RE: 3gpp-analysis document and automatic tunneling

[Hesham Soliman <H.Soliman@flarion.com>]

Pekka, 

I'm very confused, please see below.


 > > In particular, I feel this is an issue about IGP/BGP 
 > tunneling.  It is
 > > possible such methods could be used -- if the network is 
 > built just so --
 > > but that's entirely different thing from whether they're a 
 > required or
 > > even a recommended solution ("we have a hammer, now let's 
 > go find the
 > > nails").
 > > 
 > >   JW: Well, I don't think we can give unambiguous 
 > recommendations. It is
 > > much better to discuss different solution alternatives. 
 > Anyway, we can't
 > > require any solutions to be used by operators. We had some 
 > discussion
 > > with other authors (especially Karim) how to edit the 
 > text. One point
 > > that was brough up in the discussion was redundancy. 
 > Static tunnels on
 > > their own don't give a solution if a route goes down. 
 > Instead, EGP/IGP
 > > mechanisms support this. Say that I have multiple tunnels 
 > to two router
 > > endpoints connected to the same network. If one goes down 
 > I would like
 > > to start tunnelling to the other. Do you have any comments on this?
 > 
 > If an operator wishes redundancy, he will run routing 
 > protocol(s) on top
 > of his network infrastructure. This would be the case e.g. 
 > if the IPv6
 > network was run on top of static ATM PVC's.
 > 
 > In the case of IPv6-over-IPv4, this is often not (as) 
 > necessary 

=> Why is it not necesary in this case? I feel like
I'm missing something.

   (but there
 > are some other failure modes in some scenarios), if the IPv4
 > infrastructure is redundant and there is an IPv4 routing protocol to
 > ensure the reachability.  

=> If you're tunnel end point is a certain IPv4 address 
and that address is statically configured I don't 
understand the relevance of the IPv4 routing infrastructure
and potential redudancy. If you always tunnel to B and 
B crashes (B was manually configured) what can IPv4
routing do here ?


  On the other hand, if you cannot 
 > rely on the
 > IPv4 infrastructure, you have to run the routing protocol anyway.

=> Don't see the relevance to the point. Am I missing
a few things :( ?

 > 
 > It seems to me that IGP/EGP mechanisms provide little added 
 > value here --
 > except if you have a very large number of IPv6-enabled 
 > routers you wish to
 > connect in a full-mesh manner, and manual configuration
 > would be a chore.  
 > Such operators have a lot of other chores too, as managing the other
 > aspects of the routers is not simple either.

=> What other choices do they have?

 > 
 > I've having difficulty picturing that particular deployment (a lot of
 > routers, dense mesh instead of some hierarchy, etc.) to be a 
 > requirement.

=> This is the case in many planned networks today.

Hesham