As promised, here are my complete notes on the OECG for ONT. Good luck in your studies.
Finally a CCNP – Now what?
Posted in General Announcements with tags Passed! on July 13, 2009 by GerrenLast Friday, on a bit of a whim, I went ahead and scheduled for ONT for the following day. I’m not sure why I did that really, but it payed off. For all of the spam bots reading this so far, you’ll be happy to know what I have finally completed all 4 CCNP exams and am officially a CCNP!
Now, don’t get me wrong…it was a great feeling. After it was over though (and I’m sure many of you experience this), there’s this feeling of not necessarily emptiness, but of something…it’s hard to describe. You spend all that time studying, labbing, etc., and once you pass, there’s no fanfare (except from my wife which I appreciate), no fireworks go off, no…nothing. My mind automatically thinks “Ok, what’s next?” Is that sick? Some would say so, but I don’t think it’s such a bad thing.
I really can’t decide where I want to go with it next. I like the thought of the CCSP, but do I spend another 6-9 months for an CCNxP cert, or spend some extra time and go straight for the big letters? Anyone?
Either way, it’s a relief that it’s over with, but a bit of a stressor as well. As a side note, I’ll be putting the rest of my notes online sometime soon…from chapters 4-10 of the ONT OECG.
ONT Chapter 4 – Conegstion Management and Queuing
Posted in Notes with tags ONT, Queuing on July 4, 2009 by GerrenAlso available as a PDF here
Introduction to Congestion Management and Queuing
- Congestion occurs when the rate of input to an interface exceeds the rate of output
- Speed mismatch problem – when traffic on a high speed interface enters the router but exits on a low speed interface
- Aggregation problem – when traffic from multiple interfaces aggregates into a single interface
- Tail drop – occurs when buffers fill up and new incoming traffic is dropped
- Default queuing method is FIFO (first in first out)
- Queuing mechanisms consist of hardware and software components
- Hardware queue is called the transmit queue (TxQ)
- If TxQ becomes full, packets are held in the software queue and release to the TxQ based on the queuing mechanism
- TxQ is always FIFO
- Software queuing has a number of queues – one for each class of traffic
- If the software queue is full, the packet is dropped
- If TxQ is full, packet is held in software queue based on it’s class
- Even if a packet is in one of the software queues, it can still be dropped if WRED is applied to that queue
- The IOS determines the hardware queue based on the configured bandwidth on the interface
- You can manually set the queue size with the tx-ring-limit command
Thoughts so far on taking notes in this format
Posted in General Announcements on July 2, 2009 by GerrenI think so far, even though taking this many detailed notes is time consuming, I’m definitely retaining the concepts a lot easier than just reading them…
I’m managing to read/document a chapter in 2 days (between work/wife/etc.) and there are 10 chapters in this OECG. So that puts me at somewhere around the July 20th when I will be finished reading the book. I’ll go back at that point and watch the Train Signal videos on that topics, and hopefully by the 30th, I’ll be ready for my the exam…CCNP, here I come!
ONT – IP Quality of Service
Posted in Exams with tags ONT, QoS on July 2, 2009 by GerrenAlso available as a PDF here
Introduction to QoS
Converged Network Issues Related to QoS
- Acceptable end-to-end delay for VoIP packets ~ 150 to 200 ms
- 4 major challenges/concerns with converged networks
- Available bandwidth
- End-to-end delay
- Delay variation (jitter) – difference in amount of delay
- Packet loss – usually caused by sudden burst or failures
- Available bandwidth
- Maximum bandwidth of a path is equal to the bw of the link with the lowest/smallest bw
- Available bandwidth = MaxBW/Number of Flows
- Possible remedies include:
- Increase link bandwidth – not always beneficial for bursty traffic
- Classify and mark traffic
- Deploy queuing mechanisms
- Use compression techniques
- Link compression
- TCP header compression
- RTP header compression Read more »
ONT – Introduction to VoIP
Posted in Exams with tags 642-845, ONT, VoIP on June 30, 2009 by GerrenAlso available as a PDF here
Introduction to VoIP Networks
Benefits of Packet Telephony
- More efficient bandwidth usage
- Lower transmission and network costs/expenses
- Improved productivity
- Access to new communication devices
Packet Telephony Components
- Phones
- Gateways – Interconnect with other gateways and allow communication between devices that may not be accessible from the IP network. Also responsible for connecting PBX’s to IP networks
- Multipoint Control Units (MCU) – conference calling device that combines the streams from participants and returns the result to each participant
- Application & Database Servers
- Gatekeepers – these provide call routing and call admission control (CAC) services. Call routing resolves a name or number to an IP address. CAC grants permission for a call setup
- Call Agents – handles call routing, address translation, and call setup
- Video End Points
- Digital Signal Processors – convert analog signals to digital signals using different codes
ONT Study Plan
Posted in Exams with tags 642-845, ONT, Study Techniques on June 29, 2009 by GerrenI think that in an effort to do better on the ONT exam, I’ll do some documentation via posts in hopes that it will sink in with me more effectively. I’d like to do a chapter by chapter breakdown using the OECG to start. Maybe like a “terminology” type section, “related protocols” section, configuration notes, and some “gotchas.” Sounds a bit cheesy though…we’ll see what pans out.
Stay tuned…
ISCW Passed!
Posted in Exams with tags ISCW on June 27, 2009 by GerrenwOOt. I passed the ISCW today…not a top-of-the-class kind of score, but passing nonetheless. I’m not generally an overachiever, but I thought I would do better than I did. Don’t get me wrong, I’m happy that I passed, but either way…I still would’ve enjoyed a higher score.
I think that I get caught in up in the people that are posting that they “Got 1000/1000″ — I suppose that there are folks out there that can ace these tests without much effort, but I’ guessing that a lot of people I see posting these kind of messages are brain-dumpers. No disrespect to anyone who has aced a Cisco exam without using dumps of course.
I supposes that I should be proud that I can pass without using dumps, but I would still like to improve my score next tie. Ahhh…oh well, who cares! 3 test down and only ONT to go for my CCNP.
ISCW Performance Anxiety
Posted in Test Taking Strategy with tags ISCW, Testing on June 26, 2009 by GerrenHere’s what I dislike about Cisco exams. You study, and study, and from your experience and past exams, you feel confident that you are ready to tackle that next exam. Exam day rolls around and about halfway through the exam, you realize that you mos definitely were not prepared.
I’ve had that happen twice now, and I’m not sure what the issue is. So, I’m scheduled to take the ISCW tomorrow, and feel very confident on for this exam, but the anxiety of getting there and realizing a few minutes into it that I’m not as ready as I thought, is always frustrating. Very, very frustrating.
Does this happen to anyone else, or is it just me? I know my weak points are as follows:
- PPPoA/E configuration commands
- Some of the IPSec smaller details
- Some parts of AAA, but I’m not sure what!?!
So, I’ll be running through those questions/topics again tonight, and then tomorrow at 1000 is judgement day. If I pass this, it will be 3 down and ONT to go!
