A router uses its () to detemine where to forward the packets.

The Internet is a () system of interconnected computer networks that use the standard Internet protocol suits(TCP/IP) to serve several billion users worldwide。

IPv6 is currently in growing deployment around the world,() Internet address registries (RIRs) began to urge all resource managers to plan rapid adoption and conversion.

() switching was invented in the late 1960s for data communications.

科技工作者应有正确的方向和目的，应以（）作为科技活动的出发点和归宿。

科技工作者探求真理，向真理靠近所必须坚持的思想路线是（）。