From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from uplift.swm.pp.se (swm.pp.se [212.247.200.143]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id 9009F21F107 for ; Wed, 24 Apr 2013 04:43:05 -0700 (PDT) Received: by uplift.swm.pp.se (Postfix, from userid 501) id 12D019C; Wed, 24 Apr 2013 13:42:42 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by uplift.swm.pp.se (Postfix) with ESMTP id 082789A for ; Wed, 24 Apr 2013 13:42:42 +0200 (CEST) Date: Wed, 24 Apr 2013 13:42:42 +0200 (CEST) From: Mikael Abrahamsson To: "cerowrt-devel@lists.bufferbloat.net" In-Reply-To: Message-ID: References: <98D3C55B-9D34-495C-AA82-CEDEE1882448@gmail.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) Organization: People's Front Against WWW MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Subject: Re: [Cerowrt-devel] Multicast X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Apr 2013 11:43:06 -0000 On Wed, 24 Apr 2013, Dave Taht wrote: >> I can't find any mention of IGMP proxying in the pimd manual I found. >> ISPs generally do not allow residential customers to talk PIM with the >> network, they expect an IGMP join, which is what an IGMP proxy would >> do. > > Sample application? IPTV. IGMP join is sent from customer device to network which starts sending the multicast stream afterwards. This either requires the IPTV box to have direct L2 connectivity to the ISP network, or it requires whatever home device connects the home to the ISP network to do IGMP proxying from LAN port to WAN port. It then also of course needs to create forwarding entries so the multicast received is forwarded to the LAN. PIM is used within the ISP / enterprise for multicast routing. IGMP is used for end devices who would like to subscribe to a multicast group. A NAT router in a home environment needs to act like a hybrid device, it needs to use IGMP join to get the IPTV stream, but it then needs to forward it as if it was a router. For instance: -- Mikael Abrahamsson email: swmike@swm.pp.se