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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Comparison of OSPFv3 and OSPFv2
Much of the OSPFv3 protocol is the same as in OSPFv2. The key differences between the OSPFv3 and OSPFv2 protocols are
as follows:
OSPFv3 only provides support for IPv6 routing prefixes and will handle the larger size IPv6 addresses. OSPFv2 only
supports IPv4 routing.
LSAs in OSPFv3 are expressed as prefix and prefix length. OSPFv2 uses address and mask.
The router ID and area ID are 32-bit numbers, which is the same as in OSPFv2, with no relationship to IPv6 addresses.
OSPFv3 uses link-local IPv6 addresses for neighbor discovery and other features.
OSPFv3 uses IPSec for authentication and OSPFv2 uses MD5.
OSPFv3 redefines LSA types.
The C4/c CMTS supports running both OSPFv2 and OSPFv3 at the same time, including running the protocols on the same
interface. It will also support passive interfaces on the:
Cable side.
Network side.
Loopback interfaces.
OSPFv3 on the C4/c CMTS supports point-to-point links, but does not support point to multipoint links.
Discovering Neighboring Routers
An OSPFv3 router sends a special message, called a Hello packet, out each OSPF-enabled interface to discover other
OSPFv3 neighbor routers. Once a neighbor is discovered, the two routers compare information in the Hello packet to
determine if the routers have compatible configurations.
Establishing Adjacency
The neighboring routers attempt to establish adjacency, which means that the routers synchronize their Link-State
Databases (LSDBs) to ensure that they have identical OSPFv3 routing information.
Link-State Advertisements
Adjacent routers share Link-State Advertisements (LSAs) that include information about: