Gearing up for IPv6
has its limitations, so IPv6 is the future, says Shrikant Shitole, Business
Development Manager, Cisco Systems India & Saarc.
Picture this. You are not able to log on to the Internet because your computer
says, Sorry, all IP addresses are now being used! What does one
do in circumstances like these? Right now nothing. With the rapid growth of
the Internet and the proliferation of wireless devices that require unique IP
addresses, IPv4 is beginning to show its age.
But the rumblings of the next-generation IP protocolversion 6are
growing louder. IPv6, or Internet Protocol version 6, is the next generation
protocol designed by the Internet Engineering Task Force (IETF) to replace the
current version of the Internet protocol, IP version 4 (IPv4), and
is now said to be the remedy for shortages of IP addresses.
The case for IPv6
The escalating demand for IP addresses is the catalyst for IPv6. Its estimated
that, in the wireless arena alone, more than a billion mobile phones, personal
digital assistants (PDAs), and other wireless devices will require Internet
access, and each will need its own unique IP address. Additionally, billions
of new, always-on Internet appliances for the homefrom the TV to the refrigerator
to the utility meterwill also be connected through various technologies.
Each of these devices will also require its own IP address. Clearly then, with
the exponentially increasing demand for IP addresses, the world is outgrowing
The need for more addresses is compounded by the fact that addresses have not
been distributed evenly worldwide. Although IPv4 theoretically can support as
many as four billion unique addresses, the actual allocation of space has locked
up nearly 75 percent of these addresses. In contrast to IPv4, which has 32 bits
of address space, IPv6 has 128 bits of address space, pushing the theoretical
limit of unique IPv6 nodes to roughly 3.4 x 1038 or about 340 billion billion
billion billion unique addresses.
A look around the world shows that IPv6 adoption is taking place. Japan was
the first country to put in place a national strategy for adoption of IPv6 in
2000. In the US, North America IPv6 Task Force was set up in December 2001,
and it has been promoting the adoption of this technology. Even China announced
a national strategy in 2004 for promotion and adoption of IPv6. In India, the
industry has just recently realised the need. TRAI issued its recommendations
on Transition from IPv4 to IPv6 in India in January 2006.
The catalyst in action
IPv6, as specified by the IETF, offers the following benefits to enterprises:
- Expanded IP addresses to accommodate the widespread proliferation
of Internet devices such as personal computers, personal digital assistants,
wireless devices and new Internet appliances.
- IPv6s auto configuration feature or auto-discovery
will eliminate todays labour-intensive and expensive approach of dynamic
host control protocol (DHCP) servers that most large organisations use to
manage their IPv4 addresses.
- IPv6 will use a stateless autoconfiguration
that combines an interface ID number, such as the machines existing
MAC address, and a network prefix from the local router, to assign its IP
address instead of one allocated by a DHCP server.
- IPv6 will also provide a peer-to-peer applications architecture
that will support a global, end-to-end addressing scheme. This set-up will
eliminate the need for network address translation devices at the edge of
large enterprise networks; these can slow down the encryption process and
are inefficient for applications such as voice over IP, mobile IP, and distributed
Apart from the obvious benefits to large enterprises, this represents a chance
for aggressive and forward-thinking ISPs to develop an IPv6 network to carry
gaming and eventually other types of digital content such as movies, television
programming and music. Other than the new revenue streams, IPv6 should also
bring about cost-reduction in larger networks. With the improvement in routing,
inherent security, and the auto-configuration capability, tomorrows networks
will cost less to deploy, maintain and operate. Once you add services that either
reduce expenses elsewhere, i.e. communications (VoIP, IP videoconferencing,
etc), or improve productivity (true mobile access to files, information, inventory,
etc), the cumulative ROI effect is positive for both adopters and developers.
The question isnt if but when the world will migrate
to IPv6. ISPs and enterprises will have to move hand-in-hand towards the adoption
because it involves expenditure for both. Each will need to nudge the other
forward in the adoption process.
Network designers recommend deploying IPv6 first at the edge and then moving
towards the network core to reduce the cost and operational impact of integration.
The key strategies used in deploying IPv6 at the edge of a network involve carrying
IPv6 traffic over an IPv4 network, and allowing isolated IPv6 domains to communicate
with each other before making a complete transition to a native IPv6 backbone.
