Chapter 19: DOCSIS Set-top Gateway Configuration
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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Configuring IP Forwarding for Basic Mode DSG
Caution: This section does not apply to advanced DSG configuration. If IP forwarding is configured in such a way that it
conflicts with any advanced DSG tunnels, the IP forwarding configuration takes precedence over the advanced DSG tunnel
configuration. This could disable the advanced DSG tunnel.
IP forwarding for basic DSG tunnels is statically configured. There are two different kinds of forwarding used for basic DSG
tunnels:
Destination IP address is Multicast and Destination MAC address conforms to RFC1112
Destination IP address is Multicast and Destination MAC address does not conform to RFC1112
DSG forwarding is configured using IGMPv2 or IGMPv3 when the destination IP of the DSG tunnel is a multicast address.
The following commands configure static membership for the DSG tunnel:
configure interface cable-downstream <slot>/<port>[<.subif#>] ip igmp static-group
<dsgTunnelDestIP> [source <dsgTunnelSrcIp>]
Note: IGMPv3 must be used when a source IP address is specified with the static group configuration.
If the destination IP address of the basic DSG tunnel is multicast and the MAC address does not conform to RFC1112, the
following command is used in addition to the static group which replaces the RFC1112 destination MAC address with the
specified destination MAC address.
configure ip multicast mac-ip <dsgTunnelDestIP> <dsgTunnelDestMAC>
Show Commands
The following commands are used to display the IGMP group membership including those statically joined:
show ip igmp groups [detail]
show ip route
show ip mroute