Figure 1. Data terminal equipment layer model (Redrawn from the IEEE Std 802.3, 1998 Edition)
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100BaseT/1000BaseT fast link pulses
The link information is encoded in a special pulse train known as the fast link pulse (FLP) burst. The FLP builds on the LIT pulse used by 10BaseT devices as a heartbeat pulse to the link partner at the opposite end of the link. The LIT was redefined as the normal link pulse (NLP). As shown in Figure 2 , the NLP is the 10BaseT link integrity test pulse, and the FLP is a group of NLPs. Each pulse is 100 ns in width.
Figure 2. FLP and NLP comparison
By Rich Hernandez
http://www.dell.com/content/topics/global.aspx/power/en/ps1q01_hernan?c=us&cs=555&l=en&s=biz
13.2 Fast Link Pulse
ตอบลบAuto-Negotiation takes place using Fast Link Pulse (FLP) signals. These signals are a modified version of the Normal Link Pulse (NLP) signals used for verifying link integrity, as defined in the original 10BASE-T specifications. The FLP signals are generated automatically at power-up, or may be selected manually through the management interface to an Auto-Negotiation device.
http://www.ethermanage.com/ethernet/100quickref/ch13qr_3.html
ไม่รู้เกี่ยวรึเปล่า เพราะมีการพูดถึง test link pulse ลองดูใน...
ตอบลบI try with my poor head to understand the integrity link test pulse.
(1) The link test pulse (e.g. for 10BaseT) is not repeated on the other
ports of the hub when this one receives it. Is it correct?
(2) Is someone can explain me in a few words why there is sometimes NLP
(normal link pulse) and why there is sometimes FLP (fast link pulse)? Is NLP
still exists?
ref:
http://www.tomshardware.com/forum/19724-42-about-link-test-pulse