Do I need Enhanced Multilayer Image for Control System LAN

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Mar 26th, 2009
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I am designing a network for a refinery and the vendor I am working with is suggesting the EMI image is required for routing within the LAN "no connections to the internet" I do not see a need for the Enhanced Image and feel the Standard image should suffice. What I'd really like to get my hands on is some type of checklist that qualifies most or all of the primary reasons to utilize one or the other?

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Edison Ortiz Thu, 03/26/2009 - 07:57
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Gary,


You haven't mentioned the type of switch in question.


Cisco provides an interactive engine that allows you to compare images. Please visit this URL: http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp


SMI is known as 'IP Base' and EMI is known as 'IP Services'.


HTH,


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Edison.

garymack61 Thu, 03/26/2009 - 09:03
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The Switches to be used are the 3750G-12S-E, a redundant set to take advantage of HSRP. The network model is based off the Honeywell Level 1 and Level 2 network for their Fault Tolerant Ethernet (FTE) design that basically uses broadcasts packets to communicate every nodes status and allows honeywell to boast of a 1 millisecond recovery time within the redundant system - (network design attached) The FTE technology is over 10 years old and was based on the STP protocol as I understand from reading their patents and researching. The control network itself is highly secure and has no direct connections or routes to the internet, thus the reason I question the need for the Enhanced Image. Data being routed to networks above level 2 will be passed to the DMZ for internal plant access and will have to traverse level 4/5 routers to get to the outside world. I see the EMI as more of an internet IP protocol necessity that would not provide much in the way of supporting the basic level 2 routing requirements.



Edison Ortiz Thu, 03/26/2009 - 10:26
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SMI image (a.k.a IP Base) should be sufficient for this task.


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garymack61 Thu, 03/26/2009 - 10:37
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ediortiz - I appreciate your time and thank you for your comments.


Sincerely,


garymack61

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