Post IPv4

1
Post IPv4 completion Why are people
looking again at IPv6?

• Alain Durand

2
The Internet must supportcontinued,
un-interrupted growth regardless of IPv4
addressavailability

• DISCLAIMERComcast has not made any decisions
  to deploy any of the following technologies.

3
Post IPv4 completion

• The Internet edges will still be mostly IPv4
• Many hosts in the home (Win 9.x, XP,) are
  IPv4-only.
• They will not function in an IPv6 only
  environment.
• Few of those hosts will upgrade to Windows
  Vista.
• Content servers (web, Mail,) hosted on the
  Internet by many different parties will take time
  to upgrade to support IPv6.

4
Provisioning color code
IPv4-only dual stack provisioned dual stack, IPv6-only provisioned IPv6-only(no IPv4 stack)
device
link
router
network
5
Residentialdeployments
Double NAT v4v4
vs
Dual-stack lite(for home gateway)
6
Complexity Trade-off

• Double NAT v4v4 increase network complexity
• May require multiple realms of Net 10
• Loose end-to-end debugging
• Fragile realm boundaries
• May require source-based routing on access
  router
• Dual stack lite demand IPv6
• Require v6 home gateway
• Require deploying IPv6 network in the ISP

7
Wirelessdeployments
8
Complexity Trade-off

• NAT IPv6-gt IPv4
• Require DNS AAAA synthesis
• DNSsec impact
• How to differentiate an IPv4-translated
  addressfrom an IPv6 one?
• Require v6/v4 ALGs
• Dual stack lite
• No DNS requirements
• Require v4/v4 ALGs
• Require tunnel discovery to scale (DHCPv6 option)

9
Requirements non-requirements

• IPv6 -gt IPv4
• Outside of sensor networks, there does not seem
  to be many pure IPv6-only devices with no IPv4
  stack.
• Enabling communication between pure IPv6-only
  device (no IPv4 stack) and IPv4 servers may be
  unnecessary.
• Enabling communication between dual-stack device
  only configured with IPv6 and IPv4 servers is
  required.

10
Requirements non-requirements

• IPv4 -gt IPv6
• There will be IPv4 addresses available in small
  numbers for servers long after they are not
  available any more in large number for end
  devices.
• Deploying IPv6 services is more difficult than
  deploying IPv6 networks.
• Enabling communication between any IPv4 device
  and an IPv6-only server may not be an immediate
  priority.