Managing Serviceguard Nineteenth Edition, Reprinted June 2011

All Node Addresses = FF02:0:0:0:0:0:0:1 (link-local)
All Router Addresses = FF02:0:0:0:0:0:0:2 (link-local)
All Router Addresses = FF05:0:0:0:0:0:0:2 (site-local)
Network Configuration Restrictions
Serviceguard supports IPv6 for data and heartbeat IP.
To configure IPv6, the system should be set up in what is called a dual-stack configuration, which
requires the IPv6 product bundle.
The restrictions for supporting IPv6 in Serviceguard are listed below.
• Auto-configured IPv6 addresses are not supported in Serviceguard as HEARTBEAT_IP or
STATIONARY_IP addresses. IPv6 addresses that are part of a Serviceguard cluster
configuration must not be auto-configured through router advertisements, for example. They
must be manually configured in /etc/rc.config.d/netconf-ipv6.
• Link-local IP addresses are not supported, as package IPs, HEARTBEAT_IPs, or
STATIONARY_IPs. Depending on the requirements, the package IP could be of type site-local
or global.
• Serviceguard supports only one IPv6 address belonging to each scope type (site-local and
global) on each network interface (that is, restricted multi-netting). Therefore, up to a maximum
of two IPv6 STATIONARY_IPs or HEARTBEAT_IPs can be mentioned in the cluster
configuration file for a NETWORK_INTERFACE: one being the site-local IPv6 address, and the
other being the global IPv6 address.
NOTE: This restriction applies to cluster configuration, not package configuration: it does
not affect the number of IPv6 relocatable addresses of the same scope type (site-local or global)
that a package can use on an interface.
• Serviceguard supports IPv6 only on the Ethernet networks, including 10BT, 100BT, and Gigabit
Ethernet
NOTE: Even though link-local IP addresses are not supported in the Serviceguard cluster
configuration, the primary link-local address on the Serviceguard primary interface will be switched
over the standby during a local switch. This is because of two requirements: First, the dual stack
(IPv4/IPv6) kernel requires that the primary IP address associated with an interface must always
be a link-local address. Second, Serviceguard requires that the site-local and global IPs be switched
to the standby network interface.
IPv6 Relocatable Address and Duplicate Address Detection Feature
The IPv6 networking stack has a new feature, Duplicate Address Detection (DAD), that was not
previously available in IPv4. When an address is being added, the DAD detects a duplicate address
that is already being used on the network. It sends out a multicast message to the network
neighborhood, and requires at least one second to listen for responses from other nodes. If no
responses are received in that time, the relocatable IPv6 address is considered free to use. For
more information regarding this feature, please refer to the RFC 2462.
The effect of this feature on Serviceguard is that the time required to add each IPv6 relocatable
address will be at least one second longer than adding a corresponding IPv4 address. Depending
on the number of IPv6 addresses configured within a package, this could have a moderate to
significant impact on package start time.
If you do not need duplicate address detection, you can disable the DAD feature by setting the
kernel parameter ip6_nd_dad_solicity_count to 0. Please note that this kernel parameter
applies to the entire system. If you turn it off, you disable it for all applications on the system. For
systems where DAD is not required, disabling this feature can significantly improve the start time
of package packages containing a large number of IPv6 relocatable addresses.
To determine the current state of DAD on your system, use the ndd -get command to see the
current value of the kernel parameter.
Network Configuration Restrictions 367