Network Security Bible by Eric Cole & Ronald Krutz & James W. Conley

Author:Eric Cole & Ronald Krutz & James W. Conley
Language: eng
Format: epub
Published: 2011-02-16T05:00:00+00:00

Figure 15.3 IPv6 simplified header

Although the address fields are four times as long, the IPv6 header is only twice the size of the IPv4 header because the optimized IPv6 header eliminated IPv4 fields that are considered redundant or not useful. One such removed field that will tremendously increase the processing time of IPv6 as compared to IPv4 is the header checksum field. In today's routers the checksum needs to be recalculated for every packet traversing through the router because the TTL decrements. This alone will make IPv6 significantly faster than IPv4.

IPv7 and IPv8 Solutions

Shortly after the IPv6 was drafted, the IPv7 draft began circulating and was being touted as solving the IP shortage problem (although not many researchers took it seriously) by efficiently using the 32-bit addressing in the existing IPv4 addresses, keeping all other IPv4 protocol definitions intact. The plan is to redefine the IP classes altogether. The proposed definition is as follows:

Class A-1—1-126 (126 networks and 2543 hosts)

Class A-2—1-126 (1262 networks and 2542 hosts)

Class A-3—1-126 (1263 networks and 254 hosts)

Class B-1—128-191 (64 networks and 2543 hosts)

Class B-2—128-191 (642 networks and 2542 hosts)

Class B-3—128-191 (643 networks and 254 hosts)

Class C-1—192-223 (32 networks and 2543 hosts)

Class C-2—192-223 (322 networks and 2542 hosts)

Class C-3—192-223 (323 networks and 254 hosts)

Class D-1—224-239 (16 networks and 2543 hosts)

Class D-2—224-239 (162 networks and 2542 hosts)

Class D-3—224-239 (163 networks and 254 hosts)

Class E-1—240-254 (15 networks and 2543 hosts)

Class E-2—240-254 (152 networks and 2542 hosts)

Class E-3—240-254 (153 networks and 254 hosts)

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