[files/nodes.conf] routers now run ISIS _and_ OSPF as IGPs
[files/nodes.conf] routers now run ISIS _and_ OSPF as IGPs

* background: quagga's ISIS implementation is not (yet) able to redistribute
  routes to ISIS which means that it is currently not possible to create multi
  AS networks using only ISIS and BGP.

* this is a very dirty hack to work-around this issue (probably only for a very
  few use-cases):
  When using OSPF as IGP and BGP as EGP, quagga redistributes learnt routes from
  one routing protocol to the other  (i.e., after redistribution, OSPF knows
  about external routes learnt through BGP and BGP knows about internal routes
  learnt through OSPF).
  For IS-IS the route redistribution feature is not yet implemented.
  Running BGP together with OSPF ensures that any routing protocol agnostic
  service is able to operate correctly within the entire network.
  Services that depend on the existence of IS-IS are able to join the (AS-)local
  IS-IS network and through, it will learn the local AS topology.
  It is up to the user to decide whether this approach suffices her needs.

Signed-off-by: Robert Wuttke <12e9293ec6b30c7fa8a0926af42807e929c1684f@benocs.com>

Benocs/core,Benocs/core,Benocs/core,Benocs/core,Benocs/core