{"id":538,"date":"2010-03-23T20:01:33","date_gmt":"2010-03-23T20:01:33","guid":{"rendered":"http:\/\/mccltd.net\/blog\/?p=538"},"modified":"2010-05-17T17:23:02","modified_gmt":"2010-05-17T16:23:02","slug":"understand-3550-software-image-smi-and-emi","status":"publish","type":"post","link":"http:\/\/darenmatthews.com\/blog\/?p=538","title":{"rendered":"Understanding the Catalyst 3550 Software Image – SMI and EMI"},"content":{"rendered":"

The 3550 is either a Layer 2 (L2) or Layer 3 (L3) switch, which depends on the software version and feature set that you install.<\/p>\n

The naming conventions for 3550 images begin with either of these:<\/p>\n

\n
\n
\"355o-image-naming-convention\"<\/a><\/dt>\n<\/dl>\n<\/div>\n

The differences between the two are:<\/span><\/p>\n

    \n
  • The SMI image<\/strong> is essentially an L2-only image. \t\tHowever, Cisco IOS Software Release 12.1(8)EA1b includes enhancements to the L2 \t\tfeature set. This release and later SMI releases use the term “Layer2+”. Cisco \t\tIOS Software Release 12.1(11)EA1 adds basic L3 functionality to the SMI image. \t\tThis L3 functionality includes static unicast routing, the Routing Information \t\tProtocol (RIP), and other features. This release and later SMI releases use the \t\tphrase “basic Layer 3 routing features”.<\/li>\n
  • The EMI image<\/strong> is an L2 image in combination with a \t\tfull L3 feature set. This feature set includes:\n
      \n
    • Interior Gateway Routing Protocol (IGRP) and Enhanced IGRP \t\t (EIGRP)<\/li>\n
    • Open Shortest Path First (OSPF) Protocol<\/li>\n
    • Border Gateway Protocol Version 4 (BGP4)<\/li>\n
    • Hot Standby Router Protocol (HSRP)<\/li>\n
    • Protocol Independent Multicast (PIM)<\/li>\n
    • Other advanced \t\t services<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n

      When you upgrade a switch<\/strong>, the switch continues to operate while the new software is copied to flash memory.<\/p>\n

        \n
      • If flash memory has enough space, the new image is copied to the selected switch but does not replace the running image until you reboot the switch.<\/li>\n
      • If a failure occurs during the copy process, you can still reboot your switch by using the old image.<\/li>\n
      • If flash memory does not have enough space for two images, the new image is copied over the existing one.<\/li>\n<\/ul>\n

        Features provided by the new software are not available until you reload the switch. <\/em><\/p>\n

        Although the show version output always shows the software image running on the switch (Layer 2 only or Layer 2 and Layer 3), the model name shown at the end of this display is the factory configuration (SMI or EMI) and does not change if you upgrade the software image. <\/span><\/p>\n

        You can also use the dir filesystem: privileged EXEC command to see the directory names of other software images that you might have stored in flash memory.<\/p>\n

        When you upgrade a switch, the switch continues to operate while the new software is copied to flash memory. If flash memory has enough space, the new image is copied to the selected switch but does not replace the running image until you reboot the switch. If a failure occurs during the copy process, you can still reboot your switch by using the old image. If flash memory does not have enough space for two images, the new image is copied over the existing one. Features provided by the new software are not available until you reload the switch.<\/p>\n

        Although the show version output always shows the software image running on the switch (Layer 2 only or Layer 2 and Layer 3), the model name shown at the end of this display is the factory configuration (SMI or EMI) and does not change if you upgrade the software image.<\/p>\n

        You can also use the dir filesystem: privileged EXEC command to see the directory names of other software images that you might have stored in flash memory.<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

        The 3550 is either a Layer 2 (L2) or Layer 3 (L3) switch, which depends on the software version and feature set that you install. The naming conventions for 3550 images begin with either of these:<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[83,27],"tags":[32],"_links":{"self":[{"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/538"}],"collection":[{"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=538"}],"version-history":[{"count":7,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/538\/revisions"}],"predecessor-version":[{"id":931,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/538\/revisions\/931"}],"wp:attachment":[{"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=538"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=538"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=538"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}