Route IPv4 via Babel

[spolack]

In order to get rid of olsrd to replace it with babel we should find a way, to not interrupt Routing for nodes which are not yet upgraded to avoid taking them down.

Proposed procedure:

1. Deploy Routing Changes on all core routers running babel - All which are in bbb-configs. Implement IPv4 Route Policy to prefer babel routes #965

   • Add new Routing Tables to avoid babel routes compete with olsrd, which could lead to routing loops. We have to ensure that the routes get installed only in the appropriate tables, never in the default/main.

     babel-default # Contains default routes from babel
     babel-ff # Contains freifunk routes (hna) from babel
     olsr-default # Contains default routes from olsr
     olsr-ff #  Contains freifunk routes (hna) from olsr
     

   • Setup routing policy in following order:

     babel-ff -> olsrd-ff -> babel-default -> olsrd-default
     

   With these changes in place we have ensured that babeld and olsrd routes never compete and babel is prefered whenever a route is there, but if not it is routed using olsr.

2. Enforce similar routing changes to gateways, but keep babel-default and olsr-default out of the routing policy, because they will never be used

3. Announce default route from gateway into babel. From this moment on all traffic going towards internet from BBB is using babels routes

4. Announce HNA from all nodes into babel

5. olsrd is unused from this moment on, but still in place to carry routes to non-babel islands connected to BBB

[spolack]

In order to clean up the mess of having many routing daemons i ran a PoC to verify if bird2 can be used as drop-in replacement replacing babel entirely. #995

[spolack]

Seems the test results were promising.

Lets deploy that on our main hub sites across the backbone.

• segen-core
• sama-core
• magda-core
• spitta13-core
• liese-21-core
• q216-core (private location)
• zwingli-core
• vaterhaus-core
• emma-core
• rhnk-core
• klunker-core
• philmel-core (PR pending philmel: cleanup #893)
• rhxb-core
• simeon-core
• flughafen-core
• teufelsberg-core (PR pending Teufelsberg: New APs #1035)
• mela-core
• chris-core

Once this is done we can start advertising the IPv4 default route via bird!! :)