RE: [Mip6] [issue94] fixing encapsulation mechanism in IPv4 network

["Hesham Soliman" <Hesham at elevatemobile.com>]

Keiichi, 

We will have a formal concensus call on this but let's here a few opinions
first. My opinion below:
 

 > New submission from Keiichi SHIMA <keiichi at iijlab.net>:
 > 
 > The current DSMIPv6 draft specifies two encapsulation 
 > formats, one is the IPv4 encap format, the other is 
 > UDPv4 encap format.  The default encapsulation format is the 
 > IPv4 format, and if the HA explicitly 
 > specifies to change the encapsulation format to the UDPv4 
 > format if there is a NAT box between the HA 
 > and the MN.  Because of this specification, HA and MN have 
 > to support both encapsulation formats and 
 > have to change the format dynamically, that may increase the 
 > hurdle for implementors and may cause 
 > complexity in interoperability.
 > 
 > Isn't it possible to fix the encapsulation format to one of 
 > these mechanisms described in the draft?

=> So basically you're asking for UDP-only tunnelling. As I mentioned in a
previous email, this a tradeoff between reducing the implementer's work and
reducing redundant bits on the wire. I think it makes more sense to reduce
additional bits on the wire. The UDP tunnel is redundant if no NAT were
detected. So your suggestion amounts to removing NAT detection and always
using UDP tunnels. I think this is inefficient, especially when the cost of
switching between the UDP tunnel and IP n IP is very small (from an
implementation point of view). 

Hesham

 > 
 > ----------
 > category: Technical
 > draft: draft-ietf-mip6-nemo-v4traversal
 > messages: 338
 > nosy: keiichi
 > priority: May fix
 > status: No discussion
 > title: fixing encapsulation mechanism in IPv4 network
 > 
 > _________________________________________________
 > Mip6 issue tracker <tracker-mip6 at mip4.org>
 > <http://www.mip4.org/issues/tracker/mip6/issue94>
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 > Mip6 at ietf.org
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 > 



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