限制多播数据报
我有一个使用多播发送一些 UDP 数据包的应用程序。我查看了网络流量，似乎有很多与使用多播相关的辅助数据包。我不完全理解，但多播本质上会导致更多的网络流量吗？如果是这样，我怎样才能抑制这种情况？
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I have an application that is sending some UDP packets using multicast. I looked at the network traffic and there seems to be a lot of ancillary packets related to using multicast. I don't totally understand it, but does multicast by nature result in MORE network traffic. If so how can I throttle this down?
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除了多播组加入/删除消息之外，不会因发送多播数据而创建任何辅助消息。
然而，NIC、路由器、交换机、打印机等通常都会发送某种多播流量，这可能就是您记录流量时所看到的。
Other than the Multicast group join/remove messages, there are no ancillary messages created from you sending multicast data.
However, NIC's, routers, switches, printers, etc. all usually send some kind of multicast traffic, which is probably what you are seeing if you record the traffic.
简而言之，您需要在客户端节点之间转发流量的网络设备来处理此问题。这些因网络拓扑而异，但通常是：
存在诸如IGMP之类的多播控制协议，但是当然源节点和/或中间节点（例如交换机）必须遵守这些控制协议。
是的，多播会导致更多的网络流量：这就是为什么普通以太网集线器实际上已经消失，而 IEEE 以太网的附加功能（例如 VLAN）如今很流行。
这可能最好在其他一些网站上解决（也许这个 SO 风格的网站 PacketDrop）。
In short, you need the networking equipment that forwards traffic between the client nodes to take care of this. Those vary depending on the network topology but would normally be:
There are multicast control protocols such as IGMP but of course the source nodes and/or intermediate nodes (e.g. switches) must comply to these control protocols.
And YES multicast result in more network traffic : this is why plain Ethernet hubbing is practically extinct and additions to IEEE Ethernet such as VLANs are prevalent nowadays.
This is probably best addressed on some other sites (maybe this SO-style site PacketDrop).
LLC 数据包意味着您的本地网段上可能有子网，但这通常并不意味着额外的数据包。如果您想删除 LLC，您应该将网络更改为完整的 C 类网络。 LLC 或 SNAP 在常规数据包上添加 8 字节标头。
http://ckp.made-it.com/ieee8022.html
LLC packets means you probably have sub-netting on your local segment, usually this doesn't mean extra packets though. You should change the network to a full class C if you want to remove LLC. On regular packets LLC or SNAP adds a 8-byte header.
http://ckp.made-it.com/ieee8022.html