No, this is not the failed experimental protocol IPv5 - this is something new.

IPv5 is a version of IP that is designed to replace both IPv4 and IPv6 (if version 6 ever becomes widely deployed in the real world). IPv5 allows for a limited but flexible set of options that make the packet simple yet powerful. IPv5's biggest features are that it automatically sets up networks and new nodes in a network and that it can allow a network (or portion of a network) to operate at near 100% efficiency during periods of congestion.

As for addresses, this protocol has 120-bit addresses. However, the address field in the packet can have 3 different sizes, to make for 30-bit, 60-bit, and 120-bit address fields (with the other bits that add up to 120-bits implied by its current network). The idea is that in most cases, two communicating computers reside in the same general network - thus the smallest address-size can be used. The 128-bit address that IPv6 has is overkill and would require many unnecessary bits be transferred constantly through the internet. It is important that a packet header is as small as possible, because that header will be sent with every packet on the internet, and every router has to support it. Mo' bits mo' problems. IPv5 can support almost as many addresses as IPv6, but it has the ability to send these 120-bit addresses in only 30 bits of data, by implying that the other 90 bits are the same as its current network (and thus the destination and every router it passes through in the network).

IPv5 is designed so that routers can and must set themselves up and maintain a network automatically. This greatly eases the workload of network administrators, and allows networks to be much more easily created and maintained. Rather than require extensive set up, IPv5 allows routers to have a few options that allows administrators to control the network through router permissions. This system allows seamless integration of networks using other protocols inside an IPv5 network - another network will look like one single system using many IP addresses like any other. This can allow special applications like ad-hoc wireless networks to use different network protocol that optimizes for, say, power rather than speed.

The protocol is built so that very few bits are needed for the header. This can be important in wireless protocols where every bit requires not only bandwidth but also power, which is a scarce resource in wireless applications. The protocol is also built so that routers need perform operations very quickly. Sometimes efficient operation requires that the lines between internet abstraction layers are blurred, and this document encourages such blurring for the sake of efficiency. Sacrificing efficiency on a global scale for conceptual simplicity and interoperability between layers is neither appropriate nor realistic.

The considerations that went into making IPv5 are: minimum delay, maximum throughput, packet ordering, congestion control, corruption correction, security, least-cost routing, routing information propagation, automatic configuration and administrative autonomy. Also considered were special needs like that of real-time applications and broadcast media. While many of these considerations are at odds, balancing them is what a protocol is about.

2007 Nov 30
Billy Tetrud