• a 3750 can act as a layer3 switch by adding the “ip routing” command.
• It can automatically route between locally created vlans because it considers them as connected interfaces (given that the SVIs are created).
• on a device, there are 3 types of traffic: control, management, end user.
• Control traffic such as CDP, DTP, PAgP goes through vlan1 between Cisco switches, even if you clear it from trunks.
• By default, native vlan traffic is untagged. But there’s a Cisco command that tells the switch to tag all vlans.
• by default, native vlan = vlan1. If we set the native vlan to vlan100, then vlan100 frames will be untagged on trunks, and vlan1 frames will be tagged.
• SMI: Standard Multilayer Image
• EMI: Enhanced Multilayer Image
• if switch is acting L2, then we should set a Default Gateway on it to make the management vlan reachable remote ; if it is acting L3, it will have routes instead.
• switch and Management vlan
• the management IP address must be reachable from remote
• best practice: use a same subnet to manage all network devices
• on L2 SW: only one SVI is up at a time

First, let’s see if QoS is enabled on the switch: QoS is disabled. We should enable it on global configuration level: If we want to display QoS settings for an interface, we do a show mls qos interface command: At this stage we still did not define trust boundaries. That’s why Trust State and Trust Mode say “not trusted”. And we did not specify whether we’ll trust a device or not. To define trust boundary with auto-qos, we either trust all CoS values coming on the switch interface or we trust CoS values only if an ip phone is connected to the switch port. With auto qos voip trust, we tell the switch to trust CoS on each packet coming on the switch interface: If we want to further limit trust boundary, we can tell the switch to trust CoS values only if a Cisco ip phone is detected on the port: Finally, on a 3550 switch, show auto qos and show auto qos interface give the same output:

Finally, I passed. I feel so happy that two years of discontinuous study and a lot of frustration paid off. I deserve this nice recognition :) Now, I can tell that it takes a LOT of patience, focus and self confident to pass not only this exam, but the whole track. Why? because many guys fall in the trap of cramming questions in order to become CCNP fast. I began the CCNP journey in 2009. I only became CCNP in 2011! Some guys may tell me that I was not serious about my studies. But here are my arguments:

Two days are left before my TSHOOT exam. I feel confident about it since I have a first taste of it. I read feedback given by test takers that it is a a nice experience. I ought to be ready for both scenarios. If I succeed, then I know that all my limiting beliefs about CCNP were false. Then, I’ll know that I was prisoner of my false beliefs. And if I fail, then I should remind myself about all the courageous people in the IT world who spent a lot of money and time in the pursuit of their certs. Either way, I’ll learn something, and that’s my own choice. I made my choice to enhance my career, no matter what the sacrifices are. “Courage is resistance to fear, mastery of fear - not absence of fear” - Mark Twain

I gathered these notes to mentally prepare my Troubleshooting methodology on the exam day:

• Follow the path
• divide and conquer
• Move the problem
• Bottom up
• Top down After watching Kevin Wallace Bull’s Eye videos and INE Tshoot Exam Demo video, the best method is to use a combination of Divide and Conquer-Bottom up/Top Down-Follow the path. There’s not really one single method that will lead to finding where the problem lies.

This is a collection of possible troubleshooting tips I collected over my studies. They are organized by OSI layer:

Enabling Loop Guard on an interface level does not enable it for the whole system. In fact, a “show spanning-tree summary total” is a bit misleading in this case.

To configure loop guard on an interface:

“loop guard default” is disabled because we haven’t issued a “spanning-tree loopguard default”. Easy:

verify that QoS is enabled:

Enable QoS:

At this stage, all interfaces are by default untrusted. This means that any frame with a priority value will be remarked as CoS/IP Precedence/DSCP value = 0.

Trust CoS values of incoming frames. Useful for trunks:

Trust CoS values only if an attached Cisco ip phone exists (conditional trust):

At this stage, the trust boundary moves to the IP phone. Any priority value of any attached PC frames is untrused, thus remarked with priority 0.

In this lab, I learned the following:

• configuring a HSRP group on physical interfaces,
• testing how a PC can reach a remote subnet through a redundant gateway, by configuring its default gateway as the HSRP virtual address,
• testing how the second router becomes Active,
• testing interface tracking.

For interface tracking, at first, I thought there was a problem with the lab. Topology: configure interface tracking and a decrement value: When I shut down ser0/0 on R2, I expected R2 to become Standby router. But reality bites: Then I checked on R3. R3 is still Standby, not Active ! So what’s wrong? Here’s what Cisco says: How Object Tracking Affects the Priority of an HSRP Router

Score is 822. Passing score was 790. It came after four days of reviewing IPv6, Route maps, BGP,… In the beginning of the test I was taking enough time to read and answer the questions. However I lost much time in my first lab simulation. The scenarion wasn’t clear to me. And each time I had to click on the console button to reach a router. And I was not seeing changes in the routing table so it confused me a lot. I began to worry about my score. And I got my second lab simulation. And immediately after, the third. I told to myself: “man, what did I do to Cisco to treat me this way?” So I had almost 38 minutes to do the third lab sim and 32 questions ! Besides, the test supervisor was tearing papers on her desk. And the other guy in the room was complaining about the bug in his exam. I was going to scream. At the end, I was almost flipping through the questions. I finished the test. The test supervisor told me “congratulations!”.