用ping来检查网络时,如下 Reply from 119.75.218.45：bytes=32 time=28ms T

用ping来检查网络时,如下 Reply from 119.75.218.45：bytes=32 time=28ms TTL=55
1.每次都是固定发送32字节的数据包吗?
2.time=28ms,这个time的大小说明什么?（网速快慢,路径长短）
3.TTL这个生命周期具体是个生命概念,如何体现?

1、默认32 ,可以在命令行修改
2、网速快慢
3、TTL是IP协议包中的一个值,它告诉网络,数据包在网络中的时间是否太长而应被丢弃.TTL的最初设想是确定一个时间范围,超过此时间就把包丢弃.由于每个路由器都至少要把TTL域一,TTL通常表示包在被丢弃前最多能经过的路由器个数.当记数到0时,路由器决定丢弃该包,并发送一个ICMP报文给最初的发送者.
再问： 32字节的数据包如何修改呢，能具体给个例子吗，以及运行结果吗
再答： C:\Documents and Settings\Administrator>ping/? Usage: ping [-t] [-a] [-n count] [-l size] [-f] [-i TTL] [-v TOS] [-r count] [-s count] [[-j host-list] | [-k host-list]] [-w timeout] target_name Options: -t Ping the specified host until stopped. To see statistics and continue - type Control-Break; To stop - type Control-C. -a Resolve addresses to hostnames. -n count Number of echo requests to send. -l size Send buffer size. -f Set Don't Fragment flag in packet. -i TTL Time To Live. -v TOS Type Of Service. -r count Record route for count hops. -s count Timestamp for count hops. -j host-list Loose source route along host-list. -k host-list Strict source route along host-list. -w timeout Timeout in milliseconds to wait for each reply. C:\Documents and Settings\Administrator>ping -l 128 127.1 Pinging 127.0.0.1 with 128 bytes of data: Reply from 127.0.0.1: bytes=128 time