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I am trying to send a packet to several nodes from my PC through a border router. The nodes and the border router are developed using Contiki. The problem is that I cannot send multicast messages because the border router does not forward them to the nodes. Is there any way to solve this?

Edit: I am using IPv6 for routing and the multicat packets are sent using UDP protocol. Moreover the border router interfaces are Ethernet or SLIP (connection to the PC can be made both ways) and 6lowpan over 802.15.4 (connection with the nodes).

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Likely you'll have to include a protocol like IGMP—assuming you're using IPv4. The standard multicast in the Internet Protocol ends at router boundaries for a good reason. Unfortunately, I have no Contiki experience to help you out with the specifics of the implementation.

However you solve the issue, you'll need to establish proper boundaries for the mutlticast. IGMP does that by creating multicast groups that cross router boundaries.

The IPv6 protocol for similar purposes is MLD—Multicast Listener Discovery.

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  • I am using IPv6. Is there any similar protocol? As you say multicast ends at router so I cannot communicate with the nodes because the router does not forward the multicast direction and my application is useless without multicast functionality. – JuanMa Mar 7 '17 at 10:46
  • @JuanMa yes there is. I'll put it in my answer. Please add that IPv6 information to your question as well. If you update your question you'll also lose the edit marker by Aurora ;) – Helmar Mar 7 '17 at 15:54

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