I have a plan to a very big WISP , its for a big city , some millions of population , 1000's of clients , I should install 10's of towers , but i have many options of what would be the network design ..
the prefered design is to make a centeral everything ; hotspot , radius , billing server , etc .. in the centeral location all these servers connected to the main tower which has the points of backhaul , other towers will be connected to this tower , it will be a tree of towers ..
is it a good idea to make it central network ? the user may connect to a tower is far by >15km from the centeral tower , he will connect to a tower which may the tower number 4 or 5 after the centeral ..
all nodes on towers are only bridges , no firewall , just passing the traffic ..
is there better idea ? any modification to this idea ? suggestions ?

I would build a routed ring topology with 2 exitpoints
and avoid single points of failure.

Stefan

My thoughts:
-Route as many locations as possible. This will make your backhauls much more efficient.
-Use /29 or similiar small subnets for the backhauls. This will help with broadcast traffic.
-Have redundant links into each POP as you can. You can take advantage of OSPF. In essence you have two rings around your network. Not always practical, but where you can it's worth it.

Why no firewall? Traffic shaping and priority can make a healthy network.

Justin

Something that big, it is impossible to have the reliable hardware to centralize hotspot. As others have said, route traffic to the towers. Thousands of users on a bridged network is real close to disaster and you'd be lucky if it worked. You'd probably want a subnet per AP. You probably want commercial ISP specific radio equipment (Alvarion, Canopy, Trango, and others..) Otherwise you will spend all your time tinkering or tending to a small number of customers instead of hooking more up.

good replys thank to all , as a conclusion from wht has been said , a central hotspot is a bad idea if using mikrotik !!!

an all bridged network is also bad, especially once you get above a couple of hundred customers. Central point of failure is bad too.

Hi everyone.
Thanks for very good answers. Last few weeks I am braking my brain how to design make the best toplogy. One of my ideas was to make somethink like samsoft08 said: make all bridge MT-s with one central point where users will authenticate. And now that ideas is definitly off my topic.

Now I wonder, will radius work good with all that routet network because every user will authenticate at his access point and every router will have same ip of radius server?

Regards

is the only disadvantage of bridged network is that we depend on a single central point , when it failed all network failed ?
or there are other disadvantages ?
ok , lets say we just bridge the nodes AP , installing at every node a x86-RouterOs which will work as a hotspot , cache server and firewall for this node ,but this hotspot must authinticate the users (connected to this node) through the central radius/billing server ..
so , each node will be like this :
from central (or another node ) =====AP client ----- x86-RouterOs------AP===users
how is this ?
regarding that we are talking about > 2000 online users !!!!

If you're going >2000 clients then a backup/secondary radius server is a good idea also.

Why not do some internal bgp to 2 central points both with links back to your datacentre/office where the radius+database server are located.
That way you aren't relying on a single link to your servers, nor relying on a single server.

there is presentation on this topic in last MUM (Egypt MUM)
i think it will be very helpful
here is PDF link http://mum.mikrotik.com/presentations/EG07/lutz_kleeman.pdf
and this is video version http://www.tiktube.com/2007/11/30/mum-eg07-lutz-kleeman-wisp-in-de/

from your replys , i found that is the most important isuue for you is the redundancy ..ok i agree ..
about EOIP as I read , its less than wds in speed , so thats mean i'll loose more throughput when my network will be large with many nodes ..
how can I route the backhaul ? i need to use centeral hotspot server , is it possible ?
wht about if i use a hotspot server at each node ? can all these servers get authontication by the centeral radius server ?

so long as the hotspots have their correct routes or routing setup (be it static or dynamic via ospf, bgp or mme) then they'll be able to find the central server (and provided you've set it up correctly) authenticate against it.

whether you then put public or private ranges behind each hotspot device is up to you.

If I were you I wouldn't even attempt to use EOIP or WDS on the links (apart from at an actuall location) all links that make up your backbone network should be bridged or point to mutipoint connections. If the backhaul points aren't moving then theres no reason WDS would be any better. If you're using WDS on the client side then that would help them move around as needed.