HP A7533A - Brocade 4Gb SAN Switch Base, Administrator'S Manual

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Fabric OS 6.2 administrator guide 37
IPv6 autoconfiguration
IPv6 can assign multiple IP addresses to each network interface. Each interface is configured with a link
local address in almost all cases, but this address is accessible only from other hosts on the same network.
To provide for wider accessibility, interfaces are typically configured with at least one additional global
scope IPv6 address. IPv6 autoconfiguration allows more IPv6 addresses, the number of which is dependent
on the number of routers serving the local network and the number of prefixes they advertise.
An upgrade from Fabric OS 6.1 or earlier, which does not support IPv6 autoconfiguration, to a platform
that does support IPv6 autoconfiguration, such as Fabric OS 6.2 or later, causes IPv6 autoconfiguration to
be enabled on the upgraded platform. In upgrades or downgrades between versions of Fabric OS that
support autoconfiguration, the enabled state of IPv6 autoconfiguration is not changed.
There are two methods of autoconfiguration for IPv6 addresses, stateless and stateful.
Stateless allows an
IPv6 host to obtain a unique address using the IEEE 802 MAC address; stateful uses a DHCPv6 server
which keeps a record of the IP address and other configuration information for the host. Whether a host
engages in autoconfiguration and which method it uses is dictated by the routers serving the local network,
not by a configuration of the host. There can be multiple routers serving the network, each potentially
advertising multiple network prefixes. Thus the host is not in full control of the number of IPv6 addresses that
it configures, much less the values of those addresses, and the number and values of addresses can
change as routers are added to or removed from the network.
When IPv6 autoconfiguration is enabled, the platform engages in stateless IPv6 autoconfiguration. When
IPv6 autoconfiguration is disabled, the platform relinquishes usage of any autoconfigured IPv6 addresses
that it may have acquired while it was enabled. This same enable and disable state also enables or
disables the usage of a link local address for each managed entity, though a link local address continues
to be generated for each nonchassis-based platform and for each CP of a chassis-based platform because
those link local addresses are required for router discovery. The enabled or disabled state of
autoconfiguration is independent of whether any static IPv6 addresses have been configured.
Setting IPv6 autoconfiguration
1. Connect to the switch and log in using an account assigned to the admin role.
2. Take the appropriate following action based on whether you want to enable or disable IPv6
autoconfiguration:
• Enter the
ipAddrSet -ipv6 -auto
command to enable IPv6 autoconfiguration for all managed
entities on the target platform.
• Enter the
ipAddrSet -ipv6 -noauto
command to disable IPv6 autoconfiguration for all
managed entities on the target platform.
Date and time settings
Switches maintain the current date and time inside a battery-backed real-time clock (RTC) circuit receiving
the date and time from the fabric’s principal switch. Date and time are used for logging events. Switch
operation does not depend on the date and time; a switch with an incorrect date and time value still
functions properly. However, because the date and time are used for logging, error detection, and
troubleshooting, you should set them correctly.
In a Virtual Fabric there can be a maximum of eight Logical Switches per director or enterprise-class
platform. Only the default switch in the chassis updates the hardware clock. When the date command is
entered from a non-principal pre-Fabric OS 6.2.0 switch, it is dropped by a Fabric OS 6.2.0 switch and
the pre-Fabric OS 6.2.0 switch does not receive an error.
Authorization access to set or change the date and time for a switch is role-based. For an understanding of
role-based access, see ” Role-Based Access Control (RBAC) ” on page 67.
If you are running a Fabric OS version earlier than 6.0.0 and secure mode is not enabled, a change in
date or time to one switch is forwarded to the principal switch and distributed to the fabric. If the FCS
policy has been set, date or time changes can be made only on the primary FCS switch and distributed to
the fabric.
Setting the date and time
1. Connect to the switch and log in using an account assigned to the admin role.