[300-115] CCNP Switch - here we go

negru_tudor

So after doing my CCNP Voice about 1.5 years ago I (sadly!) got transitioned into a role dealing mainly with application support with a mix of networking and security here and there but voice to a lesser degree.

However, since as of late I've been more involved in network troubleshooting and design/re-design, I've considering tackling the CCNP R&S track to further consolidate & broaden my knowledge in this area.

After a thorough CCNA review (took me about 1.5 months to get back in the saddle and go through all the topics covered in the CCNA syllabus I studied) I decided to tackle switch first. In this regard, I've acquired the OCG books for SWITCH and TSHOOT.

My strategy here is to go through the SWITCH OCG book first, get the concepts and knowledge down then go through the switch-related side of things from the TSHOOT book..I found out the hard way that this is a very good approach from my CCNP Voice studies.

I'm going to try to lab everything out in GNS3 using the latest IOU-L2 images out there and try to supplement with real gear as much as I can. However, based on my CCNP Voice experiences, you can pretty much get away with over 90% of the stuff just by using VMware and GNS3.

My purpose for this thread is to try and track my progress going forward and maybe keep some sort of repository of "lessons learned"/"gotchas" from studying this stuff if I ever need to come back and review.

So, CCNP R&S, here I come baby!

koz24

Good luck man. IIRC L2 IOU cannot do private vlans or L3 etherchannels. But maybe the new images can. Practice it anyway with notepad or something.

negru_tudor

koz24 wrote: »

Good luck man. IIRC L2 IOU cannot do private vlans or L3 etherchannels. But maybe the new images can. Practice it anyway with notepad or something.

thanks gonna need some o' that

Well, they seem to work as of late (tried the L3 Etherchannel myself)

https://www.gns3.com/discussions/private-vlan-l3-ethchannel-and-v

..so it's now more convenient than ever to study these things I guess. Stackwise, yes, might pose a problem but I'll get around it somehow. I've Boson NetSim as well, not sure if that emulates stackwise or not - guess I'll find out down the road.

negru_tudor

Well, things do go into a lot more detail. Had me lost at the TCAM bits initially. Also thought that that SDM GUI is back on the syllabus until I saw it stands for something else in CCNP :P ..Cisco and their abbreviations..gotta love it.

Cisco Inferno

Good luck!

I've also heard about poking into the TSHOOT material to solidify your knowledge.

CBT Nuggets all the way right? Jeremy Cioara is of Romanian descent too if you didnt know haha. (cioara = crow)

negru_tudor

Cisco Inferno wrote: »

Good luck!

I've also heard about poking into the TSHOOT material to solidify your knowledge.

CBT Nuggets all the way right? Jeremy Cioara is of Romanian descent too if you didnt know haha. (cioara = crow)

Thanks:)

Yeap, using CBT and Kevin Wallace's stuff as well. Am going wider on this one. For CCNA Voice & CCNP Voice I stuck to mostly just 1 video courses source but this time I'm trying to mix/match to get the best of both worlds (Jeremy's enthusiasm and analogies with Kevin's more methodical approach). I do think Jeremy's grandpa or great grand father was Romanian so yeah, was a fun fact to find out when I first heard about it

bodokid

I have the same impression that Jeremy has some romanian blood in his veins About PVLAN and Etherchannels : https://www.gns3.com/discussions/private-vlan-l3-ethchannel-and-v are working now in GNS3 !!

Bafta!!!

negru_tudor

bodokid wrote: »

Bafta!!!

Multumesc !!

Was also very pleased to see how far GNS3 has come recently with IOU and IOSv-L2 and IOSv-L3 support...now all we need is time to study this stuff properly

negru_tudor

I've made it up to Chapter 4 (out of 18 Chapters in the OCG). So far, it's mostly rehashes from the CCNA topics. However, several areas which I suspect I'll need to come back and revisit again would be:

- TCAMs and/or CEF: might not be a mandatory focus for this exam but I somehow feel it's very important overall for L3 "wirespeed" switching

- LLDP: am fairly comfy with CDP as I've used it in day-to-day tasks and throughout CCNP Voice studies but haven't used LLDP that much

- Err-Disabled states: so far only ran into these things while doing "switchport security" stuff in CCNA R&S and had to "shut / no shut" ports to recover

- ISL: not sure how much the exam focuses on this but I still need to read up on it

- SFPs and all the wacky 10GBASE-LRM stuff: I understand what these do if I look up a tech sheet and where you'd use them etc. but man, I feel that I'll go crazy trying to memorize distances etc.

