AIX Version 4.3 Differences Guide

of the routing applications are ported to AIX, specifically, ndpd-router and
updates to ndpd-host and ndp.
AIX 4.3.2 adds the following IPv6 functions:
• IPv6 unicast routing support
• IPv6 multicast routing support - no mrouted6 though
• IPv6 anycast address support - mostly receive processing
• IPv6 multi-homed link local and site local support. The reason for adding
multi-homed host support is because most routers are multi-homed and need
the ability to reference different hosts on different links at the link local and site
local levels.
7.6.2.1 IPv6 Unicast Routing
A packet sent to a unicast address is delivered to the interface identified by that
address.
There are two main aspects added in AIX 4.3.2: ndpd-router and the some netinet
changes.
The first major function is ndpd-router. The ndpd-router command provides a
protocol engine for NDP and RIPng. It provides a simple method to distribute
routes between gateways. This function is redundantly provided by gated. The
routing specific mechanisms, like router advertisements and answers to router
solicitations are handled by ndpd-router. RIPng is the follow-on for RIP with
regards to IPv6.
The other major function is to provide extensions to the icmpv6 support so that all
the NDP messages are supported. The new messages are for handling redirects.
The modifications to the IP input path allows the forwarding of IPv6 packets
between interfaces on the same machine. This function is identical to the IPv4
low-level routing function. The ip6forwarding function handles redirecting
incoming packets.
7.6.2.2 IPv6 Multicast Routing
The use of Internet Protocol (IP) multicasting enables a message to be
transmitted to a group of hosts, instead of having to address and send the
message to each group member individually. The Class D Internet addressing is
used for multicasting.
In general, there are two pieces to multicast routing. One piece is a method to
determine where the multicast message should be sent, and the other is a
method to dynamically change the place the packet goes based on network
conditions. In IPv4, the mrouted daemon handles both functions with the help of
IGMP. In IPv6, multicasting, and its related membership function, is all handled in
icmpv6. Usually, this is done by maintaining a table similar to a routing table that
is used to direct messages. In IPv4, this table is maintained in netinet and
updated by mrouted. In IPv6, INRIA adds it as an additional routing table. This way
the route command could be used to manipulate static multicast routes.
170 AIX Version 4.3 Differences Guide