2031:0000:130f:0000:0000:09c0:876a:130b

A few shortcuts to this addressing are:

• Leading zeros in a field are optional, so that 09c0 can be written 9c0, and 0000 as 0.

• Successive fields of zeros (any number of them) are represented as ::, but only once in an address (because if used more than once, the address parser has no way of identifying the size of each block of zeros). So, the previous address can be written:

  
  2031:0:130f::09c0:876a:130b
  

The use of the double-colon abbreviation makes many addresses small, for example ff01:0:0:0:0:0:1 becomes ff01::1.

Link-local addresses have a scope limited to the link, and use the prefix fe80::/10. Loopback addresses have the address ::1. Multicast addresses are identified by the prefix ff00::/8 (there are no broadcast addresses in IPv6).

The IPv4-compatible addresses in IPv6 are the IPv4 decimal quad addresses prefixed by ::. For example, an IPv4 address that would be interpreted as ::c0a8:1e01 can be written as ::192.168.30.1.

Prime Cable Provisioning supports provisioning of CableLabs devices in dual stack mode. By default, dual stack mode is disabled and in such a case, the DPE cache stores these configurations using either MAC address (for IPv4 mode CM) or DUID address (for IPv6 mode CM). When a CM transitions from one IP mode to another IP mode, the previous IP mode configuration is deleted from the DPE cache and replaced with the new IP mode configuration generated from the RDU. So if the CM transitions from IPv4 to IPv6 mode, the IPv4 configuration cache is removed from the DPE, and is replaced with the IPv6 configuration details.

When dual stack is enabled, DPE caches both IPv4 and IPv6 configuration details. The IPv4 configuration is stored using the MAC address and the IPv6 is stored using its DUID and none of the configuration details are deleted. You can view both the configuration details using the show device-config command.

You can enable or disable dual stack provisioning either from the Admin UI or using the API without restarting the RDU. Dual stack provisioning can be specified at any acceptable point in the property hierarchy. You can use the Device, Provisioning Group, Class of Service, DHCP Criteria, and Technology Defaults properties to accomplish this. To enable dual stack from the Admin UI at CoS, DHCP Criteria, and Device level, set the property /dualStack/provisioning/mode/enable to true. The API constant is PolicyKeys.DUAL_STACK_PROVISIONING_MODE_ENABLE.

Dual Stack Device Disruption Behavior

Note	Prime Cable provisioning can disrupt only CableLabs DOCSIS, PacketCable and eRouter devices.

In single stack mode, when device disruption is initiated, Prime Cable Provisioning uses either IPv4 or IPv6 address to disrupt the device, based on the discovered data that is stored on the device (i.e., DHCPv4 or DHCPv6).

Once dual stack mode is enabled, the device disruption behavior depends on the value set for the property dualStack/disruption/pref/mode. This property can take the following values:

• Dual-stack—This is the default value set for this property. In this case, Prime Cable Provisioning sends two device disruption requests, one each for IPv4 and IPv6 address to disrupt the device.
• IPv4—In this case, IPv4 address is used to disrupt the device and the devices that have only IPv6 address are ignored.
• IPv6—In this case, IPv6 address is used to disrupt the device and the devices that have only IPv4 address are ignored.

The API constant for this property is PolicyKeys.DUAL_STACK_DISRUPTION_PREF_MODE. You can specify this property at any acceptable point in the property hierarchy.

RFC 4213 defines dual stack as a technique to provide complete support for both Internet protocols—IPv4 and IPv6—in hosts and routers. Any network stack that supports both IPv4 and IPv6 is called a dual stack, and a host implementing a dual stack is called a dual-stack host.

Prime Cable Provisioning provisions cable modems in the following IP modes:

• IPv4 only—In this mode, the cable modem requests a DHCPv4 server for an IPv4 address and related operational parameters.

• IPv6 only—In this mode, the cable modem requests a DHCPv6 server for an IPv6 address and related operational parameters. The modem uses the IPv6 address to obtain the current time-of-day and a configuration file.

• Dual stack—In this mode, the cable modem acquires both IPv6 and IPv4 addresses and parameters through DHCPv6 and DHCPv4 almost simultaneously, prioritizing the use of the IPv6 address to acquire time-of-day and a configuration file.

While provisioning in the IPv4 and IPv6 modes, the cable modem operates with only one IP address type (v4 or v6) at any given time. For this reason, the IPv4 and IPv6 modes of provisioning are called single stack modes. In single stack mode, Prime Cable Provisioning saves discovered data only for the most recent IP mode that a cable modem is provisioned in. So, if a dual stack device boots in IPv4 mode, then in IPv6 mode, only IPv6 data is discovered and stored.

In the dual stack mode, you can manage the cable modem via IPv4 and IPv6 addresses simultaneously. In this mode, the modem acquires a second IP address after it is operational. Using this feature, you can provide streamlined migration from IPv4 to IPv6 in DOCSIS networks.

The DOCSIS 3.0 standard defines several new options for DHCPv4 and DHCPv6. DHCPv6 options do not use any DHCPv4 options; they are unique and separate. For the list of DHCPv6 options that 
 Prime Cable Provisioning also supports, see the Cisco Prime Network Registrar End-User Guides.

Configuring Prime Cable Provisioning to support IPv6 involves two distinct workflows:

• Configuring the DPEs in the provisioning group.

• Configuring the Cisco Prime Network Registrar servers in your network.