4. Test bed

4.2.1. Fully functional IPv6 network

Before we can start testing mobile IP, we need a fully functional IPv6 network. All the nodes should be able to ping each other. This is a crucial part. If, for example, AR is not able to ping HA, then there will be no binding update.

I will give a brief instruction to get our network up and running using IPv6. For more info on setting up an IPv6 network, you can read Peter Bieringer's excellent Linux IPv6 HOWTO.

I've turned off encryption for simplicity - NOTE that you should ALWAYS use encryption when dealing with wireless networks!

Also note that the different wireless networks have different ESSIDs!

1. MN: The Mobile Node has one wireless interface. Forwarding should be turned off, but should accept autoconf and ra's:

   # iwconfig eth0 mode ad-hoc essid homenet enc off # ifconfig eth0 inet6 add fec0:106:2700::4/64 # echo "0" > /proc/sys/net/ipv6/conf/eth0/forwarding # echo "1" > /proc/sys/net/ipv6/conf/eth0/autoconf # echo "1" > /proc/sys/net/ipv6/conf/eth0/accept_ra # echo "1" > /proc/sys/net/ipv6/conf/eth0/accept_redirects # /etc/init.d/mobile-ipv6 start # ip route add ::/0 via fec0:106:2700::1

2. HA: The Home Agent has one wireless interface. It should have forwarding turned on because it uses normal routing to deliver packets captured from a physical interface to the virtual tunnel interface. Note: You must add a default route or else HA will have problem contacting the MN. One possible solution is to have HA as the default router of the home network.

   # iwconfig eth0 mode ad-hoc essid homenet enc off # ifconfig eth0 inet6 add fec0:106:2700::2/64 # echo "1" > /proc/sys/net/ipv6/conf/eth0/forwarding # echo "0" > /proc/sys/net/ipv6/conf/eth0/autoconf # echo "0" > /proc/sys/net/ipv6/conf/eth0/accept_ra # echo "0" > /proc/sys/net/ipv6/conf/eth0/accept_redirects # ip route add ::/0 via fec0:106:2700::1 # /etc/init.d/mobile-ipv6 start

3. R: The (home) Router has two interfaces, one wireless and one line. The Router must have forwarding turned on.

   # ifconfig eth0 inet6 add fec0:106:2300::2/64 # iwconfig eth1 mode ad-hoc essid homenet enc off # ifconfig eth1 inet6 add fec0:106:2700::1/64 # echo "1" > /proc/sys/net/ipv6/conf/all/forwarding # echo "0" > /proc/sys/net/ipv6/conf/all/autoconf # echo "0" > /proc/sys/net/ipv6/conf/all/accept_ra # echo "0" > /proc/sys/net/ipv6/conf/all/accept_redirects # ip route add fec0:106:1100::/64 via fec0:106:2300::1

4. AR: The Access Router (on a foreign network) also has two interfaces, one wireless and one line. Forwarding must be turned on.

   # ifconfig eth0 inet6 add fec0:106:2300::1/64 # iwconfig eth1 mode ad-hoc essid visitnet enc off # ifconfig eth1 inet6 add fec0:106:1100::1/64 # echo "1" > /proc/sys/net/ipv6/conf/all/forwarding # echo "0" > /proc/sys/net/ipv6/conf/all/autoconf # echo "0" > /proc/sys/net/ipv6/conf/all/accept_ra # echo "0" > /proc/sys/net/ipv6/conf/all/accept_redirects # ip route add fec0:106:2700::/64 via fec0:106:2300::2

Instead of modifying proc variables, you can use sysctl.

Note: We are setting static routes on our test-bed. You should now be able to ping all the hosts from every host.

4.2.2. Configuring radvd on AR

When MN comes to a new network, it does a link-local address configuration, going to the next phase if that succeeds. I'll let [RFC2462] (IPv6 Stateless Address Autoconfiguration) describe the next phase:

"The next phase of autoconfiguration involves obtaining a Router Advertisement or determining that no routers are present. If routers are present, they will send Router Advertisements that specify what sort of autoconfiguration a host should do. If no routers are present, stateful autoconfiguration should be invoked."