...so yeah, don't want to get ahead of myself but so far, so good..(and this probably jinxed everything to hell :P )

shortstop20

Don't bother memorizing distances for fiber, but you should know when you need single mode vs. multimode.

negru_tudor

@shortstop20: Thanks. Usually that's what I do (skip these things and just look up the spec sheet when needed) but I've been through several Cisco exams now and saw some similar stuff being asked in the exam questions (things you wouldn't / shouldn't bother knowing by heart).

I take it you already took the SWITCH exam and sharing this as advice?

negru_tudor

Funny how things change over time..

CCNA: VTP is cool, STP is cool
CCNP switch: VTP is awful, STP the same..everything moves to L3 interfaces

..as Yoda would put it, you must unlearn what you have learned

negru_tudor

....and a major "gotcha" with L2-IOU and L3 Etherchannels.. got the channel "up" & "up" fine via the config, but when trying to pass traffic from one switch to the other, one of the switches would C-R-A-S-H!.

..turns out you HAVE to disable CEF on the switch ("no ip cef") so that L3 Etherchannel can actually pass traffic between the peering switches without crashing one of them.

Legacy User

negru_tudor wrote: »

Funny how things change over time..

CCNA: VTP is cool, STP is cool
CCNP switch: VTP is awful, STP the same..everything moves to L3 interfaces

..as Yoda would put it, you must unlearn what you have learned

Moving all switch uplinks to L3 does sound like a good idea but that will require a lot of tuning for access layer Switches set up for stub routing to avoid any black holed traffic. From a design standpoint for example if overlooked ALL of the network traffic can traverse an undesired L3 device that wasn't configured as a stub router at a remote site because it "looks" like the best path from point A to B.

L3 works fine from the DL to the core setup as P2P connections with distribution lists, etc to filter out anything not needed. From the Access layer to the Distribution switches RSTP (if capable) works great because the transition is under a couple of seconds. If a network is still running legacy STP then its time for a refresh!

negru_tudor

well, I'm 6 chapters into the OCG (out of 22 ) and I'm not that impressed with the way concepts are presented.

I wasn't expecting anything CCNA-like (holding your hand etc.) but even explanations for more deep topics have mistakes (considering STP costs for 1 Gpbs interfaces of 19 when they should be 4 etc.) and seem to be too long-winded and/or exposed in a more "lyrical" rather than "technical" manner.

Having a more structured / "bulletpoint"-like layout might have helped more..guess that's where taking notes & videos come into play.

Legacy User

Do you have any access to the skillsoft videos? I am currently working on my CCNP Switch as well which I have been dragging my feet through.. I read through the chris bryant book which is more like an overview tells you what you need to know but not much in depth information as to the "why". I only looked through the OCG for something I was unsure about so I can't say I have any real complaints with it.. For videos I am using kevin wallace and skillsoft ccnp videos. Kevin wallace videos are a good for a quick explanation on how it works before you start reading it.

I personally really really enjoy the skillsoft videos which I get free access since I am a WGU alumni. That video series thoroughly goes over the blueprint which totals out to 25hrs of training for just the CCNP SWITCH unlike the INE series while is informative keeps mentioning for certain topics that it was talked about during the CCNA training video and to please reference that, which aggravates me since I don't have access to that.

Also, not sure of your environment (enterprise, msp, var, isp etc). I work in an enterprise setting full blown multi campus design and really grasping the design and concepts of the ccnp switch has been much easier since I basically reverse engineer my network layer by layer as a real world reference to understand the "why" behind things.

