DD-WRT: OLSR

General [edit] What is mesh networking?

Mesh networking is used to route data, voice and instructions between nodes (typically routers). A mesh network typically consists of 2 or (many) more nodes, which exchange information about their connection-status with each other (routing updates), so that every node knows, which path he has to take to reach any other node in the mesh. When a node wants to reach another node that is not directly connected, the traffic flows over other nodes, until the final node is reached (hopping) -each node that the traffic flows through is called a hop. [edit] Why mesh networking?

Mesh networks differ from other networks in that the component parts can all connect to each other via multiple hops. Mesh networks are self-healing: the network can still operate even when a node goes down or a connection drops. The result is a very reliable network. [edit] Benefits of mesh networking

   self organizing
   self-healing
   low system maintenance needed
   robust due dynamic route recalculation

[edit] Disadvantages of mesh networking

   additional network traffic

The exchange of routing information (routing updates) can produce a lot of traffic-overhead, also every device that takes part of a mesh must have enough cpu/ memory to have an overview of all other routers and how to reach them. (routing table). A full routing table can get very large - as seen in BGP-Routing: a full BGP table needs 2GB of memory (300.000 active routes). There is also a danger of routing-loops that can appear because of weak routing information. [edit] OLSR [edit] General

OLSR is a dynamic linkstate Protocol which collects link data and dynamically calculates the best routes within the network.

Links:

http://en.wikipedia.org/wiki/OLSR http://www.olsr.org

[edit] Parameters

General:

   IpVersion

   AllowNoInt

   Pollrate

   TcRedundancy

   MprCoverage

   LinkQualityFishEye

   LinkQualityWinSize

   LinkQualityDijkstraLimit

per Interface:

   HelloInterval

   HelloValidityTime

   TcInterval

   TcValidityTime

   MidInterval

   MidValidityTime

   HnaInterval

   HnaValidityTime

   LinkQualityMult

HNA4

IcpConnect

Plugins:

olsrd OLSR (Optimized Link State Routing) daemon olsrd-mod-dyn-gw-plain Dynamic internet gateway plain plugin olsrd-mod-bmf Basic multicast forwarding plugin, dependece: kmod-tun olsrd-mod-httpinfo Small informative web server plugin olsrd-mod-quagga Quagga plugin olsrd-mod-dyn-gw Dynamic internet gateway plugin olsrd-mod-txtinfo Small informative web server plugin olsrd-mod-nameservice Lightweight hostname resolver plugin olsrd-mod-dot-draw Dot topology information plugin olsrd-mod-mdns Multicast DNS plugin olsrd-mod-watchdog Watchdog plugin olsrd-mod-arprefresh Kernel ARP cache refresh plugin olsrd-mod-p2pd Peer to Peer Discovery plugin olsrd-mod-secure Message signing plugin to secure routing domain olsrd-mod-pud Position update plugin olsrd-mod-jsoninfo olsrd-mod-sgwdynspeed Select dynamic smart gateway based on gw speed

Sample config file:

DebugLevel 0 IpVersion 4 AllowNoInt yes Pollrate 0.1 TcRedundancy 2 MprCoverage 7 LinkQualityFishEye 1 LinkQualityWinSize 100 LinkQualityDijkstraLimit 0 7.0 LoadPlugin "olsrd_txtinfo.so.0.1" {

      PlParam "Accept" "127.0.0.1"

} Hna4 { } IpcConnect {

      MaxConnections  1
      Host            127.0.0.1
      Net 192.168.1.0 255.255.255.0

} LinkQualityLevel 2 UseHysteresis no Interface "eth1" {

      HelloInterval           5.0
      HelloValidityTime       90.0
      TcInterval              3.0
      TcValidityTime          270.0
      MidInterval             15.0
      MidValidityTime         270.0
      HnaInterval             15.0
      HnaValidityTime         90.0
      LinkQualityMult 10.100.2.5 0.5

} Interface "vlan1" {

      HelloInterval           5.0
      HelloValidityTime       90.0
      TcInterval              3.0
      TcValidityTime          270.0
      MidInterval             15.0
      MidValidityTime         270.0
      HnaInterval             15.0
      HnaValidityTime         90.0
      LinkQualityMult 10.100.2.5 0.5

}

[edit] Setup [edit] DD-WRT > v.23 SP3

You always can check the OLSRD status on the daemons web gui:

http://yourip:8080

   enable your prefered networking mode. OLSR can run on any interface (lan or wifi).

Try the following steps to get OLSR running: [edit] OLSR on WiFi

Under Wireless -> Basic Settings

   connect your devices with the preferred WiFi mode (WDS, adhoc, etc)
   set your wlan mode (b,g,mixed...)
   set your SSID
   set your channel

Before you go on test that the link is working, that the devices are connected and can reach each other.

   unbridge the wlan on the wireless page
   set an ip from a different network than the router uses already
   set the network mask (e.g. to 255.255.255.0 for a /24 network)
   set your preferred encryption

[edit] setup OLSR

Under Setup -> Advanced Routing

   set Operating Mode to OLSR
   keep the basic olsr settings. they are ok for the first tests
   add the correct wlan interface to olsr dependend on your wifi chip vendor and platform (e.g. on atheros wifi based systems its athX, on broadcom its mostly eth0, on ralink its raX)
   keep the interface settings for testing

[edit] Enabling NAT routing

In Gateway mode the router performs NAT, while in other modes it doesn't. When you switch the Advanced Routing Operating Mode to OLSR Router, it turns off NAT. Here is how to turn the NAT back on, assuming you followed the instructions on unbridging the wlan. You must change the interfaces according to your system.

Under Administration -> Commands paste the script below into Commands and click "Save Firewall" Do this on each device.

iptables -t nat -A POSTROUTING -o $(nvram get wan_ifname) -j MASQUERADE iptables -t nat -A POSTROUTING -o $(nvram get wl0_ifname) -s $(nvram get eth1_ipaddr)/$(nvram get eth1_netmask) -d $(nvram get eth1_ipaddr)/$(nvram get eth1_netmask) -j MASQUERADE iptables -t nat -A POSTROUTING -o $(nvram get lan_ifname) -s $(nvram get lan_ipaddr)/$(nvram get lan_netmask) -d $(nvram get lan_ipaddr)/$(nvram get lan_netmask) -j MASQUERADE

DD-WRT: OLSR

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