Allied Telesis AT-x510-28GTX Command Reference Manual page 691

IP A P
DDRESSING AND ROTOCOL
- -
ARP MAC DISPARITY
For example, to flood only port1.0.1 to port1.0.3, use the commands:
awplus#
awplus(config)#
awplus(config-if)#
port1.0.1-port1.0.3
Usage, multicast Multicast-IGMP mode is enabled by using the command arp-mac-disparity
igmp mode multicast-igmp.
In this mode, the only difference to standard multicast mode is that the reception
of IGMP reports now controls the ports to which the L3 switch floods traffic. That
is, rather than simply flooding each packet destined for the NLB cluster IP address
to all ports on the egress VLAN, those packets are only sent to the switchports in
the VLAN that have received IGMP reports for the multicast group corresponding
to the NLB cluster MAC address.
Like arp-mac-disparity multicast, the command arp-mac-disparity
multicast-igmp puts the switch into a mode where it will accept disparate ARP
responses. Similarly, upon receiving a disparate ARP response, an ARP entry is
created for the IP/MAC in the content of the ARP packet. The difference with the
arp-mac-disparity multicast-igmp command is that the egress port is set to the
subset of ports in the VLAN that have received IGMP reports for the NLB cluster
MAC address.
Note that the ARP entry is updated as ports join/leave the IGMP group. If no ports
have received IGMP reports for the NLB cluster MAC address then the ARP entry
will have no egress ports and will simply drop packets destined for the NLB cluster
IP address.
Again, no FDB entry is created in response to receiving the ARP packet. However,
since the NLB server is operating in multicast mode with the IGMP option set and
is sending IGMP reports, an FDB entry will already exist for the IGMP group (and, as
a result, the NLB cluster MAC address).
When the arp-mac-disparity multicast-igmp command is configured on the
VLAN, ARP entries appear in the output of the command show arp like this:
Examples To enable support for MS-NLB in unicast mode on interface vlan2, use the
following commands:
awplus#
awplus(config)#
awplus(config-if)#
C613-50102-01 REV C
C
OMMANDS
configure terminal
interface vlan2
awplus#show arp
IP Address MAC Address
10.100.0.56 0100.5e7f.0038
configure terminal
interface vlan2
Command Reference for x510 Series
AlliedWare Plus™ Operating System - Version 5.4.6-1.x
arp 10.10.1.100 010e.11ff.2222
Interface
vlan200
arp-mac-disparity unicast
Port Type
igmp-group dynamic
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