The basic mechanism that Auto-Negotiation uses to advertise a device's
abilities is a series of link pulses which encode a 16 bit word, known
as a Fast Link Pulse (FLP) Burst. An FLP Burst is composed of 17 to 33
link pulses which are identical to the link pulses used in 10BASE-T to
determine whether a link has a valid connection (sometimes referred to
as Normal Link Pulses or NLPs.) FLP Bursts occur at the same interval
as NLPs, 16.8ms. An FLP Burst has a nominal duration of 2 ms. Figure 2
shows the nominal timing of FLP Bursts.
FLP Burst Timing
An FLP Burst interleaves clock pulses with data pulses to encode a 16
bit word. The absence of a pulse within a time window following a
clock pulse encodes a logic zero and a pulse within the time window
following a clock pulse encodes a logic one.
5.1 Auto-Negotiation on Alternate Media
since link pulses do not directly translate onto fiber,
an alternate coding scheme could be defined to replace the link
pulses. The algorithm and Link Code Word encodings would all remain
the same.
Fast Link Pulse (FLP) Burst.
A group of no more than 33 and not less than 17 10BASE-T
compatible link integrity test pulses. Each FLP Burst encodes
16 bits of data using an alternating clock and data pulse
sequence.
link pulse.
Communication mechanism used in 10BASE-T and 100BASE-T networks
to indicate link status and (in Auto-Negotiation equipped
devices) to communicate information about abilities and
negotiate communication methods. 10BASE-T uses Normal Link
Pulses (NLPs), which indicate link status only. 10BASE-T and
100BASE-T devices equipped with Auto-Negotiation exchange
information using a Fast Link Pulse mechanism which is
compatible with 10BASE-T.
10BaseT link test pulses
The 10BaseT standard includes a link test mecha-nism
to ensure network integrity. In the absence
of network traffic, a 100 nanosecond (ns) heartbeat unipolar
(positive only) pulse is sent every 16 milliseconds (ms) within a
range of +/- 8 ms. The link test pulse is sent by the transmitters
of all 10BaseT media attachment units (MAUs) between the data
terminal equipment (DTE) and the repeater.
A link fail condition is entered if the receiver does not receive a
packet or a link test pulse within 50-150 ms. The link fail condition
disables the data transmit, data receive, and loopback functions. The
link test pulses continue to be transmitted and received during the
link failure. The link is reestablished when two consecutive link test
pulses or a single data packet have been received.
PowerSolutions 118
(NLPs).
16 +/-8 ms
17-33 NLPs
2 ms
Link integrity test pulses
FLP burst
NLP
...
Figure 2. FLP and NLP comparison
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"WARNING: Do not look into laser with remaining eye"
No nechci do toho Clocku moc vrtat, ja vim, ze si hrajes s laserem silnejsim nez se slavne povedlo navazat plazmatikum z rubiovych laseru (2W), ale 802.3 ti jasne specifikuje delku kabelaze pro 100BasteTX... no a je tam mimo jine do 100m pro kolizni domenu a 250m na duplex pri cat5 .... Pokud je to ze dvou paru cat3(telefoni drat), tak je to pro 100BaseT4 jeste kapku min.
Mimo jine, ten muj Edimaxik ma taky routovaci tabulku, takze mozna se vyplati i kouknout, co tam mas vlastne nastaveneho nebo skusit i jinou IP adresu, prece jenom dnesni switche uz bezne videj i na routovaci vrstvu ... Nehlede na to, ze si vyhrazuji nektere IP adresy (obvykle z Ckove masky) na konfiguraci.
13.01.2003 v 00:13
