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The Way Business Is Moving

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Issue Date: August 2002

IPv6

August 2002
Peter Fehrsen: business unit manager - Enterprise, Westcon SA

Much has been discussed around IP Version 6 over the last few years, however, not much thought has gone into the implications of IPv6 becoming a reality and the requirements for companies interfacing with public networks and the World Wide Web.

Do companies have a roll out strategy to implement IPv6 on their networks? What are the potential costs involved? Do the vendors (manufactures of their networking equipment) have a solution and a strategy?
Peter Fehrsen: business unit manager - Enterprise, Westcon SA
Peter Fehrsen: business unit manager - Enterprise, Westcon SA
IPv6 - Where did it come from and why the need for it?
In the early nineties, the IETF became aware of a shortage of IPv4 addresses, and technical limitation imposed by IPv4 in deploying new protocols. An IPng (IP next generation) group was formed to start looking at ways of resolving these issues. The result of this group's efforts is IPv6.
What will IPv6 give us?
IPv4 uses only 2^32 bits for IP address space, giving us a maximum of four billion nodes to be identified on the Internet. Four billion sounds like a large number, however, that is less than the total human population, granted not every human will require an IP address but when looking at where technology is going, home appliances, telephones, TVs, DVD players etc, will all eventually have an IP address, IPv4 just will not be able to deliver. Yet, IPv6 allows 2^128 bits for IP address space, allowing three hundred forty decillion nodes to be uniquely identified on the Internet. Larger address space allows true end-to-end communication, without NAT or other short-term workaround solutions currently used to get around the IPv4 address shortage. NAT has been a limitation to new protocol deployment and needs to be decommissioned in order to allow growth.
Beneficial features of IPv6
* Autoconfiguration: With IPv4, DHCP has been there but is optional. A novice user can get into trouble if they visit an offsite without a DHCP server. With IPv6, 'stateless host autoconfiguration' mechanism is mandatory.
* Security: With IPv4, IPsec is optional and you need to ask the peer if it supports IPsec. With IPv6, IPsec support is mandatory. By mandating IPsec, we can assume that you can secure your IP communication whenever you talk to IPv6 devices.
* Friendly to traffic engineering technologies: IPv6 was designed to allow better support for traffic engineering like diffserv or intserv (RSVP). We do not have single standard for traffic engineering yet; so the IPv6 base specification reserves a 24-bit space in the header field for those technologies and is able to adapt to coming standards better than IPv4.
* Multicast: Multicast is mandatory in IPv6, which was optional in IPv4. The IPv6 base specifications themselves extensively use multicast.
* Better support for ad-hoc networking: Scoped addresses allow better support for ad-hoc (or 'zeroconf') networking. IPv6 supports anycast addresses, which can also contribute to service discoveries.
* A cure to routing table growth: The IPv4 backbone routing table size has been a big headache to ISPs and backbone operators. The IPv6 addressing specification restricts the number of backbone routing entries by advocating route aggregation. With the current IPv6 addressing specification, we will see only 8192 routes on the default-free zone.
* Simplified header structures: IPv6 has simpler packet header structures than IPv4. It will allow future vendors to implement hardware acceleration for IPv6 routers easier.
* Allows flexible protocol extensions: IPv6 allows more flexible protocol extensions than IPv4 does, by introducing a protocol header chain. Even though IPv6 allows flexible protocol extensions, IPv6 does not impose overhead to intermediate routers. It is achieved by splitting headers into two flavours: the headers intermediate routers need to examine, and the headers the end nodes will examine. This also eases hardware acceleration for IPv6 routers.
* Smooth transition from IPv4: There were a number of transition considerations made during the IPv6 discussions. Also, there are a large number of transition mechanisms available.
* Follows the key design principles of IPv4: IPv4 was a very successful design, as proven by the ultra large-scale global deployment. IPv6 is 'new version of IP', and it follows many of the design features that made IPv4 very successful. This will also allow smooth transition from IPv4 to IPv6.


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