3750 SMI and EMI images?

Discussion in 'Cisco' started by thefunnel, Nov 19, 2005.

  1. thefunnel

    thefunnel Guest

    Hi all,

    Would someone mind clarifying how the SMI and EMI images work on 3750
    switches? I have read the following in the 3750 software installation

    The Catalyst 3750 switches are shipped with either of these software
    images installed:

    · Standard multilayer image (SMI), which provides Layer 2+ features
    (enterprise-class intelligent services). These features include access
    control lists (ACLs), quality of service (QoS), static routing, and the

    Hot Standby Router Protocol (HSRP) and the Routing Information Protocol

    (RIP). Switches with the SMI installed can be upgraded to the EMI.

    · Enhanced multilayer image (EMI), which provides a richer set of
    enterprise-class intelligent services. It includes all SMI features
    plus full Layer 3 routing (IP unicast routing, IP multicast routing,
    and fallback bridging). To distinguish it from the Layer 2+ static
    routing and RIP, the EMI includes protocols such as the Enhanced
    Interior Gateway Routing Protocol (EIGRP) and the Open Shortest Path
    First (OSPF) Protocol.

    We have been purchasing both EMI and SMI switches for use in the same
    stack. We have been using the "arc copy-sw" command to synchronise
    IOS versions across the switches.

    Does this mean we have been copying EMI images onto SMI switches? Or
    vice versa? Am I confusing images with IOS versions? Are they the same

    Many thanks,
    thefunnel, Nov 19, 2005
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  2. From what I've seen on the newer Cisco switch hardware, the SMI and
    EMI (and Advanced) images are all identical, even though the software
    download area makes it sound like they are all different. I've binary
    diff'ed some of the files and they are the same.

    Looks like there is some cookie file on the switch that controlls
    which license you really have, and you are fine copying around the
    images like you have been.
    Doug McIntyre, Nov 19, 2005
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  3. thefunnel

    DigitalVinyl Guest

    We've changed from SMI to EMI on switches and all we did was download
    the correct file. The hardware is the same, just SIGNIFICANT
    licensing costs for the extra software capabilities.

    DiGiTAL_ViNYL (no email)
    DigitalVinyl, Nov 19, 2005
  4. I've tested this out for the same thing for a 3560 and a 2950T in the
    lab, and they don't increase their license values after doing so.

    As I've said, I've binary diffed the files presented for download for
    the different licenses for these two particular ones without any
    difference what-so-ever.

    OOTH, I was successful to do this on one of the older switches in a lab
    situaton once. I don't remember the specific model, it was the first
    model to offer the SMI vs. EMI licenses vs. the older
    desktop/enterprise license model.

    So, perhaps one model still lets you, but in general, the newer models
    do not let you.
    Doug McIntyre, Nov 20, 2005
  5. thefunnel

    DigitalVinyl Guest

    This was a 3750-12G model, probably purchased early 2005. We needed
    to implement multicast routing features and the commands were not
    present in the SMI image. We loaded the EMI and had access to them. We
    may have used a tar file to do the upgrade, that includes an INFO file
    and the htmls. So perhaps that was important in some way.

    DiGiTAL_ViNYL (no email)
    DigitalVinyl, Nov 20, 2005
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