Provisioning Phase: Link-local address assignment
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The cable modem constructs an
IPv6 link-local address from the EUI-64 (64-bit Extended Unique Identifier),
which is derived from the MAC address of the interface.
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NS (DAD)
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The cable modem uses an NS
(Neighbor Solicitation) message to perform duplicate address detection (DAD).
DAD verifies if the constructed link-local address is already in use. If there
is no response to the NS, the cable modem determines that the link-local
address is not in use. If a response is returned, it implies that the
link-local address conflicts with the MAC address, and the cable modem stops
the provisioning process.
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Provisioning Phase: Router Discovery
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The cable modem uses router
discovery to find a default router and identify prefixes on a HFC link.
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RS
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The cable modem sends an RS
(Router Solicitation) to the CMTS to trigger transmission of the periodic
Router Advertisement message (RA).
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RA
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The CMTS router sends
periodic RAs, each of which contains the:
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Provisioning Phase: DHCPv6
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Solicit
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The cable modem sends a
Solicit message to locate DHCP servers.
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init6(s) state
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No IPv6 addresses available
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Incorrect Prime Cable
Provisioning shared secret
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Incorrectly configured
Class of Service
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DOCSIS template parsing
errors (invalid option, include file - not found, and so on)
Network Registrar DHCP
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Incorrect DHCPv6
configuration
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DHCP server not there in
provisioning group
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No appropriate prefixes
defined (or do not match Prime Cable Provisioning RDU configuration)
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The cable modem sends a
Solicit message to locate DHCP servers.
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Prime Cable Provisioning
Network Registrar Extension
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Network Registrar extension
cannot contact DPEs
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Network Registrar extension
fails to find IPv6 DPEs in provisioning group
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Verify extensions are
connected to the RDU
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Network Registrar extension
gets DPE cache miss, sends request to RDU
RDU
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Incorrect IP address of RDU
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Incorrect RDU port
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RDU cannot be pinged from DPE
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Configuration generation
failing at RDU
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RDU licenses exceeded, not
configured
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Device detection failing at
RDU
DPE
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DPEs not assigned to
provisioning group
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DPEs cannot be pinged from
DHCP server
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DPE interfaces not enabled
for IPv6 provisioning
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Provisioning group not
enabled for IPv6 provisioning
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Relay-Forw
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The relay agent forwards the
complete DHCPv6 message received from the cable modem to the DHCPv6 server.
The relay agent adds relay
agent message fields and options, such as:
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Peer-address
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Link-address
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Interface ID
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Relay-Repl
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The relay agent extracts the
server response and forwards it to the cable modem, via the CMTS.
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Advertise
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The DHCP server, in response
to the Solicit message that it received from the cable modem, returns an
Advertise message to indicate that it is available for DHCP service.
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Request
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On receiving the Advertise
message, the cable modem sends a Request message to request configuration
parameters, including IP addresses, from a specific server.
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Relay-Forw
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The relay agent forwards
the message to the DHCPv6 server.
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Relay-Repl
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The relay agent extracts
the server response and forwards it to the cable modem, via the CMTS.
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Reply
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The CMTS forwards the REPLY
message received from the DHCP server, containing assigned addresses and
configuration parameters.
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init6(i) state
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Note
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DHCPv6 clients can be
provisioned in the Rapid Commit mode. Rapid commit features a two-message
exchange, instead of the usual four-message exchange. The two-message exchange
involves a Solicit and a Reply, while the four-message exchange involves the
Solicit–Advertise–Request–Reply. All these messages are wrapped in a Relay-Forw
or Relay-Repl message if they go through a relay agent.??If rapid commit is
enabled, the DHCP server responds to a Solicit (that is wrapped in a Relay-Forw
message) with a Reply (that is wrapped in a Relay-Repl message). If you disable
rapid commit, the DHCP server responds with an Advertise (that is wrapped in a
Relay-Reply) message.
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NS (DAD)
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Once the DHCPv6 message
exchange is complete, the cable modem confirms if the link-local address is not
already in use via DAD. If it does not receive a response, then it deems the IP
address acquisition to be successful.
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Provisioning Phase: ToD
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Request
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After obtaining an IPv6
address, the cable modem requests the time of day from the RFC 868 time server.
The IPv6 addresses for servers are supplied through DHCPv6 options.
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init6(t) state - No route
from time server (DPE) to modem
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Response
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Provisioning Phase: TFTP
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TFTP-Get
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The cable modem, using
TFTP, downloads the configuration file. The IPv6 addresses for servers and the
name of the configuration file are made available via DHCPv6.
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init6(o) state
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Routing issues between CMTS
and DPE
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No route from TFTP server
(DPE) to modem
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DPE cache miss (static
file, and RDU down or does not have file)
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File not found at TFTP
server (DPE)
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DPE cache miss (dynamic
file)
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DPE IP validation failure
(for example, the IP address of the device is not what was expected, the
Dynamic Shared Secret is enabled on CMTS, or a hacker is spoofing as a DOCSIS
modem)
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TFTP RSP (config file)
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Routing issues between DPE
and CMTS
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The cable modem is now
provisioned for IPv6 operations.
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