STUDY STUDY STUDY!

It's 9:42pm. I got home from work at 5:30 and have been studying ever since sans eating a frozen dinner (Salisbury steak). My wife is out with 'the girls' doing dinner so I got a chance to study for a nice long session.

Something VERY sneaky I found about while tooling around on the Cisco 3560. I was trying to get damn Ipv6 working and didn't know about the SDM. This is not the Security Device Manager GUI that some might now, it's different.

Switch Database Modifier.

It's a group of profiles that manages how the switch works. It optimizes the switch to run in different environments. For example if using the 3560 with VLANs (That's what I use them for, don't know about you) a lot then you can use the VLAN profile. For routing functions you could use the routing profile, or . If you want to run IPV6 You MUST reload the switch to get the profile to switch over. Yes, for routing you could just do IP ROUTING, but this is for "Optimizing resources". Once of those trickery items I can see Cisco tossing at me in the lab. I imagine something like:

"Cat1 must be optimized in such a way as to be efficient for the purpose of routing" or something vague like that........great right? lol.

Issue the command sdm prefer ?

There is a list of items, but the one I was looking for was "Dual-ipv4-and-ipv6' which says "Support both IPV4 and IPV6"

This is REQUIRED if you want to use IPV6 on the switch. I was going NUTS trying to figure out what the flying BEEP was happening......until I used that profile. You have to reload in order to make it change though, otherwise it won't work. I can see this costing points on the lab, so I reached out to a buddy who passed the exam and he said "Yep, that will get you and cost you 2 or 3 points as they might tie it to a section"

Awesome. 2 or 3 points is HUGE when passing is 80 and if at the end of the day you add up your points on your task list and think you got it in the bag, things like this will bite you in the ass.

Just imagine all the other little stuff that will come out to haunt you. Flex links are evil, I know I said that before but damn. If you have BGP, OSPF and STP set up and set up flex links without taking into consideration what it will do - BAD THINGS WILL HAPPEN.

1st - it kills your STP.
2nd - it kills your OSPF since routers that are part of the VLAN will no longer form adjacency.
3rd - it KILLS, MURDERS, STRANGLES your BGP since if you have OSPF running and doing any redistribution or maybe you have ibgp rocking out with something else etc -

You just went NUCLEAR BLAST on yourself, costing a couple hours potentially of lost work. All over a simple little innocent flex link.

I will tell you this right now, CCIE = Nothing but a big combat boot that constantly kicks you in the ass. Right when you think you UNDERSTAND - Guess what? YOU DON'T.

That's all I got to say about that, which was a lot but I think I shared what I wanted.

Time for some hang time with the wife for an hour before bed, get up early and start another day in paradise at work, come home study rinse repeate.

Arrrrrrrrrrrrrrrrrrrgh!