40
Gateway(config)# ip dhcp server start-ip
Return the initial IP and maximum number of IP
addresses to default value.
Gateway(config-address-reservation-No.)# no
description
Clear the description for the DHCP reservation
Gateway(config-address-reservation-No.)# no
ip-address
Clear the binding client IP address.
Gateway(config-address-reservation-No.)# no
mac-address
Clear the binding client MAC address.
Show command
Gateway(config)#show ip dhcp server
Show the current IP configurations or verify the
configured IP settings.
Gateway(config-address-reservation-No.)#
show
Show the reservation table of the entry.
4. Configure IGMP function
IGMP, Internet Group Management Protocol, is a communication protocol used to manage the
membership of Internet Protocol multicast groups. IGMP is used by IP hosts and adjacent
multicast routers to establish multicast group memberships. It can be used for online streaming
video and gaming, and allows more efficient use of resources when supporting these uses.
IGMP Snooping is the process of listening to IGMP traffic. IGMP snooping, as implied by the name,
is a feature that allows the Gateway to "listen in" on the IGMP conversation between hosts and
routers by processing the layer 3 packets IGMP packets sent in a multicast network.
When IGMP snooping is enabled in a Gateway it analyses all the IGMP packets between hosts
connected to the Gateway and multicast routers in the network. When a Gateway hears an IGMP
report from a host for a given multicast group, the Gateway adds the host's port number to the
multicast list for that group. And, when the Gateway hears an IGMP Leave, it removes the host's
port from the table entry.
IGMP snooping can very effectively reduce multicast traffic from streaming and other bandwidth
intensive IP applications. A Gateway using IGMP snooping will only forward multicast traffic to the
hosts interested in that traffic. This reduction of multicast traffic reduces the packet processing at
the Gateway (at the cost of needing additional memory to handle the multicast tables) and also
reduces the workload at the end hosts since their network cards (or operating system) will not
have to receive and filter all the multicast traffic generated in the network.
Command
Parameter Description
Gateway(config)# ip igmp
snooping
When enabled, the Gateway will monitor
network traffic and determine which hosts
to receive multicast traffic.
Gateway(config)# ip igmp
snooping immediate-leave
Enable immediate leave function.
No command
Gateway(config)# no ip igmp
snooping
Disable IGMP/MLD Snooping function.
Gateway(config)# no ip igmp
snooping immediate-leave
Disable immediate leave function.
Show command
Gateway(config)#show ip igmp
snooping
Show current IGMP/MLD snooping status
including immediate leave function.
