发明授权
US5719862A Packet-based dynamic de-skewing for network switch with local or central
clock
失效
具有本地或中央时钟的网络交换机的基于分组的动态去偏移
- 专利标题: Packet-based dynamic de-skewing for network switch with local or central clock
- 专利标题(中): 具有本地或中央时钟的网络交换机的基于分组的动态去偏移
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申请号: US649114申请日: 1996-05-14
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公开(公告)号: US5719862A公开(公告)日: 1998-02-17
- 发明人: Raymond K. Lee , Alex Chi-Ming Hui
- 申请人: Raymond K. Lee , Alex Chi-Ming Hui
- 申请人地址: CA San Jose
- 专利权人: Pericom Semiconductor Corp.
- 当前专利权人: Pericom Semiconductor Corp.
- 当前专利权人地址: CA San Jose
- 主分类号: G06F1/10
- IPC分类号: G06F1/10 ; H04J3/06 ; H04L12/56
摘要:
A network switch uses a simple switch core of analog MOS transistor switches. The switch core is surrounded by many media-access controllers (MAC's) which buffer the data through the switch core. Multiple connections through the switch core may be made between different pairs of MAC's. Just one signal path through the switch core is needed per connection as a second path through the switch core for the clock is not needed. The clock is not encoded with the data, so PLL's are not needed for clock recovery. Data skew is instead measured for each packet transmitted through the switch core. A start flag is added to the packet by a source MAC as a packet header before being transmitted through the switch core. The start flag is a unique sequence which is detected by the destination MAC and triggers measurement of the data skew of the received start flag to the local clock. The measured data skew is then used to compensate for the rest of the packet. Because dynamic de-skewing is performed for each packet, any packet from any source MAC can be received. This allows freedom in MAC placement and enables construction of larger switches. The switch may have the MAC's physically separated from each other by greater distances since clocks can be locally generated. The clocks are independent from each other except for having the same frequency.
公开/授权文献
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