southampton open wireless network the topology talk

www.sown.org.uk

Southampton Open Wireless NetworkThe Topology Talk

www.sown.org.uk

Southampton Open Wireless NetworkOutline

• The SOWN VLAN

• The Topology Schematic

• Community Area Network (CAN)

• Parts of SOWN– Core Network– Campus Nodes– sown[at]home

• IPv4 addressing on SOWN

• IPv6 addressing on SOWN

www.sown.org.uk

Southampton Open Wireless NetworkVLANs

• A VLAN is a Virtual LAN– Think of a set of computers connected to a single switch– A VLAN switch emulates many dumb switches and you

spread a LAN across many VLAN switches transparently

• SOWN uses a campus wide VLAN– Servers in 3 different buildings– VLAN connected nodes on 1 of those + 1 other (SUSU)

www.sown.org.uk

Southampton Open Wireless NetworkThe Topology (1)

Where’s the SOWN VLAN?

www.sown.org.uk

Southampton Open Wireless NetworkSOWN CAN

• SOWN is a Community Area Network (CAN)

• A CAN is a wide area LAN where all users are connected to the SOWN LAN no matter on their location.

• Users of the network can connect to each other directly

• Has the advantage that you don’t need NAT internally and can offer services such as VOIP and LAN gaming

www.sown.org.uk

Southampton Open Wireless NetworkSOWN Nodes

www.sown.org.uk

Southampton Open Wireless NetworkCampus Nodes

• A wireless hotspot providing connectivity to the SOWN CAN

• High power nodes with large coverage areas

• Have direct connection to the sown servers for internet connection and authentication

www.sown.org.uk

Southampton Open Wireless Networksown[at]home Nodes

• Plug’n’Play wireless access points to allow SOWN access to be broadcast from users house with the minimum of fuss• Just plug it in to a free network port on your router and switch on!

• Makes use of home ADSL line for internet access• Tunnels are set up to sown-vpn so SOWN network access is granted. • User authentication is passed down the tunnel to sown-auth• Nodes are made by Meraki, but run with our own firmware based on

OpenWRT (linux distribution for home routers) which is configured to work with SOWN.

www.sown.org.uk

Southampton Open Wireless NetworkCore Servers

www.sown.org.uk

Southampton Open Wireless Networknat.sown.org.uk

• Gateway between sown and internet.

• Acts as a Network Address Translator (IPv4) and Firewall for IPv4 traffic.

• NAT is required due to the lack of free availability of global IPv4 addresses.

• (also runs the sown-bot on our irc channel)

www.sown.org.uk

Southampton Open Wireless Networkauth.sown.org.uk

• The Authentication Server and SOWN Control Server

• When users join a SOWN node this server hosts the captive portal pages which enable login

• Server is peered with ECS and Eduroam authentication servers

• Auth is the main server on the network and can also control firmware updates being sent to the nodes

www.sown.org.uk

Southampton Open Wireless Networkvpn.sown.org.uk

• Hosts connections between the SOWN VLAN and the sown[at]home nodes

• Home nodes establish a tunnel to this server when they are bought online

• Runs Nagios to monitor the status of the SOWN network as it is at the most central point of the network

www.sown.org.uk

Southampton Open Wireless Networkdev.sown.org.uk

• The SOWN development server

• Allows testing of new services

• A place from which new users can experiment with the SOWN network

• Acts as the fallover VPN server.

www.sown.org.uk

Southampton Open Wireless NetworkThe Topology (2)

When someone joins a node what happens and how do they get on the internet?