Subject: (ngtrans) Re: I-D ACTION:draft-ietf-ngtrans-bgp-tunnel-04.txt

From: Pekka Savola <[email-masked]>
Date: Fri, 8 Feb 2002 17:24:45 +0200 (EET)

On Tue, 15 Jan 2002 [email-masked] wrote:
> 	Title		: Connecting IPv6 Domains across IPv4 Clouds with BGP
> 	Author(s)	: J. De Clercq, G. Gastaud, T. Nguyen, 
>                           D. Ooms, S. Prevost, F. Le Faucheur
> 	Filename	: draft-ietf-ngtrans-bgp-tunnel-04.txt
> 	Pages		: 12
> 	Date		: 14-Jan-02

I've already commented on this, but I'll add a couple of more comments as
I read it a bit more.

4.1. "MP-BGP over IPv4" approach   

   Since MP-BGP requires that the BGP Next Hop is of the same address
   family as the NLRI, this IPv4 address needs to be embedded in an IPv6
   format. The IPv4-mapped IPv6 address is defined in [V6ADDR] as an
   "address type used to represent the addresses of IPv4 nodes as IPv6
   addresses", thus this precisely fits for the above purpose.  Encoding
   the routable IPv4 address into a IPv4-mapped IPv6 address allows the
   remote DS-BGP router to automatically tunnel data over the IPv4 cloud
   to the destination IPv6 island.  Any type of encapsulation can be
   used (IPv4, MPLS, GRE).

==> Note: the receiving end must have been configured beforehand to be 
recipient of such encapsulated packets, like autotunnel interface, GRE 
interfaces etc.

4.3. Characteristics Common To Both Approaches

   When the number of PEs is not too high, PEs MAY peer in a meshed
   fashion. Otherwise Route Reflectors MAY be used.

==> I find these statements (at least in CAPITALS) irrelevant to the 
specification.

8. Security considerations  

   This proposal can use the security features of BGP and any policy
   defined in the ISP domain.

==> rather weak.  E.g. using IPv4 encapsulation will most probably subject 
the router to all autotunnel considerations.

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords