socket.setMulticastTTL(ttl)
ttl
<integer>
设置 IP_MULTICAST_TTL
套接字选项。
一般来说,TTL 表示"生存时间"。
这里特指一个 IP 数据包传输时允许的最大跳步数,尤其是对多播传输。
当 IP 数据包每向前经过一个路由或网关时,TTL 值减 1,若经过某个路由时,TTL 值被减至 0,便不再继续向前传输。
ttl
参数可以是 0
到 255
之间。
在大多数系统上,默认值是 1
。
This method throws EBADF
if called on an unbound socket.
ttl
<integer>
Sets the IP_MULTICAST_TTL
socket option. While TTL generally stands for
"Time to Live", in this context it specifies the number of IP hops that a
packet is allowed to travel through, specifically for multicast traffic. Each
router or gateway that forwards a packet decrements the TTL. If the TTL is
decremented to 0 by a router, it will not be forwarded.
The ttl
argument may be between 0 and 255. The default on most systems is 1
.
This method throws EBADF
if called on an unbound socket.