4 Replies Latest reply: Mar 10, 2009 6:16 PM by ryan73 RSS

    Default DTP mode



      I have a question regarding the default DTP mode a port is in and a couple conflicting sources of info.



      The Cisco Press CCIE R&S 3rd ed states on page 45, "Cisco switches default to use DTP desirable mode"



      Yet the 3560 software config guide states on page 12-19 the the default layer 2 interface vlan config is, "switchport mode dynamic auto"



      Could they be talking about different models in the CCIE R&S guide other than the 3560s?



      Thanks in advance.



        • 1. Re: Default DTP mode

          Hi Ryan,


          I am also confused..


          CCIE R&S Guide (3rd Edition ) says that ,"Cisco Switches default to use DTP desirable mode". However no specific model is mentioned here.


          3560 software configuration guide says that, default mode is "dynamic auto"


          CCNP BCMSN Official Exam Certification Guide 642-812, 4th Edition (Page-125) says that the default mode is, "dynamic desirable"


          ICND2 Official Exam Certification Guide 2nd Edition 2007 (Page-30 ), says that "2960 switches default to an administrative mode of dynamic auto".


          For 3550 model, the link



          says that,


          "The default switch-port mode for all Ethernet interfaces is dynamic desirable."



          So...what now ??

          • 2. Re: Default DTP mode
            Scott Morris - CCDE/4xCCIE/2xJNCIE


            The "older" switches wanted to form trunks, hence the dynamic desirable was the default.



            Newer switches are a tad more conservative, so the dynamic auto is now the default.



            Where does the exam fall into this changeout? Unfortunately, I haven't got a clue. I would likely go with the newer "dynamic auto" answer unless proven otherwise. It may also be worthwhile to open a case with CertSupport folks about that. While they will likely not tell you what the answer is (would take the fun away!), they would pass the information along to exam content folks and they could be sure of updates/corrections as needed.



            Cert Support folks are not necessarily technically savvy. So be professional, and give quotes/links to the docs and courseware.



            My two cents.









            • 3. Re: Default DTP mode
              Mohamed Sobair





              It depends on the Switch series, for Instance , the 3550 Switch ports defaults to dynamic-desirable , while on the 3560 Switch ports its default to Dynamic-auto.









              • 4. Re: Default DTP mode

                Thanks for your input guys. I'll try and take it to the cert support staff and see what they come back with. It's never an easy answer is it, but like you said, "that would take the fun away". On with the trip...