Multicast - Wikipedia https://en.wikipedia.org/wiki/Multicast
This article is about one-to-many communications. For radio systems, see Point-to-multipoint communication. For broadcasting multiple programs using a single channel, see Multicast channel.
如果你使用的是Linux操作系统，并希望检查你的网络是否支持多播，请对 你的网络接口（通常是eth0）使用ifconfig命令。如果你的网络支持多播，你 会从前面命令的响应中看到MULTICAST属性。
[root@b ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.27.32.114 netmask 255.255.252.0 broadcast 10.27.35.255
ether 00:16:3e:2e:8a:f6 txqueuelen 1000 (Ethernet)
RX packets 6411780215 bytes 1875051735478 (1.7 TiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 4868429492 bytes 1968247596474 (1.7 TiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 59.110.11.24 netmask 255.255.252.0 broadcast 59.110.11.255
ether 00:16:3e:2e:a1:4a txqueuelen 1000 (Ethernet)
RX packets 12463490 bytes 1033900322 (986.0 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 867706599 bytes 332348235879 (309.5 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1000 (Local Loopback)
RX packets 1657927099 bytes 369985658585 (344.5 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1657927099 bytes 369985658585 (344.5 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@b ~]# ifconfig --help
Usage:
ifconfig [-a] [-v] [-s] <interface> [[<AF>] <address>]
[add <address>[/<prefixlen>]]
[del <address>[/<prefixlen>]]
[[-]broadcast [<address>]] [[-]pointopoint [<address>]]
[netmask <address>] [dstaddr <address>] [tunnel <address>]
[outfill <NN>] [keepalive <NN>]
[hw <HW> <address>] [mtu <NN>]
[[-]trailers] [[-]arp] [[-]allmulti]
[multicast] [[-]promisc]
[mem_start <NN>] [io_addr <NN>] [irq <NN>] [media <type>]
[txqueuelen <NN>]
[[-]dynamic]
[up|down] ...
<HW>=Hardware Type.
List of possible hardware types:
loop (Local Loopback) slip (Serial Line IP) cslip (VJ Serial Line IP)
slip6 (6-bit Serial Line IP) cslip6 (VJ 6-bit Serial Line IP) adaptive (Adaptive Serial Line IP)
ash (Ash) ether (Ethernet) ax25 (AMPR AX.25)
netrom (AMPR NET/ROM) rose (AMPR ROSE) tunnel (IPIP Tunnel)
ppp (Point-to-Point Protocol) hdlc ((Cisco)-HDLC) lapb (LAPB)
arcnet (ARCnet) dlci (Frame Relay DLCI) frad (Frame Relay Access Device)
sit (IPv6-in-IPv4) fddi (Fiber Distributed Data Interface) hippi (HIPPI)
irda (IrLAP) ec (Econet) x25 (generic X.25)
infiniband (InfiniBand) eui64 (Generic EUI-64)
<AF>=Address family. Default: inet
List of possible address families:
unix (UNIX Domain) inet (DARPA Internet) inet6 (IPv6)
ax25 (AMPR AX.25) netrom (AMPR NET/ROM) rose (AMPR ROSE)
ipx (Novell IPX) ddp (Appletalk DDP) ec (Econet)
ash (Ash) x25 (CCITT X.25)
[root@b ~]# ifconfig eth0
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.27.32.114 netmask 255.255.252.0 broadcast 10.27.35.255
ether 00:16:3e:2e:8a:f6 txqueuelen 1000 (Ethernet)
RX packets 6411868961 bytes 1875079766643 (1.7 TiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 4868504600 bytes 1968275429713 (1.7 TiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@b ~]#