"Routers send Router Advertisements periodically, but the delay between successive advertisements will generally be longer than a host performing autoconfiguration will want to wait. To obtain an advertisement quickly, a host sends one or more Router Solicitations to the all-routers multicast group." --- page 8

This is where we use RADVD.

Read [RFC2462] more more details concerning IPv6 Stateless Address Autoconfiguration.

We'll configure RADVD on AR's wireless interface. The radvd.conf file should contain this:

    # cat /etc/radvd.conf
    interface eth1                     
    {                                   
          AdvSendAdvert on;
          AdvIntervalOpt on;            

          MinRtrAdvInterval 3;         
          MaxRtrAdvInterval 10;        
          AdvHomeAgentFlag off;        

          prefix fec0:106:1100::/64    
          {                           
              AdvOnLink on;           
              AdvAutonomous on;        
              AdvRouterAddr on;       
          };                         
    }; 
    

We then start it:

    # /etc/init.d/radvd start
    

You should now be able to use radvdump to see that the radvd messages really are being sent periodically:

    # radvdump
    Router advertisement from fe80::202:2dff:fe54:d1b2 (hoplimit 255)
    Received by interface eth1
          # Note: {Min,Max}RtrAdvInterval cannot be obtained with radvdump
          AdvCurHopLimit: 64
          AdvManagedFlag: off
          AdvOtherConfigFlag: off
          AdvHomeAgentFlag: off
          AdvReachableTime: 0
          AdvRetransTimer: 0
          Prefix fec0:106:1100::/64
                  AdvValidLifetime: 2592000
                  AdvPreferredLifetime: 604800
                  AdvOnLink: on
                  AdvAutonomous: on
                  AdvRouterAddr: off
          AdvSourceLLAddress: 00 02 2D 54 D1 B2
    

4.2.3. Configuring radvd on HA

To enable the MN to know when it's home, HA should also be sending out RAs. We should therefore enable RADVD on the HA as well. The /etc/radvd.conf file should contain:

     # cat /etc/radvd.conf
     interface eth1
     {
        AdvSendAdvert on;
        MaxRtrAdvInterval 3;
        MinRtrAdvInterval 1;    
        AdvIntervalOpt off;
        AdvHomeAgentFlag on;
        HomeAgentLifetime 10000;
        HomeAgentPreference 20;
        AdvHomeAgentInfo on;
        prefix fec0:106:2700::2/64
        {
          AdvRouterAddr on;
          AdvOnLink on;
          AdvAutonomous on;
          AdvPreferredLifetime 10000;
          AdvValidLifetime 12000;
        };
      };
      

To be completed.

4.2.4. Configuring MIPv6

The last configuration is MIPv6 settings in network-mip6.conf. In RedHat the file is found under /etc/sysconfig/network-mip6.conf. The file should be pretty self-explanatory.

     # cat /etc/sysconfig/network-mip6.conf
     
     # Home Agent configuration file
     FUNCTIONALITY=ha
     DEBUGLEVEL=1
     MIN_TUNNEL_NR=1
     MAX_TUNNEL_NR=5
     TUNNEL_SITELOCAL=yes
  
     # cat /etc/sysconfig/network-mip6.conf

     # Mobile Node configuration file
     FUNCTIONALITY=mn
     DEBUGLEVEL=1
     TUNNEL_SITELOCAL=yes
     MIN_TUNNEL_NR=1
     MAX_TUNNEL_NR=3
     HOMEDEV=mip6mnha1     
     HOMEADDRESS=fec0:106:2700::4/64  # MN home adress
     HOMEAGENT=fec0:106:2700::2/64    # HA's address
    

Next, start mobile-IP:

    # /etc/init.d/mobile-ip6 start
    

You can verify that it started by doing:

    # ifconfig
    

If a tunnel comes up ip6tnl1, mobile-ip6 is started.