链路层上可靠的虚跨步交换支持技术

在高性能互连网络设计中,缩短通信延迟一直是设计的首要目标之一。虚跨步交换技术是一种降低延迟的有效手段,但是在有限的输入缓冲区条件下,在链路层上实现高效可靠传输具有一定的挑战性。本文提出了一种可靠的低延迟链路层设计方法,可实现对虚跨步的有效支持,减少了报文在中间路由器上的延迟。该方法结合了报文格式设计、发送方管理和接收方管理。通过在报文头中加入额外的校验码,有效地保护了报文头中的信息,提高了链路的容错能力;通过链路级重传,减少了端到端重传引起的时间、协议开销;通过对接收处理逻辑,尤其是接收缓冲区管理的有效实现,避免了可能出现的缓冲区溢出以及流控失效问题。

A Design of the Reliable Link Layer for Virtual Cut-Through Switching

One of the primary objects in designing high performance interconnection networks is to reduce the communication latency.Virtual cut-through is an effective latency-tolerant technique.But under the condition of limited input buffering,it is a challenge to implement the reliable link layer with the high speed.We present a method to conquer this problem and support virtual cut-through switching with link layer,reducing the unnecessary buffering in an intermediate node.It combines the efforts of packet format,sender manager and receiver manager.Firstly,an extra cyclic redundancy code is included in packet header to protect the information;secondly,a link level retry is provided to reduce the time and protocol overhead involved in the end-to-end retry;thirdly,with the effective implementation receiver, and especially the input-buffer,we avoid the buffer overflow and the flow control corruption.