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[IDD #YCX-842647]: Please Advise Bilateral or Unilateral restriction of TOC LDM RadarII feed to TPC

Hi Gini,

re:
> NWS  has question in regard to NEXRAD2 data from TOC LDM Server to TPC
> LDM Client:
> 
> Tropical Preciction Center (TPC) wants to draw NEXRD2 data for a
> sliding subsets of 25  sites --depending on weather conditions--
> from the TOC LDM server.
> Telecommunications Operations Center (TOC) wants to avoid  any
> on-going  reconfiguration issues of its NEXRD2 LDM server  due to
> any TPC sliding selection  of the productids
> 
> Both TOC and LDM  need to conserve network bandwidth and ensure the
> whole CONUS NEXRD2 data set  is NOT being sent from TOC to TPC and
> at most only the 25 sites of the superset required by TPC.
> 
> TOC server  is version  ldm-6.4.4 at cluster IP 140.90.85.102
> TPC client is version  ldm-6.5.5 at  IP 140.90.176.123
> 
> 
> Is it correct that if  TOC allows all NEXRD2 to TPC but TPC requests
> only a subset of the productIDs then TOC LDM server will not send
> the entire NEXRD2 to TPC ?

Yes, this is correct.

> Can you advise the the best strategy ?  Should we restrict by
> productID at Server side, at Client side, or at both ?

Restricting the feed through the allow on the server side insures that
only the data you want sent to the TPC will be sent.  As your opening
comment indicates that you understand, however, it puts the onus on the
TOC for determining the volume of data that can be sent.

Having the TCP craft appropriate request lines puts the onus on them to
request _only_ the data that they need/want.  If someone at the TPC changes
the request to ".*", then the TOC LDM will send all of the data _if_ its
allow is wide open (i.e., allow ".*").

There is, however, a happy medium approach:

- determine the full set of stations that the TPC could possibly want and
  set the allow on the TOC machine to only allow those stations only

- have the TPC request just the stations they want

In this approach, not all of the data that could be sent would be sent if 
someone
at the TPC accidentally changed their request to ".*".

> Can you provide the allow and/or request statements that the TOC
> server and the TPC client would require given the inclusive list of
> all the sites that TPC would be interested in requesting as follows:
> 
> kakq
> kamx
> kbox
> kbro
> kbyx
> kcbw
> kclx
> kcrp
> kdix
> kdox
> kevx
> kgyx
> khgx
> kjax
> klch
> klix
> kltx
> klwx
> kmhx
> kmlb
> kmob
> kokx
> ktbw
> ktlh
> tjua

My recommendation:

TOC allow:

allow NEXRAD2 name.of.tpc.machine 
"(KAKQ|KAMX|KBOX|KBRO|KBYX|KCBW|KCLX|KCRP|KDIX|KDOX|KEVX|KGYX|KHGX|KJAX|KLCH|KLIX|KLTX|KLWX|KMHX|KMLB|KMOB|KOKX|KTBW|KTLH|TJUA)

TPC request:

request NEXRAD2 
"(KAKQ|KAMX|KBOX|KBRO|KBYX|KCBW|KCLX|KCRP|KDIX|KDOX|KEVX|KGYX|KHGX|KJAX|KLCH|KLIX|KLTX|KLWX|KMHX|KMLB|KMOB|KOKX|KTBW|KTLH|TJUA)"
 name.of.toc.machine

Comment:

As I alluded to above, I would expand the TOC allow to include all stations 
that the TPC could possibly want.
Presumably, this list is a smallish subset of the set of all Nexrad stations.

Finally, you should always test the patterns used in allow or request lines.  
This is easily done from
the downstream site using the LDM 'notifyme' utility.

Example:

1) assuming that there is an allow for all Nexrad stations in the upstream's 
~ldm/etc/ldmd.conf file,
   the downstream could run the following to verify that they would get just 
the stations that
   they want:

<as 'ldm' on the TPC LDM machine>
cd ~ldm
notifyme -vxl- -f NEXRAD2 -h name.of.the.toc.ldm.machine -p 
"(KAKQ|KAMX|KBOX|KBRO|KBYX|KCBW|KCLX|KCRP|KDIX|KDOX|KEVX|KGYX|KHGX|KJAX|KLCH|KLIX|KLTX|KLWX|KMHX|KMLB|KMOB|KOKX|KTBW|KTLH|TJUA)"

2) assuming that the upstream machine has a restricted allow, the downstream 
could use 'notifyme'
   to see which stations they are allowed to get:

<as 'ldm' on the TPC LDM machine>
cd ~ldm
notifyme -vxl- -f NEXRAD2 -h name.of.the.toc.ldm.machine

Testing one's request/allow pattern using 'notifyme' greatly speeds the process 
of getting exactly
what is wanted/needed -- it eliminates trial and error.

