Chapter 23: IPv6
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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Figure 92:
Scenario for Prefix Stability
The setup in the figure above shows two C4/c CMTSs connected to one northbound router (NBR). In this scenario the cable
modem is initially connected to the first one but then is moved to the second one as a result of node split.
The DHCPv6 server is configured to delegate the IPv6 prefixes to SYS-1 (System-1) and SYS-2 (System-2). There are three
different prefix ranges configured in this example. First, any residential subscriber on SYS-1 is always delegated one of the
/64 IPv6 prefixes from the pool FC0D:C422:FFFF::/48. Second, any residential subscriber on SYS-2 is always delegated one
of the /64 prefixes from the pool FC0D:C420:FFFF::/48.
A third prefix, 2009:0DB8:85A2:0631::/64, is a floating prefix and is delegated to a commercial customer, no matter which
of the two C4/c CMTSs this commercial customer may be connected to.
Note: For more information on how the C4/c CMTS uses IS-IS, Multiple Topology IS-IS, and OSPF (including OSPFv3), see
the appropriate sections of the see "
(page 457) chapter.
DHCPv6 Server
The procedure below provides an example of Prefix Stability configured to use IS-IS. It assumes a Level 1 type node.
Configure the DHCPv6 server to allocate a static IPv6 PD route to the gateway/CPE behind this modem. Static IPv6 PD
means if a modem/CPE is moved from SYS-1 to SYS-2 or vice versa, the DHCPv6 Server will lease the same IPv6 PD to this
gateway/CPE.
Configuring Prefix Stability Using IS-IS
There are two parts of this procedure. Part 1 is the configuration of the first C4/c CMTS.
To Configure IS-IS on SYS-1
1.
Configure IS-IS at the node level:
configure router isis is-type level-1
configure router isis net 47.0001.0002.0003.0004.00
configure router isis metric-style wide level-1-2
configure router isis address-family ipv6 multi-topology
configure router isis address-family ipv6 enable
configure router isis address-family ipv4 enable no