(no subject)

This paper presents and analyzes IPNL, a NAT-extended Internet
protocol architecture designed to scalable solve the address
depletion problem of IPv4. A NAT-extended architecture is one where
only hosts and NAT boxes are modified. IPNL attempts to maintain all
of the original characteristics of IPv4, most notably address prefix
location independence. IPNL provides true site isolation, and allows
sites to be multi-homed without polluting the default-free routing
zone with per-site prefixes.

Given the popularity of NAT, its success at mitigating the address
depletion and scaling problems of IPv4. The authors have chosen to
define Internet architecture as one that preserves the original
characteristics of IPv4 while solving its scalability and address
depletion problems. All hosts have long-lived, globally routable
addresses that serve to also identify the host; routers are
stateless; a network's address prefix is assigned independently of
where the network attaches to the Internet; packets cannot be easily
hijacked by rogue or misconfigured hosts that are not on the physical
path of the packets.

According to the goals of NAT-extension, IPNL has following major
attributes:
- It's a NAT-extended architecture, which means that it maximizes
reuse of the existing IPv4 infrastructure, primarily by adding a new
layer above IPv4 that is routed by NAT boxes.
- It utilizes Fully Qualified Domain Names (FQDNs) as an end-to-end
host identifier in packets.
- It extends the IP address space such that the globally unique IP
address space forms the high order part of the IPNL address, and the
private IP address space forms its low order part.
- It completely isolates site addressing from global addressing.

The IPNL topology is the same as today's Internet topology: privately-
addressed realms connected to the globally-addressed Internet, and,
sometimes, to each other, by NAT boxes. IPNL has extend IP address,
from global IP to "global IP - realm - local IP". The new protocol
layer is added accordingly, adding IPNL layer between TCP/UDP and
Link. INPL header can cary two kinds of routable addresses. One is
FQDN of the host, and the other is IPNL address of the host. For
robustness, IPNL uses two basic mechanisms to overcome inability: an
"in-band trace" mechanism, and additional "path discovery" mechanisms
in hosts.

This paper is well written. The authors provided much detail for this
novel scheme for NAT-extended Internet protocol architecture. It's
obviously a research work with much originality. The main
contribution is to design and implement a new Internet architecture.
The point is to enhance the current NAT scheme before IPv6 and prove
that it is better or easier to deploy than IPv6. IPNL has a number of
interesting and even promising characteristics, such as the various
mechanisms for site isolation and scalable multihoming. However, a
few years passed, the architecture has not been deployed. Although
there are tons of problems with IPv6, it seems that IPNL is also hard
to deploy in the real world. In this paper's time, P2P applications
had not dominated the main traffic in the Internet. so the P2P issue
in NAT did not emerged. I think if deploying IPNl, we should consider
P2P problems, such as P2P file-sharing systems, P2P streaming, video
conference, and etc.
Received on Thu Nov 30 2006 - 10:59:02 EST