Chapter 16: Dynamic Routing Protocols
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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Simplified Routing Tables
Route summarization simplifies routing tables by replacing more-specific addresses with an address that represents all the
specific addresses. For example, you can replace 2010:11:22:0:1000::1 and 2010:11:22:0:2000:679:1 with one summary
address, 2010:11:22::/32.
Guidelines
Typically, you would summarize at the boundaries of Area Border Routers (ABRs). Although, it is acceptable to configure
summarization between any two areas, it is better to summarize in the direction of the backbone so that the backbone
receives all the aggregate addresses and injects them, already summarized, into other areas.
Inter-Area Route Summarization
Inter-area route summarization summarizes routes on ABRs between areas in the autonomous system. To take advantage
of summarization, network numbers should be assigned in areas in a contiguous way to be able to lump these addresses
into one range.
External Route Summarization
External route summarization is specific to external routes that are injected into OSPFv3 using route redistribution. Ensure
that external ranges that are being summarized are contiguous.
Note: Summarizing overlapping ranges from two different routers could cause packets to be sent to the wrong destination.
Safeguard
When a summary address is configured, the C4/c CMTS automatically configures a discard route for the summary address
to prevent routing black holes and route loops.
Configuring OSPFv3 for IPv6
OSPFv3 for IPv6 is enabled by specifying an OSPFv3 router ID and an area at the interface configuration level. The
configuration process includes:
