Chapter 23: IPv6
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
733
This process of adding PD routes to the C4/c CMTS route table is referred to as Route Injection, which is needed to route
traffic destined to IPv6 clients behind CPE routers. The C4/c CMTS marks injected routes as having protocol type PD. Their
admin distance is configurable. The default distance is 2. Manually configured static routes have higher priority because
their admin distance is 1.
Route Injection can be enabled or disabled either per interface or globally, but the Prefix Delegation subfeature is always
enabled in the C4/c CMTS. The C4/c CMTS recognizes the Identity Association for Prefix Delegation (IA_PD) options present
in DHCPv6 messages in order to update the PD database. Routes from the PD database are used to update the C4/c CMTS
route table.
When the DHCPv6 server attempts to assign the same or overlapping prefixes to a different CPE, the C4/c CMTS checks its
routing table and uses the lease query mechanism to verify the server’s records of the two prefixes (clients) in question. If
the lease query response proves that the C4/c CMTS routing table is out of sync with the server, then the C4/c CMTS
updates its routing table accordingly. However, if the C4/c CMTS routing table is in sync with the server but the server is
mistakenly trying to assign the same or overlapping prefixes to a different client, then the C4/c CMTS logs a message (at
the warning level) without injecting the most recent route.
The C4/c CMTS supports up to a maximum of four prefixes per CPE router. Prefixes beyond that are not learned by the PD
database or injected into the route table.
If route injection is disabled globally, then all routes learned or injected by the PD feature are purged from the route table.
If route injection is enabled globally and on an interface, then the C4/c CMTS injects all prefixes learned on that interface.
CLI Commands for PDRI
The following table lists the CLI commands used to configure and show PDRI:
Table 94.
CLI Commands for Prefix Delegation and Route Injection
Purpose
CLI Command
Enable [disable] route injection globally. Default =
enabled.
configure ipv6 pd-route-injection [no]
Enable [disable] route injection on a given cable-mac
interface.
configure interface cable-mac <WORD> ipv6
pd-route-injection [no]