> thanks
> Gini Galvin
> NWS/OCIO/TOC/TSB
> 301 713 0882 ext 176
> 
> 
> 
> Colin J McAdie wrote:
> > Gini,
> > Let's do whatever makes the most sense.  I have attached a list of 25
> > radars that represents our "universe."   If these were on the TOC
> > allow list, we envision requesting the subset that we needed with our
> > client.    We would keep shifting down the coast as conditions
> > dictated, dropping off radars and adding them by editing the client,
> > without having to bother you to do anything.   There would not be any
> > need to change anything on the allow list, on your side.
> > As far as the best strategy, it really depends on the bandwidth.   I
> > am assuming (correct me if I am wrong) that if TOC allows all NEXRD2
> > products, that we would be streaming down the whole CONUS all the
> > time, rather than just the list of 25.   Bandwidth is kind of a
> > sensitive issue because we really take a beating during a landfall.
> > We want to avoid pegging the needle on the line we're using.
> > Colin
> >
> > Virginia Galvin wrote:
> >> Colin
> >>
> >> ldm support pages show  restriction of data by product id but only
> >> covered examples with either the server or client restricting
> >> products -- not both.
> >>
> >> I think  TOC and TPC will be making more work for themselves by
> >> restricting products on both server and client -- however, as we
> >> discussed this might provide more assurance that the estimated data
> >> flow (for 20+ sites/1-3GB/day) would not be exceeded if for some
> >> reason TPC ldm client did not restrict its requested products.
> >>
> >> If both sides restrict products then TPC will need to coordinate with
> >> TOC to make minor changes, eg., addition or deletion of one or two
> >> sites, and TOC will need to stop and restart and test configuration
> >> which will affect other TOC LDM clients.
> >>
> >> To give TPC  maximum flexibility for minor changes and to reduce
> >> impact on TOC operations it  makes more sense to let the TPC restrict
> >> the product ids requested and TOC to allow all NEXRD2 products to TPC.
> >> If you  have TPCs list of sites I can plug into the productID EREs
> >> restriction example below and request LDM Support to check syntax.
> >>
> >> Gini
> >>
> >>
> >> TOC restricts NEXRD2 products
> >> TOC ldm server at  ldm-6.4.4 wants to allow TPC ldm client at 6.5.5
> >> to receive only 20 or so sites  (sites used for example only)
> >> request NEXRD2  ".*" 140.90.113.165
> >>
> >>     allow NEXRD2 ^140\.90\.176\.123$
> >>     ^L2-BZIP2/(KAAA|KBBB|KCCC|KDDD|KEEE|KFFF|KGGG|KHHH)
> >>     allow NEXRD2 ^140\.90\.176\.123$
> >>     ^L2-BZIP2/(KAAA|KBBB|KCCC|KDDD|KEEE|KFFF|KGGG|KHHH)
> >>     allow NEXRD2 ^140\.90\.176\.123$
> >>     ^L2-BZIP2/(KAAA|KBBB|KCCC|KDDD|KEEE|KFFF|KGGG|KHHH)
> >>
> >> TPC restricts NEXRD2 products
> >> TPC ldm client at ldm 6.5.5 wants to receive only these sites  from
> >> TOC ldm server at ldm 6.4.4
> >>
> >>     request NEXRD2 ^L2-BZIP2/(KAAA|KBBB|KCCC|KDDD|KEEE|KFFF|KGGG|KHHH)
> >>     140.90.85.102
> >>     request NEXRD2 ^L2-BZIP2/(KAAA|KBBB|KCCC|KDDD|KEEE|KFFF|KGGG|KHHH)
> >>     140.90.85.102
> >>     request NEXRD2 ^L2-BZIP2/(KAAA|KBBB|KCCC|KDDD|KEEE|KFFF|KGGG|KHHH)
> >>     140.90.85.102
> >>
> >>
> >>
> >>
> >>
> >>
> >>> Gini,
> >>> We are running ldm-6.5.5
> >>> Colin
> >>>
> >>> Virginia Galvin wrote:
> >>>> Colin
> >>>> What ldm are you running?
> >>>> TOC is running ldm-6.4.4.
> >>>> gini
> >>>>
> >>>>
> >>>>
> >>>> Virginia Galvin wrote:
> >>>>> To:  Alison Krautkramer and Colin McAide
> >>>>>
> >>>>> Re:  Request for Radar II feed to TPC.
> >>>>>
> >>>>> TOC would like to  implement a test of  requested Radar II feed to
> >>>>> TPC on Thursday 9/20/07  before 16Z (noon EDT).
> >>>>>
> >>>>> The feed will be coming from 140.90.85.102 ( a cluster address for
> >>>>> 2 servers). TPC  may want to verify with their network staff the
> >>>>> reachability of 140.90.85.102 and allowance for port 388 traffic.
> >>>>>
> >>>>> TOC will need  TPC assistance  during the test on Thursday to
> >>>>> verify feed from each of the two TOC LDM RII servers. (Feed will
> >>>>> always be supplied by the cluster IP, 140.90.85.102 but TOC will
> >>>>> switch  RII  server activity from primary to secondary system and
> >>>>> back again and ask TPC to confirm feed of the data from each
> >>>>> server taking control of that IP.)
> >>>>>
> >>>>> TOC will  allow any data from the IP(s)  TPC specifies using the
> >>>>> allow format :
> >>>>>
> >>>>>     allow   ANY    ^999\.99\.99\.999$
> >>>>>
> >>>>> or  TPC can supply an allow statement format for TOC to test
> >>>>>
> >>>>>
> >>>>> Please give me a call to discuss this in detail
> >>>>> Thanks
> >>>>>
> >>>>> Virginia Galvin
> >>>>> Computer Specialist
> >>>>> 301 713 0882 x 176
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> 
> 

Cheers,

Tom
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Ticket Details
===================
Ticket ID: YCX-842647
Department: Support IDD
Priority: Normal
Status: Closed