DissectorTable.get("mpls.label"):get_dissector(2097) returns nil

edit

I'm attempting to build my first LUA dissector. Specifically I'm writing something to decode PWE3 ControlWords (RFC4385) in more detail than the default one. The dissector I've written works fine but I need to pass the payload to an ethernet dissector.

https://www.wireshark.org/docs/wsdg_h... 11.3 indicates that this should be possible

In another blog I found I should use a call of the form:

DissectorTable.get("mpls.label"):get_dissector(2097):call(buffer(4):tvb(), pinfo, tree)

But this just gives me LUA errors "attempt to index a null value"

I tried this:

local my_table = DissectorTable.list()

for k,v in pairs(my_table) do
   print(k.." = "..v)
end

Which proved that the Dissector Table has entries

And this :

local my_dissectors = Dissector.list()

for k,v in pairs(my_dissectors) do
   print(k.." = "..v)
end

Which shows:

...
2097 = pw_eth_nocw
...

So I think I must be pretty close.

Any help would be much appreciated

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