IS-IS is configured to support both IPv4 and IPv6 routing. Which statement is true?
A.
Separate IPv4 and IPv6 hellos will be sent.
B.
IPv6 will have a separate link-state database.
C.
IS-IS v6 support must be enabled under protocols isis.
D.
IS-IS sends IPv6 topology information as new TLVs in existing LSPs.
Explanation:
why not both C and D?
To enable an IPv6 unicast topology for IS-IS, include the ipv6-unicast statement:
isis {
topologies {
ipv6-unicast;
}
}
+
=================
https://tools.ietf.org/html/rfc5308
The LSP contains
typed variable-length data, often referred to as TLVs (type-length-
values). We extend the protocol with two new TLVs to carry
information required to perform IPv6 routing.
For IS-IS to carry IPv6 routes, you only need to add IPv6 addresses to IS-IS enabled interfaces or include other IPv6 routes in your IS-IS export policy.