For processing variable length packet, current routers usually separate the packet into the smaller fixed-size one before buffering, or simply provide the packet with a fixed-length buffer.

现代网络设备常采用固定长度缓冲区机制来缓冲可变长度数据包，或采用信元机制将可变长度数据包进行定长化处理后再完成缓冲操作。

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It adds a fixed length of label to the position in front of IP packet, and doesn't need to do any processing.

它在IP数据包前加入固定长度的包头(标签)，不对IP数据包的内容做任何的处理。

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