Specifications

Configuring IP Multicast Routing
Storing IP Multicast Headers
IPC-439
Cisco IOS IP Configuration Guide
To configure an intermediate IP multicast helper, the first hop router and the last hop router must be
configured. To configure the first hop router, use the following commands beginning in global
configuration mode:
After configuring the first hop router, use the following commands on the last hop router beginning in
global configuration mode:
Note On the last hop router, the ip multicast helper-map interface configuration command automatically
introduces ip igmp join-group group-address on that interface. This command must stay on that
interface for the intermediate IP multicast helper feature to work. If you remove the ip igmp
join-group command, the feature will fail.
Storing IP Multicast Headers
You can store IP multicast packet headers in a cache and then display them to determine any of the
following information:
• Who is sending IP multicast packets to what groups
• Interpacket delay
• Duplicate IP multicast packets (if any)
• Multicast forwarding loops in your network (if any)
• Scope of the group
• UDP port numbers
• Packet length
Command Purpose
Step 1
Router(config)# interface type number
Specifies an interface.
Step 2
Router(config-if)# ip multicast helper-map
broadcast
multicast-address access-list
Configures a first hop router to convert broadcast
traffic to multicast traffic.
Step 3
Router(config-if)# ip directed-broadcast
Configures directed broadcasts.
Step 4
Router(config)# ip forward-protocol udp [port]
Configures IP to forward the protocol you are using.
Command Purpose
Step 1
Router(config)# interface type number
Specifies an interface.
Step 2
Router(config-if)# ip directed-broadcast
Configures directed broadcasts.
Step 3
Router(config-if)# ip multicast helper-map
group-address
broadcast-address
extended-access-list-number
Configures a last hop router to convert multicast traffic
to broadcast traffic.
Step 4
Router(config)# access-list access-list-number
{deny | permit} udp source source-wildcard
destination destination-wildcard port
Configures an access list.
Step 5
Router(config)# ip forward-protocol udp [port]
Configures IP to forward the protocol you are using.