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White Rabbit Switch - Software
Commit 7974fc67 authored by Paul Boven's avatar Paul Boven Committed by Adam Wujek
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doc/wrs-user-manual: Update information about SFP matching 

Signed-off-by: 's avatarAdam Wujek <dev_public@wujek.eu>
parent b2556faa
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doc/wrs-user-manual.in
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......@@ -1842,13 +1842,21 @@ parameter itself.
@subsection SFP name matching
Each time you plug an SFP transceiver into any of the @sc{wrs} ports, it has to be matched
against @t{dot-config} entries specifying timing parameters for the supported transceivers.
The matching algorithm reads from the SFP its vendor name (@i{vn}), part number (@i{pn}) and vendor
serial (@i{vs}). Then, SFP parameters are compared with values stored in
@t{CONFIG_SFP@i{xx}_PARAMS} @t{dot-config} entries:
against @t{dot-config} entries specifying the timing parameters and wavelength for the
supported transceivers.
The matching algorithm reads from the SFP its vendor name (@i{vn}), part number (@i{pn}), vendor
serial (@i{vs}) and TX wavelength in @t{nm}. Note that it only reads the integer part (i.e. rounded down)
of the TX wavelength, as shown by @t{wrs_sfp_dump}. Then, these SFP parameters are compared
with the values stored in the @t{CONFIG_SFP@i{xx}_PARAMS} @t{dot-config} entries:
@itemize
@item
The @i{wl_txrx} field in the @t{CONFIG_SFP@i{xx}_PARAMS} must contain the transmit and receive
wavelengths of the SFP in @t{nm}, as integers, separated by a '+'. The TX wavelength as
reported by the SFP is matched against the tx entry (first number) in the @i{wl_txrx} entry. If these do
not match, then this @t{CONFIG_SFP@i{xx}_PARAMS} entry cannot match against this SFP.
@item
The first try is to match a complete set of SFP identifiers (@i{vn}, @i{pn} and @i{vs}).
For the remaining parameters, first a match against all the vendor SFP identifiers
(@i{vn}, @i{pn} and @i{vs}) is attempted.
@item
If a corresponding entry cannot be found, the match is limited to @i{vn} and @i{pn} and
compared only with those @t{dot-config} entries that do not specify any vendor serial.
......@@ -1861,24 +1869,25 @@ To understand better the operation of SFP matching algorithm, please see below s
@itemize @bullet
@item
@t{CONFIG_SFP00_PARAMS="vn=Axcen Photonics,pn=AXGE-3454-0531,vs=AX12390009629,
tx=0,rx=0,..."}
tx=0,rx=0,wl_txrx=1490+1310"}
This entry can be matched only to one SFP transceiver as it specifies full set of parameters,
including the unique vendor serial number (@i{vs}).
@item
@t{CONFIG_SFP01_PARAMS="vn=Axcen Photonics,pn=AXGE-3454-0531,tx=0,rx=0,
wl_txrx=1310+1490"}
wl_txrx=1490+1310"}
This entry may be matched only to all SFPs with vendor name "Axcen Photonics" and
part number "AXGE-3454-0531", with exception to the SFP that was already matched to
This entry may be matched only to all SFPs with vendor name "Axcen Photonics",
part number "AXGE-3454-0531" and a TX wavelength of 1490 nm, with exception of the SFP
that was already matched to
the previous entry @t{CONFIG_SFP00_PARAMS} (with vendor serial defined).
@item
@t{CONFIG_SFP02_PARAMS="pn=AXGE-3454-0531,tx=0,rx=0,wl_txrx=1310+1490"}
@t{CONFIG_SFP02_PARAMS="pn=AXGE-1254-0531,tx=0,rx=0,wl_txrx=1310+1490"}
This entry will be matched to all SFPs with part number "AXGE-3454-0531",
that were not matched by any of the entries listed earlier.
This entry will be matched to all SFPs with part number "AXGE-3454-0531" and TX wavelength of
1310 nm, that were not matched by any of the entries listed earlier.
@end itemize
......@@ -1900,7 +1909,14 @@ and long fibers, you should provide an appropriate value of alpha,
according to laboratory measures of your fiber type. The
@t{CONFIG_FIBER@i{xx}_PARAMS} items are parsed as a list of
comma-separated assignments, so you can specify multiple
wavelength pairs. The accuracy of your value depends on the length
wavelength pairs. Each entry has the form @t{alpha_1310_1490=2.6787e-4}, where the numbers
are again the wavelength in integer @t{nm}. Note that only one value of alpha is needed for
each pair of wavelenghts, the switch will calculate the corect value of alpha when the wavelenghts
are switched around.
Example: @t{CONFIG_FIBER00_PARAMS="alpha_1310_1490=2.6787e-04"}
The accuracy of your value depends on the length
of the fiber link. For a 10km fiber (100us round-trip) you need to know
alpha up to 1e-7 if you want the related uncertainty to be
less than 10ps.
......
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