1. Internet Protocol Version 6 Specifications
Chris Theodoridis
Craig Young

2. Background – IPv4 Problems
Internet Assigned Numbers Authority Concerned About Internet Growth
IPv4 Provides 32-bits for Addressing
Approximately 4 billion host addresses
No Quality of Service Provisions in IPv4
IPv4 Provides No Means For Authentication or Integrity Checking
Craig

3. Current Remedies for IPv4
Address Limitations:
NAT – Network Address Translation
CIDR – Classless InterDomain Routing
Authentication/Message Integrity
Handled by Upper-Layer Protocols
QoS
IPv4 is Designed to be Best-Effort
Chris

4. IPv6 Enhancements 128-bit Addresses Streamlined 40 byte Header
Enough for Every Grain of Sand to Have an IP address!
Streamlined 40 byte Header
Intended to Compensate JUMBO addresses
Options have been Removed From Main Header
“Flow” Labeling
In the future, “Flows” could address issues related to packet scheduling and QoS
Internet Layer Support for Authentication/Data Integrity & Privacy
Craig

5. IPv6 Header Format
IPv6 packet may carry 0, 1, or more extension headers
These headers only examined by node identified by destination address field
One exception is Hop-by-Hop Options Header
Specified by value 0 in Next Header field of IPv6 header
Must be examined in order presented
Chris

6. Extensible Headers Hop-By-Hop Options Routing (Type 0) Fragment
Destination Options
Authentication
Encapsulating Security Payload
Chris

7. What is a ‘Flow’? RFC 2460 Loosely Defines “Flow”
Packets In a Traffic Flow are Grouped
“Flow” Concept Anticipates Future Needs of the Internet Protocol
Handling For:
Real-Time Service
Non-Default QoS
Craig

8. Upper-Layer Consideration
Checksum Issues
Maximum Packet Lifetime
Maximum Upper-Layer Payload Size
Responding to IPv6 Packets
Craig

9. Upper-Layer Checksum Issues
Increased Address Size
TCP Uses Info from IP Layer in Checksum
IPv6 Node Must Compute Checksum
Under IPv4 UDP Doesn’t Have Checksum
Craig

10. Maximum Packet Lifetime
IPv4 Used Time-To-Live (TTL)
IPv6 Renames TTL “Hop Limit”
Max Lifetime Mechanism Must Exist in Upper-Layer
How might this Impact End to End Communication?
Craig

11. Maximum Upper-Layer Payload
Increased Header Size
TCP MSS Will Be Smaller
TCP Over IPv4:
MSS = Max Packet Size – 20 B Min Header
TCP Over IPv6
MSS = Max Packet Size – 40 B Fixed Header
Craig

12. Reverse Routing How to Create a Reverse Route?
Routing Header Information must be Verified
Use Local Configuration
Use of Route Header Reversal Limited When Sender is Verified
Craig

13. Transition from IPv4 to IPv6
IPv6-capable systems can be made backward-compatible to facilitate transition
Does not address IPv4-capable systems handling IPv6 datagrams.
Two proposed solutions:
Dual-Stack Approach
Tunnel Approach
Chris

14. Dual-Stack Approach
Chris
(slide #33)

15. Tunneling Approach
Chris
(slide #34)

16. Related Work ICMPv6 – RFC 2463
IP Encapsulating Security Protocol (ESP) – RFC 2406
Craig

17. Critique Is a 128-bit address overkill?
340 Undecillion Addresses!!!!
Should NAT (or similar) be used more?
Will Traffic Classes be implemented better than TOS was?
The Internet was designed to be updated at the Application Layer
Chris

18. Questions ?