Configuration Procedure; Enabling Ip Conflict Notification - HP FlexNetwork MSR2003 Configuration Manual

•
Update MAC entries of devices in the VLANs having ambiguous Dot1q or QinQ termination
configured.
In VRRP configuration, if ambiguous Dot1q or QinQ termination is configured for multiple
VLANs and VRRP groups, interfaces configured with VLAN termination must be disabled from
transmitting broadcast/multicast packets. Also, a VRRP control VLAN must be configured so
that VRRP advertisements can be transmitted within the control VLAN only. In such cases, you
can enable periodic sending of gratuitous ARP packets containing the following addresses:
The VRRP virtual IP address.
The primary IP address or a manually configured secondary IP address of the sending
interface on the subinterfaces.
When a VRRP failover occurs, devices in the VLANs can use the gratuitous ARP packets to update
their corresponding MAC entries in a timely manner. For more information about ambiguous Dot1q
or QinQ termination, see Layer 2—LAN Switching Configuration Guide.

Configuration procedure

The following conditions apply to the gratuitous ARP configuration:
•
You can enable periodic sending of gratuitous ARP packets on a maximum of 1024 interfaces.
•
Periodic sending of gratuitous ARP packets takes effect only when the link of the enabled
interface goes up and an IP address has been assigned to the interface.
•
If you change the interval for sending gratuitous ARP packets, the configuration is effective at
the next sending interval.
•
The frequency of sending gratuitous ARP packets might be much lower than the sending
interval set by the user in any of the following circumstances:
This function is enabled on multiple interfaces.
Each interface is configured with multiple secondary IP addresses.
A small sending interval is configured when the previous two conditions exist.
To configure gratuitous ARP:
Step
1. Enter system view.
2. Enable learning of gratuitous
ARP packets.
3. Enable the device to send
gratuitous ARP packets upon
receiving ARP requests
whose sender IP address
belongs to a different subnet.
4. Enter interface view.
5. Enable periodic sending of
gratuitous ARP packets and
set the sending interval.

Enabling IP conflict notification

By default, if the sender IP address of an ARP packet is being used by the receiving device, the
receiving device sends a gratuitous ARP request. It also displays an error message after it receives
an ARP reply about the conflict.
Command
system-view
gratuitous-arp-learning enable
gratuitous-arp-sending enable
interface interface-type
interface-number
arp send-gratuitous-arp
[ interval milliseconds ]
10
Remarks
N/A
By default, learning of gratuitous
ARP packets is enabled.
By default, a device does not send
gratuitous ARP packets upon
receiving ARP requests whose
sender IP address belongs to a
different subnet.
N/A
By default, periodic sending of
gratuitous ARP packets is
disabled.