 gateway=10.0.100.254 \
/ ppp profile
set default local-address=10.0.101.53 remote-address=0.0.0.0 \
use-compression=default use-vj-compression=default use-encryption=yes \
only-one=no change-tcp-mss=yes dns-server=10.0.100.254
add service=ppp,wireless address=10.0.100.1 \
Thanks for your time!