Browse list lag time.

[Christopher R. Hertel]

Moving this to samba-tech, and also CCing the jCIFS list as this
information will be of interest there, too. 

> > And now I have a question (Maybe better for samba-technical?).. How
> > does the client get the netbios name of the lmb? Node status request?
> > Does every browser-capable server answer these?
> 
> Under the MS model it doesn't need the netbios name of the LMB!
> 
> Instead MS clients do a "get backup list request" to the LMB name and

That would be the ..__MSBROWSE__. name, yes?

> that returns a list of netbios names that are BMBs (backup master
> browsers). This list usually includes the LMB netbios name, but it
> doesn't have to. The client then picks one. 

How does the client pick one?  Is there a formula for this?

> Samba doesn't do this. Instead we do a status request. We should fix
> that at some stage :)

So, back to the question of how many minutes (max) out of date a Network 
Neighborhood can be.  The original word problem went thuslike:

- If a station gets switched off, the LMB on that subnet will wait three 
  12-minute cycles before removing the services from the browse list.  At 
  worst (i.e., the station was switched off immediately following it's 
  last browser update) the time delay will be 3*12=36 minutes.

- The LMB syncronizes with the DMB every 15 minutes. Once the DMB has the
  updated information, it has to send it out to other LMBs.  So the 
  worst-case on that is 2*15=30.

- Adding up the two above values gives us the 66 minute value.

...but...

- The client can get its Network Neighborhood listing from a Backup Master
  Browser instead of the Local Master Browser.  It might take 66 minutes 
  for a remote shutdown to be reflected in the LMB's list, but it can take
  an additional 15 minutes for the LMB to update the BMBs.  That's where 
  Paul Nelis got 81 minutes.

- Finally, I'm curious to know how often a client does a NetServerEnum
  call.  Does this happen only when needed, or is there a refresh period?
  If the Network Neighborhood is only refreshed on demand, then can we 
  say that there is no theoretical upper limit to how out of date it is? 

Fun.

Chris -)-----

-- 
Christopher R. Hertel -)-----                   University of Minnesota
crh at nts.umn.edu              Networking and Telecommunications Services