Enabling Ip Multicast Routing - HP A6600 Configuration Manual

First-hop router—The router that directly connects to the multicast source is called the "first-hop
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router".
Querier—The router that sends multicast traceroute requests is called the "querier".
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Introduction to multicast traceroute packets
A multicast traceroute packet is a special IGMP packet, which differs from common IGMP packets in that
its IGMP Type field is set to 0x1F or 0x1E and its destination IP address is a unicast address. The
following types of multicast traceroute packets are available:
Query, with the IGMP Type field set to 0x1F,
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Request, with the IGMP Type field set to 0x1F, and
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Response, with the IGMP Type field set to 0x1E.
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Process of multicast traceroute
The querier sends a query to the last-hop router.
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After receiving the query, the last-hop router turns the query packet into a request packet by adding
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a response data block—which contains its interface addresses and packet statistics—to the end of
the packet. The last-hop router then forwards the request packet via unicast to the previous hop for
the given multicast source and group.
From the last-hop router to the multicast source, each hop adds a response data block to the end of
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the request packet and unicasts it to the previous hop.
When the first-hop router receives the request packet, it changes the packet type to indicate a
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response packet, and then sends the completed packet via unicast to the querier.
IP multicast does not support the use of secondary IP address segments (multicast can be routed and
forwarded only through primary IP addresses, rather than secondary addresses, even if configured on
interfaces). For more information about primary and secondary IP addresses, see Layer 3— IP Services
Configuration Guide.

Enabling IP multicast routing

Before you configure any Layer 3 multicast functionality, you must enable IP multicast routing.
Enabling IP multicast routing for the public network
To do...
1. Enter system view.
2. Enable IP multicast routing.
Enabling IP multicast routing in a VPN instance
To do...
1. Enter system view.
2. Create a VPN instance and
enter VPN instance view.
Use the command...
system-view
multicast routing-enable
Use the command...
system-view
ip vpn-instance vpn-instance-name
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Remarks
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Required.
Disabled by default.
Remarks
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