If you have that much visibility of your companies network you can work from the access-layer up to the core layer issuing different show commands to get a real view so while gaining a better understanding of the ccnp switch topics you will also gain deeper understanding of your network as well.

negru_tudor

Nope, i don't but I should manage with what I have for now (CBT, Kevin Wallace, OCG and Boson). I was merely sharing my overall thoughts on the OCG so far. FLG might be better but i don't have that so these will have to do

EDIT: we've a collapsed core design in our HQ office with 2 branch sites connecting back to it in the region I'm in. Not very complex but it does the job but we do have customers who span large networks. However, since I was more on the voice side of things I didn't get the chance to mess around in those areas too much, more on voice communication servers, voice gateways, SBC etc. but with the current shift in direction, I'm getting there..

negru_tudor

Note to self: turn off DTP on trunk links ("switchport nonegotiate").

Reason: DTP slows down STP convergence

Best practice (as per Jeremy):

- hardcode trunk config (switchport mode trunk)
- disable DTP negotiation (switchport nonegotiate)

... was used to hardcode the trunk settings (mode and encapsulation) alright but for some reason I constantly overlooked disabling DTP. Live & Learn

Legacy User

Regardless of the size of your network I'm sure there is still a hierarchy to it whatever you have access to. Issue show commands in the switches from the different layers to understand what the switch is doing. Its always cool getting those Aha! moments. Learning it and seeing it in real time really hardens your knowledge in my opinion.

Also, when you see something that conflicts best practice in your network or unsure why its configured that way raise the question to a senior engineer why it was configured that way. They may have an answer to why they needed to issue a bandaid fix which is great for learning or you may have pointed out a misconfiguration error which will make you look good.

negru_tudor

dmarcisco wrote: »

Regardless of the size of your network I'm sure there is still a hierarchy to it whatever you have access to. Issue show commands in the switches from the different layers to understand what the switch is doing. Its always cool getting those Aha! moments. Learning it and seeing it in real time really hardens your knowledge in my opinion.

Also, when you see something that conflicts best practice in your network or unsure why its configured that way raise the question to a senior engineer why it was configured that way. They may have an answer to why they needed to issue a bandaid fix which is great for learning or you may have pointed out a misconfiguration error which will make you look good.

Thanks, been in the field for some time to get a general feel of how to go about odd configs and/or map a basic network out so obvious stuff at this point. Also don't have much to prove to anybody at this point aside from myself

Legacy User

lol true just was doing some knowledge transfer ;P hey if it doesn't help you it may help the next guy who's trying to make sense of the big picture when working on a certification lol.

negru_tudor

dmarcisco wrote: »

lol true just was doing some knowledge transfer ;P hey if it doesn't help you it may help the next guy who's trying to make sense of the big picture when working on a certification lol.

no harm done it's good info nonetheless and valuable but I feel that if you'd be going for CCNP level stuff and you're still at a loss on how to "figure out" the basics of a network (not the advanced stuff MLS, QoS, wacky ACLs etc.) then you need to go back and review CCNA like immediately!

Best of luck in your studies

Funny thing is I actually went for switch first because I like routing more but I have a lot more drive now so might as well use the momentum to get the less fun one out of the way.

negru_tudor

Managed to get up to the "Protecting STP Topologies" (Chapter 8 )so far.

Also got a slight boost in studies seeing how we had to deploy a new access layer switch for expanding our office space.

Still have 2 more STP chapters left (current one and the RSTP & MST one) after which I'll be doing a full review up until this point, taking notes and doing additional labs from Boson and the CCNP Switch Lab Manual 2nd Edition.

joeljosue

In what rhytm are you studying?

1 Chapter a week? or 5 day?

I´m about to restart my studies for the CCNP Switch, and all contribuition are welcome.

negru_tudor

joeljosue wrote: »

In what rhytm are you studying?

1 Chapter a week? or 5 day?

I´m about to restart my studies for the CCNP Switch, and all contribuition are welcome.

It depends on what work is like and how much spare time I have outside of work.

First chapters went by fast - felt more like a CCNA rehash - and since I'm fresh out of a long CCNA review, things went fast aside from some stuff (TCAM, LLDP, ISL etc.) that wasn't in the CCNA syllabus.

There's 22 chapters in the OCG.

I'm 8 chapters in now (aprox. 1 third of the way).

