MONDAY, March 23, 2009
0900-1130 Morning Session I
BOF Introduction -- Chairs (10 minutes)
-- Blue sheets, Jabber scribe, minute takers
-- BOF goals (e.g. non-working group forming)
Problem Space
9:10  9:25 AM, Issues with addressing sharing approaches,
M. Ford & P. Levis (15 minutes)

9:25 AM  9:30 AM Discussion

9:30 AM  9:40 AM, Shara Scenarios
M. Bagnulo & C. Jacquenet (10 minutes)

9:40 AM  9:45 AM Discussion
9:45 AM  10:10 AM Solution space for address sharing, R. Bush,
G. Bajko, M. Boucadair, P. Levis, Olaf and T. Savolainen (30 minutes)

10:10 AM  10:15 AM, SAM, R.Despres (5 minutes)

10:15 AM  10:25 AM Discussion
10:25  10:35 AM, Benefits of NAT avoidance,
T. Savolainen (10 minutes)

10:35 AM  10:45 AM, Implications of SHARA on
Operations & Mgmt, A. Durand (10 minutes)

10:45 AM  10:55 AM, Security Implications,
P. Levis (10 min)

10:55 AM  11:05 AM Discussion
Open Questions
What are we missing?
Geoff Huston (10 minutes)
Discussion -- All (10 minutes)

Next steps
AD, Chairs  (5 min)

Sharing IPv4 Addresses (SHARA) BOF

In the current Internet, it is fairly common for ISPs to provision
their subscribers with a single public IPv4 address and for those
subscribers to use NAT technology to allow multiple machines in
their networks to access the Internet. This setup essentially
requires one public IPv4 address per subscriber. As the IPv4 free
address pool becomes depleted, it seems likely that  ISPs will not
have enough public IPv4 addresses to assign one address per
subscriber. When that happens, multiple subscriber networks will
have to share a single public IPv4 address. Multiple approaches
have been proposed in order to implement the sharing of public
IPv4 addresses, some of which are described in section 2.1 of

The goal of this BOF is to discuss and gain understanding of a
particular family of solutions, the Port-Extended IPv4 addressing
approaches, some of which are described in section 2.1.2 of
draft-arkko-townsley-coexistence-00. This family of solutions,
essentially assigns a public IP address and a port range to
each subscriber and relies on some form of port range routing
capability within the ISP network. The result is that each
subscriber still obtains at least a part of a public IP address
and retains some of the capabilities of the current configuration.

During the BOF we intend to discuss the following items:
- Problem characterization: We need to understand what is
exactly the problem, what are the different scenarios that are
affected by the IPv4 address space depletion and what are the
possible approaches to address the problem. In addition, we
need to identify the different relevant aspects of the problem
and solution space that need to be taken into account during
the discussion of the solution space.
- Motivation for SHARA: Discuss the benefits and potential
issues with a Port-Extended IPv4 addressing approach.
- Port-Extended IPv4 addressing approaches: Explore the solution
space for Port-Extended IPv4 addressing and the implications of
the relevant aspects previously identified.
- Interaction with other efforts. There are a significant
number of efforts in related areas, such as the work being
done in the BEHAVE WG and the SOFTWIRES WG. It is then relevant
to understand how the proposed mechanisms interact with these.
- Implication for the deployment of IPv6. Any mechanism that
aims to extend the lifetime of IPv4 can potentially delay IPv6
deployment. An analysis of the impact of the adoption of these
techniques is needed.

This is non-wg forming BOF and the goal is to provide input
material to the community in general and the IESG in particular
for them to scope out what gaps still need to be addressed in
chartered WG items in other WGs.