Subject: New BOF in Internet Area - TC

From: [email-masked]
Date: Fri, 04 Mar 2005 02:26:52 -0500

Tunneling Configuration BOF (tc)

Monday, March 7 at 1530-1730
============================

CHAIRS: Alain Durand <[email-masked]>
	Thomas Narten <[email-masked]> 

AGENDA:

Problem space:
 - Administrativia (2 min) 
   Alain Durand  & Thomas Narten
 - Problem statement (10 min) 
   Thomas Narten
 - v6ops initial "combine" goals (10 min) 
   Jordi
   draft-palet-v6tc-goals-tunneling-00.txt
 - Use of the configuration protocol outside of the context of IPv6
   tunneling (10 min), 
   TBD
 - NAT traversial issues (10 min) 
   Florent Parent
 - Is Tunnel End point discovery required? (10 min) 
   Alain Durand / Thomas Narten

Solution space:
 - Existing protocol analysis (20 min) 
   Florent Parent & Pekka Savola
   draft-blanchet-t-v6ops-tunnelbroker-tsp-01.txt
   draft-parent-v6tc-protocol-exploration-01.txt
 - Tunnel end-point discovery analysis (10 min) 
   Pekka Savola
   draft-palet-v6ops-tun-auto-disc-03.txt
Open discussion (30 minutes)
 - Should we do something specific for IP in IP tunneling or
   something more generic that will work with any kind of
   encapsulation (GRE, MPLS,...)
 - Should this wg to be address the tunnel end point discovery part of
   the problem?
 - Should we cover the case of the set-up of a mesh of multiple tunnel ?

DESCRIPTION
===========
ISPs will likely deploy IPv6 incrementally, meaning that parts, rather
than all of their networks will support native IPv6 service. They will
need a way to provide IPv6 service to customers without requiring that
native IPv6 service be provided on the access link.  Automatic transition 
mechanisms like 6to4, teredo do not really leverage the infrastructure 
the ISP had put in place and offer little insight on how to gradually 
introduce native IPv6 in the access network.  Configured tunnels are 
better suited for the job, and a number of deployments have been 
undertaken using the tunnel broker approach. However, the lack of 
standard on how to configure those tunnels remains a serious obstacle 
and manual configuration of all the parameters is a significant burden 
for typical customers.

ISP assumptions:

It is assumed that the ISP has upgraded its core network and has
global IPv6 connectivity. It is also assumed that the ISP has obtained
global address space (that it will delegate to its customers), either
from an RIR or an upstream ISP.  They key point is that the ISP does
not (yet) provide native IPv6 access to all of its customers, but does
want to provide an IPv6-over-IPv4 tunneling service. It is also
assumed that large ISPs will have multiple POPs, and roaming customers
will want to use a tunnel service topologically close to the current
POP, rather than always using the same one.

Access media assumptions:

No assumptions are made on the access network. They will have high or
low bandwidth, high or low latency, high or low access cost, and there
will be more or less secure. Especially in the case of wireless access
network, confidentiality of the data cannot always be guaranteed. Address 
spoofing may or may not be a problem.  Although those environment vary 
widely, it is expected that a single configuration protocol with a number 
of options can be designed to accommodate all the different cases.

Customer assumptions:

Customers connecting with IPv6 to their ISP can have multiple
configurations.
The most common topologies expected to be encountered are:

  - a single node, directly attached to the ISP access network
  - a router, directly attached to the ISP access network
  - a router, behind an unmodifiable IPv4-only customer owned NAT

The IPv4 addresses of the customer may change over time and be dynamically 
allocated.  In the case of NAT environment, both the internal and the 
external addresses may be dynamically allocated.  Another case to consider 
in the "roaming" user within its home ISP network. When the customer is 
roaming within the ISP network(s), this is not really different than having 
a dynamic IPv4 address, except that the "nearest" ISP tunnel end point to 
use may be different.  When the customer is roaming in another ISP network 
that does not offer IPv6 service, the "home" ISP may be willing to still 
offer tunneling service, however the security implications and the tunnel 
end point discovery mechanism to use will be different.

Work items:

A "generic" tunnel setup protocol. The key requirement is to allow the
creation of a tunnel for sending IPv6 over IPv4. In order to setup a
tunnel, some negotiation may be needed in order to determine such
properties as the encapsulation (e.g., GRE, IPv6-over-IPv4, etc.), MTU
parameters, authentication and/or security properites, etc.  For
reasons of efficiency over very high latency networks, minimizing the
number of packet exchanges is desirable.

This group will not create new tunneling encapsulations. Moreover, it
will reuse the work of other WGs rather than inventing unneeded
mechanism. For example, IPsec can be used to create tunnels. The setup
protocol could determine that an IPsec tunnel is needed, and then rely
on IKE (as specified elsewhere) to setup up the appropriate tunnel.
--------------------------------------------
A key question the BOF should answer is if the tunnel set-up protocol
should be limited to IP in IP tunnel (with a focus on IPv6 in IPv4) or
if it should be extended to other types of encapsulation, like GRE,
MPLS,...
--------------------------------------------
Another possible work item is a way for an ISP to indicate that it is
offering tunnel services to its direct customers. This is also known
as tunnel end-point discovery.
--------------------------------------------
The BOF should answer is if this second work items should be covered
by the same wg or not.
--------------------------------------------

Focus:

This work is not about creating a new transition mechanism, but to
offer a standardized way to configure tunnels.

Some of the issues initially explored are:
	- Do we want to focus on IP in IP tunnels or extend to GRE, MPLS,...
	- Do we want to address the tunnel end point discovery problem?
	- Could we live with UDP encapsulation always on?
	- Do we need mutual authentication? How strong should this be?
	- Should some of this authentication mechanism "follow-on" atfer 
          the tunnel set-up phase
	  has finished?
	- Can we have separate channels, one for configuration and one for
	  the tunneled traffic or should we maintain only one channel to
	  help traverse NAT?
	- Should we embed some kind of signaling in the tunnel channel?
	- How much of the wheel are we going to re-invent?
  	  e.g. if we define a new packet exchange and there is a goal
	  to minimize the total number of RTT needed, there is a temptation
	  to piggy-back configuration information in this protocol that could
	  be over wise obtained via DHCP...

List of documents to be used originally as input:

http://www.v6ops.euro6ix.net/ietf/draft-suryanarayanan-v6ops-zeroconf-reqs-01.txt
draft-nielsen-v6ops-3GPP-zeroconf-goals-00.txt
draft-ietf-v6ops-assisted-tunneling-requirements-01.txt
draft-palet-v6tc-goals-tunneling-00.txt
draft-blanchet-t-v6ops-tunnelbroker-tsp-01.txt
draft-parent-v6tc-protocol-exploration-00.txt
draft-parent-v6tc-protocol-exploration-01.txt
draft-palet-v6ops-tun-auto-disc-03.txt

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