So far, I went through the printed version of the OCG, read the concepts, took notes inside the book and did some rough flashcards.

I also watched both CBT Nuggets and Kevin Wallace's videos on all the topics form the OCG that I went through.

I plan on going back to chapter 1 now, review everything and take more structured notes in a separate notebook, do BOSON NetSIM labs and labs from the CCNP Switch Manual (2nd Edition) to have all these concepts sink in deep.

Once I've done this, I'm going to move on the next bunch of chapters and do the same thing until I finish with the OCG.

Then, once I've went through everything and I'm confident that I have the concepts down and can lab them up, I'm going to crack open the TSHOOT book and go through all the SWITCH-related topics there & try to get the finer nuances down.

negru_tudor

So still hammering away at this although I was a bit set back study-wise due to a VoIP project at work.

Recently managed to get a good deal on INE courses as well so I have been going through the SWITCH-related vids and so far they're very very good. I just realized what a poor job the OCG does at describing / teaching MSTP ..darn..

negru_tudor

Seems like the latest Packet Tracer is able to accept "sdm" related commands ("show sdm prefer") and even allow simulate changing the sdm template on a 3560 MLS switch. Can't do that with IOUs nor Boson's devices.

negru_tudor

VTP/VLAN "tricks" from the lab guide:

-> vlans can be put into "suspended" mode and VTP will mirror this state across all switches in the VTP domain (suspended = traffic is discarded); done in vlan configuration mode with "state suspend"

-> vlans can be put into "shutdown" mode and VTP will NOT replicate the state on any of the domain switches - change is only local; done in global configuration mode via the "shutdown vlan x" command. The stat will come up as "lshut" (locally shutdown).

...good commands to know (if you're running VTP that is :P )

and some STP/MST ones:

-> Root Guard: best configured on your STP domain boundaries to guard topology. Never a good idea to configure it inside the STP domain's links

-> MST0/IST cost to ROOT will show as 0 (the External Root Path Cost) when the CST_Root is actually the current region's IST_Master.

This reported cost would only increase from 0 on links leading to other regions (boundary links). Basically with IST, each region will act like one single bridge (to neighboring regions) so inside a region, the ERPC (external root path cost which actually is displayed in the "show spanning-tree root" command) is 0.

But right beneath the "path cost 0" line, there's an "internal cost" field which actually shows the internal cost to the Regional IST_Master.

negru_tudor

Currently made it as far as Ch. #15 in the OCG (IP SLA) out of 22.

I've labed this topic up a couple of times during my CVOICE studies but mainly used udp-jitter probes then to measure MOS, delay, jitter and packet loss. The R&S track though seems to focus more on the icmp-echo ones with an emphasis on using these combined with object tracking which I think is very cool that we can leverage this sort of mechanism.

Managed to stage and lab all of the topics so far but feel I will have to revisit and focus more on:

- NTP authentication
- SNMPv3 and SNMP security
- DHCPv6 and DHCPv6 Lite
- SPAN and RSPAN (next study section)

I can't say I've used these too much in the past so definitely need to commit more time to labbing them over and over again until I feel comfortable.

negru_tudor

While reading up on IP SLA, I stumbled across the Embedded Event Manager which basically allows you to use EEM to monitor the state of a tracked object (which in turn monitors an SLA probe) and generate Syslog messages if the object goes Down or comes back Up. Not on the CCNP blueprint but very cool stuff to have at hand - increases the appeal of being able to use IP-SLA and object Tracking to keep a close eye on the network.

For example, if IP-SLA probe 1 runs an icmp-echo test and Object 5 would be monitoring this probe, the config for pushing Syslog messages on probe/object failures would look like this:

!
track 5 ip sla 1 reachability
!
event manager applet Track_My_SLA
event track 5 state down
action 1 syslog msg "Your IP_SLA probe is dead"
!

..and this will basically trigger syslog &/or SNMP messages to let the admin know what's going on.

I really like this feature. Onto RSPAN now!

NEODREAM

Hope your progress is going well. Following this has motivated me to begin my studies for my CCNP:Switch!


Good luck and continue on!