Lindsay Goddard
Network Fundamentals
Chris Talaski
June 10, 2010 What are IPv4 and IPv6? IP stands for Internet protocol and the v stands for the version, in this case it would be version four or version six. The IPv4 is the currently used protocol and IPv6 seems to be the next protocol to be most widely deployed. A golden rule says to “never touch a running system.”(Morgan, 2007, page 2) At least not if they are functioning like they are supposed to. Since IPv4 is reaching its limits, then IPv6 may be the next viable option. IP addresses are uniquely identified at the Network Layer of the OSI Model. IPv4 was the first protocol to be most utilized and is nearly twenty years old. It uses a thirty-two bit source and destination addressing and can create up to 4, 294, 967, 296 unique addresses. IPv4 has four types of classes A, B, C, and D. It also uses a subnet mask in order to make up more unique addresses for the large number of computer used today. The shortage of available IPv4 addresses is growing. Subnet Masks help to reduce the number of unique IP addresses given to companies and corporations. These organizations are using Network Address Translation (NAT) firewalls to map many private addresses to single public addresses due to these limitations. NAT does not support standards- based network-layer security as well as creating complicated barriers to VoIP. (Miyamoto, 2008) There are many features of IPv4 addressing. IPSec is optional and should be supported externally. Both routers and the sending host fragment packets. The header includes options and a checksum. Address Resolution Protocol (ARP) uses broadcast ARP request frames to resolve IP to MAC/Hardware or link-layer address. The Internet Group Management Protocol (IGMP) manages membership in local subnet groups. ICMP Router Discovery is used to determine the IPv4 address of the best default gateway and is optional. Broadcast addresses are used to send traffic to all nodes on a subnet. They can be configured manually or through DHCP. Also most support a 576-byte packet size, even possibly fragmented. IPv6, Internet Protocol version six, is the next advancement of IP’s. The Internet Engineering task force has named IPv6 as the next step from IPv4 stating that,
“It significantly increases the size of the address space used to identify communication endpoints in the internet thereby allowing it to continue its tremendous growth.”
IPv6 uses 128 bit source and destination addressing. This new protocol, to be released by 2025, will be able to crate three hundred and forty undecillion addresses. This would create more IP addresses than there are stars in the universe. (Miyamoto, 2008) IPv6 uses multicast or the ability to send one packet to multiple destinations. IPv6 also has a higher level of built-in security designed with mobile devices in mind. In IPv4 security was an issue. Mobile IPv6 unlike mobile IPv4 avoids triangular routing. IPv6 addressing has many new features. It has a new header format that minimizes header overhead. (see Figure 1 for example of an IPv6 header) By moving both the non-essential fields and extending headers with optional fields after the IPv6 header itself is how it is achieved. The IPv6 header can be made more efficient by processing intermediate routes. Unlike the IPv4 header which can only support forty bytes of options, the IPv6 header is constrained only by the size of the packet. (Miyamoto, 2008)
Figure 1: IPv6 Header
IPv6 header