Archive for December 2011
Well, I was taking a SonicWall class last week, and finally got around to taking the certification test earlier this evening. It was a 60 question exam, and I passed the exam with an 88%, not perfect but the passing score was an 80% plus I didn’t want to go back and double check all the questions I marked. Since the voucher code I was given provided me with 3 attempts I was not feeling the pressure. It wasn’t a very complex exam it had a mixture of basic IPSec, NAT, VPN functionality, but still not as in depth as what is covered in the CCNA/CCNA: Security exam if you’ve debugged a few IPSec VPN’s on a Cisco device you can definitely read the logs on a SonicWall device. The other half of the test was all related to SonicWall functionality its routing, security, & wireless features. If you’ve got some good security experience and can navigate your way through a SonicWall like the back of the your hand then I’d say go for it. Of course considering my existing number of certifications I have yet to find out if adding SonicWall to my credentials will pay off, only time will tell.
Now back to the 642-642 QoS Exam (Which I was studying for in the middle of the SonicWall class), let’s see if I can take & pass this exam by the end of the year!
Well, since I covered the CBWFQ in my last post I think it’s only natural I jump into the configuration of yet another QoS configuration Low Latency Queuing or LLQ. LLQ simply builds off the CBWFQ, let’s look at the configuration from my last post concerning CBWFQ:
Now let’s configure LLQ:
See the difference? Notice the priority keyword, that is what configures LLQ. Not too complicated right? Now what does this priority command really do for us, well it creates a low latency queue for traffic that needs to be transmitted before other type of data. So if there is data in the low latency queue when does the data in the other queue’s get transmitted, easy when the low latency queue is empty or when the low latency queue exceeds its specified amount of bandwidth. The low latency queue is also policed by the bandwidth we have allocated it. If the low latency queue ever exceeds the amount of bandwidth it has been allocated it will drop the packet and move to another queue.
Below is a flow chart from the QoS Exam Guide explaining how the LLQ works: