Table 199: IPv6 DHCP Snooping Statistics Fields
Field
Description
Interface
The interface associated with the rest of the data in the row.
MAC Verify Failures
The number of DHCPv6 messages that were dropped because the source MAC
address and client hardware address did not match. MAC address verification is
performed only if it is globally enabled.
Client Ifc Mismatch
The number of packets that were dropped by IPv6 DHCP snooping because the
interface and VLAN on which the packet was received does not match the
client's interface and VLAN information stored in the binding database.
DHCP Server Msgs Received
The number of DHCPv6 server messages (ADVERTISE, REPLY, RECONFIGURE,
RELAY-REPL) that have been dropped on an untrusted port.
Clear Counters (Button)
To reset the statistics to zero for one or more interfaces, select each interface
with the data to reset and click
Clear Counters
. You must confirm the action
before the entry is deleted.
Click
Refresh
to refresh the page with the most current data from the switch.
Configuring IGMP Snooping
snooping is a feature that allows a switch to forward multicast traffic intelligently on the switch.
Multicast IP traffic is traffic that is destined to a host group. Host groups are identified by class D IP
addresses, which range from 224.0.0.0 to 239.255.255.255. Based on the IGMP query and report
messages, the switch forwards traffic only to the ports that request the multicast traffic. This prevents
the switch from broadcasting the traffic to all ports and possibly affecting network performance.
A traditional Ethernet network may be separated into different network segments to prevent placing
too many devices onto the same shared media. Bridges and switches connect these segments. When a
packet with a broadcast or multicast destination address is received, the switch will forward a copy into
each of the remaining network segments in accordance with the IEEE MAC Bridge standard. Eventually,
the packet is made accessible to all nodes connected to the network.
This approach works well for broadcast packets that are intended to be seen or processed by all
connected nodes. In the case of multicast packets, however, this approach could lead to less efficient
use of network bandwidth, particularly when the packet is intended for only a small number of nodes.
Packets will be flooded into network segments where no node has any interest in receiving the packet.
While nodes will rarely incur any processing overhead to filter packets addressed to un-requested group
addresses, they are unable to transmit new packets onto the shared media for the period of time that
the multicast packet is flooded. The problem of wasting bandwidth is even worse when the LAN
segment is not shared, for example in Full Duplex links.
Allowing switches to snoop IGMP packets is a creative effort to solve this problem. The switch uses the
information in the IGMP packets as they are being forwarded throughout the network to determine
which segments should receive packets directed to the group address.
Global Configuration and Status
Use the IGMP Snooping Configuration and Status page to enable
snooping on the switch and
view information about the current IGMP configuration.
Configuring Switching Information
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