Re: [foxboro] FW: FW: More future direction questions.
- From: stan <stanb@xxxxxxxxx>
- To: foxboro@xxxxxxxxxxxxx
- Date: Thu, 13 Oct 2005 14:44:24 -0400
On Thu, Oct 13, 2005 at 01:44:05PM -0400, Johnson, Alex P (IPS) wrote:
> Not sure that this got out.
>
> Regards,
>
> Alex Johnson
> Invensys Systems, Inc.
> 10707 Haddington
> Houston, TX 77063
> +1 713 722 2859 (voice)
> +1 713 932 0222 (fax)
> +1 713 722 2700 (switchboard)
> alex.johnson@xxxxxxxxxxxxxxxx
>
> Re: We used NCNIs and the V7.X switches to replace the FONBEs in our 4
> existing Nodebus segments. Besides allowing us to install V7.X stations,
> this resulted in greatly reducing the traffic on our originally very heavily
> loaded single Nodebus system.
>
> Good. I wish more people took advantage of this V7.x capability.
>
>
> Re: Using an existing Nodebus segment to interface V8.X stations and any
> CP270s to the V6.X/V7.X DCS portion of our system is going to raise the
> Nodebus traffic impact on the Nodebus segment the ATS modules are installed
> in and could likely overload it - it is a big step backwards for us.
>
> I'm not trying to minimize your request. It's not unreasonable, but there
> are reasons we did what we did and I'd like to present them so you can
> understand what we were thinking when we designed a single ATS module as
> opposed to two different ones.
>
> So, here we go...
>
> The various cases are:
>
> 1) Expanding a CBLAN network with a "new" Node of Mesh equipment
> 2) Moving a Node from a CBLAN network
> a) V7.x Nodes
> b) V6.x Nodes
> 3) Expanding a Node on a non CBLAN system
> a) V7.x Nodes
> b) V6.x Nodes
>
> I believe that this is a complete set of cases. Now, I'll tell you how we
> think the equipment fits the cases. As in any system design, loading must be
> calculated to ensure proper operation, but I think we have you covered.
>
> Case 1) Expanding a CBLAN Network
> Add a "bridge node" to the CBLAN Network. This Node consists of a 1x8
> with just a pair of CBLIs and a pair of ATSs in it. CBLI is hosted by
> a V7.x AW and ATS hosted by V8 AW70.
>
> This option allows the "bridge node" to handle all traffic between the
> Mesh and the CBLAN networks. In this configuration, there is considerable
> throughput.
>
> As Nodes are migrated to the Mesh (using ATS), the load here should go up
> and then down to zero.
>
> Case 2.a) - Moving a Node from a CBLAN Network for V7.x Nodes
> Put the ATS and a NCNI into a dedicated 1x8 - This segment handles quite
> a bit of throughput (1000 packets per second). This option is ONLY
> necessary if the CBLAN's segment is overloaded which would be very
> unusual. The disadvantage is the cost and space of the 1x8.
>
> Or
>
> Put the ATS in a relatively unloaded segment hanging from a V7 switch
> usually the one which hold the CBLI. This is the nominal case. We
> believe that the traffic from any one node to the mesh is unlikely to
> overload a Nodebus segment segment since the CBLAN was handling it.
>
> Case 2.b) - Moving a Node from a CBLAN Network for V6.x Nodes
> Put the ATS into a Nodebus segment on where the CBLI was.
> Since the CBLI's segment is functioning, using an ATS will not
> make it worse.
>
> Case 3.a) Expanding a Node on a non CBLAN system under V7.x
> Put the ATS in a relatively unloaded segment hanging from a V7 switch.
>
> This is the nominal case; we are assuming that the Node segmentation
> has freed headroom on the segment.
>
> It is important to note that the traffic isolation is retained
> at both the ATS and the NCNI. That is, the only added traffic
> in the segment holding the ATS is data that is supposed to move
> into the Node. It is highly unlikely to overload a V7.x segment.
>
>
> Case 3.b) Expanding a Node on a non CBLAN system under V7.x
> If you have used FONBEs, replace them with NCNIs (a good idea
> in any case) and add the ATS to the segment that sinks/sources
> most of the data going to the Mesh.
>
> It is important to note that the traffic isolation is retained
> at the ATS. That is, the only added traffic in the Node is supposed
> to move into or out of the Node. This situation is no different
> than adding a CBLI in the "old days."
>
>
>
> So, for larger expansions - and CBLAN replacements - we recommend a "bridge
> node". For V7.x systems, we believe that most customers will have the slot
> space and lightly loaded segments. For V6.x system, we believe that the use
> of the ATS is no worse than the CBLI that was (or would have been) used in
> the "old days."
>
> At the end of the day, we think we made a reasonable decision for the vast
> majority of the installed base.
>
>
> Does this make sense?
>
It does.
However (and perhaps we are atypical), what we have primarily is isolatde
V6 nodes, and V7 nodes. We do have one set of "nodes" that have a LAN, but
i's the only one in the whole mill. In our area we have none at all. So we
will (hopefully) be upgrading V6 systems, and V8 systems to "UNIX on the
mesh", and perhaps as a interem step connecting some of the upgraded
systems to (as yet) un upgraded V6 systems, via ATS.
Perhaps a high perecntage of the existing sites ahve LANS?
--
U.S. Encouraged by Vietnam Vote - Officials Cite 83% Turnout Despite Vietcong
Terror
- New York Times 9/3/1967
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