It is also possible to run IPv4 and IPv6 throughout the network, from all edges
through the core, or to translate between IPv4 and IPv6 to allow hosts communicating
in one protocol to communicate transparently with hosts running the other.
All these techniques permit networks to be upgraded and IPv6 deployed incrementally,
with little to no disruption of IPv4 services. The four key strategies for deploying
- Deploying IPv6 over dual-stack backbones. This
technique allows IPv4 and IPv6 applications to co-exist in a dual IP layer
routing backbone. All routers or a portion of them (for example, access CPE
routers and aggregation routers are dual-stack, but core routers stay as they
are) in the network need to be upgraded to be dual-stack, with IPv4 communication
using the IPv4 protocol stack and IPv6 communication using the IPv6 stack.
- Deploying IPv6 over IPv4 tunnels. These tunnels
encapsulate IPv6 traffic within IPv4 packets, and are primarily for communication
between isolated IPv6 sites or connection to remote IPv6 networks over an
IPv4 backbone. The techniques include using manually-configured tunnels, generic
routing encapsulation tunnels, semi-automatic tunnel mechanisms such as tunnel
broker services, and fully-automatic tunnel mechanisms such as 6to4 for WANs
and intra-site automatic tunnel addressing protocol for the campus environment.
- Deploying IPv6 over dedicated data links. This
technique enables IPv6 domains to communicate by using the same Layer 2 infrastructure
used for IPv4, but with IPv6 using separate frame relay or ATM permanent virtual
circuits, separate optical links, or dense wave division multiplexing.
- Deploying IPv6 over MPLS backbones. This technique
allows isolated IPv6 domains to communicate with each other, but over an MPLS
IPv4 backbone without modifying the core infrastructure. Multiple techniques
are available at different points in the network, but each requires little
change to the backbone infrastructure or reconfiguration of the core routers
because forwarding is based on labels rather than the IP header itself.
Five steps towards IPv6 adoption by enterprises
- Integrate IPv6 migration with normal product lifecycle
replacement. Enterprises can avoid spending money explicitly for IPv6
migration by folding it into planned product procurements from their existing
information technology budgets. If IT staffs include upgrades to IPv6 as part
of their regular procurement process and select IPv6-capable products from
now on, they can take an evolutionary approach to supporting the new protocol.
- Assess existing infrastructure hardware for upgradeability.
An enterprises top priority should be to take an inventory of its hardware
infrastructure that supports only IPv4. Software can be upgraded almost anytime,
but some hardware must be capable of supporting IPv6 by design. The devices
that are most likely to need attention are routers at the high and low end.
High-end routers tend to include acceleration hardware that might be limited
to 32-bit addresses. Low-end routers simply may have too little memory to
support IPv6 software.
- Use transition technologies judiciously. For routers
that must support the IPv6 service by an internal migration deadline but are
already slated for replacement shortly thereaftersay, within a few months
to one yearenterprises can incorporate tunneling into the network temporarily
until the end of the devices lifecycle. Tunneling involves routing IPv6
packets via virtual paths in the backbone by wrapping them in IPv4 network
address headers. Before delivery to end-points, the IPv6 packets are unwrapped
and delivered via IPv6 service.
- Integrate IPv6 training into the IT budget and process
now. Training might represent a fairly high cost of IPv6 migration, so
integrate it into the IT training budget and process as soon as possible.
To minimise confusion, IPv6 should be considered a different protocol from
IPv4and one that will take time to learn.
- Add IPv6 to all RFPs. Folding IPv6 support into
fresh procurement beyond the core network will help ensure that enterprises
meet internal adoption deadlines. This means including IPv6 support in all
IT requests for proposals. Doing so avoids the impasse of vendors not making
devices IPv6-enabled because RFPs dont specify it, and of enterprises
not upgrading because IPv6 is not available in certain products. The IPv6
deployment process is fairly straightforward. However, employees will need
training; routers and operating systems will need updates; management tools
will require enhancements; and enterprises will have to deploy IPv6-enabled
versions of applications. Integrating IPv6 procurement planning and training
into existing IT processes now will help enterprises meet their upgrade deadlines
and avoid unexpected and unnecessary costs.