We are really chatting great let us know if you also want to join and learn something from it.!
Anyone interested to work together i have scheduled my attempt and want to discuss rea lab we can do it add me on skype thanks On Fri, Sep 13, 2013 at 1:37 AM, Jason Boyers <[email protected]> wrote: > Can someone block this guy? Not for hijacking a question (which is rude), > but the idea of "rea l lab questions" smells of "actual lab questions" > which is illegal and can be cause for removal of your Cisco certifications > and blocking from obtaining the CCIE. > > Jason Boyers, CCIE #26024 (Wireless) > Blog: netboyers.wordpress.com > > > On Thu, Sep 12, 2013 at 3:47 PM, john arther <[email protected]>wrote: > >> Hi, >> >> If anyone want to pass CCIE WIRELESS LAB then lets discuss on rea l lab >> questions and work on it lets break the lab share the questions and >> solutions >> >> Add me on skype id is (*quad.quad4*) >> >> Thanks >> >> >> On Thu, Sep 12, 2013 at 7:17 PM, Jeen Sern Chew <[email protected]>wrote: >> >>> Thanks Jason and Jeff, >>> >>> It is really confusing, especially with conflicting information out >>> there, like with the hysteresis of being 3 dBm both ways or 3 dBm one and >>> 6dBm the other. >>> >>> Also after calculating, how would you know to increase or decrease the >>> power? >>> >>> The following is how I understand it after some thinking. Some of the >>> figures are just base on real world experience. Say you do a voice survey >>> and place your APs to provide coverage of -67 dBm, 20% overlap and power >>> level of 6-25 mW. The following are the assumptions: >>> - Cisco formula as mentioned above is correct >>> - TPC only decreases power >>> - Hysteresis of 3 dBm >>> - There's another APs see each other rather than by transmitting >>> neighbour message at full power >>> >>> Starts off at level 1 / 100mW. I chose the 3rd highest RSSI to be -50 >>> dBm as that would happen in a voice/high density survey. >>> >>> 20 - (-67 - (-50)) = 20 - (-17) = 37 Hysteresis met, decrease >>> from level 1 / 20dB to level 2 / 17dB >>> 20 - (-67 - (-60)) = 20 - (-7) = 27 Hysteresis met, decrease >>> from level 2 / 17dB to level 3 / 14dB >>> 20 - (-67 - (-70)) = 20 - 3 = 17 Hysteresis met, decrease >>> from level 3 / 14dB to level 4 / 11dB >>> 20 - (-67 - (-80)) = 20 - 13 = 7 Hysteresis met, decrease >>> from level 4 / 11dB to level 5 / 9dB >>> 20 - (-67 - (-85)) = 20 - 18 = 2 Hysteresis not met. Stay >>> at level 5 / 9dB >>> >>> At level 5, it is close to the figures of some deployments out there. >>> >>> Does this calculation make sense? Did I miss anything? If it correct, >>> great! Just need to confirm the assumptions above then. >>> >>> Thanks >>> J Chew >>> >>> >>> On 12 September 2013 01:39, Jeff Rensink <[email protected]> wrote: >>> >>>> This is a frustrating topic indeed. >>>> >>>> TPC will do both power decreases and increases as the environment >>>> changes. But the formula that the document references has a flaw that I >>>> haven't totally reconciled. >>>> >>>> Tx_Max for given AP + (Tx power control thresh – RSSI of 3rd highest >>>> neighbor above the threshold) >>>> >>>> Tx_Max for a given AP should be a static value, correct? It's >>>> supposedly the max possible power that the radio can transmit at for its >>>> chosen channel. The Tx power control threshold is also a static value that >>>> is configurable. So the assumption is that the RSSI of the 3rd loudest >>>> neighbor changes along with the current AP power level. >>>> >>>> If I understand things correctly, the RSSI of the 3rd loudest neighbor >>>> is determined by AP neighbor messages. According to documentation (and I >>>> believe I've tested this myself), neighbor messages are always sent out at >>>> the highest power level and lowest data rate. If that is indeed true, then >>>> the RSSI of the third loudest neighbor is yet another static value >>>> (assuming the environment isn't changing). >>>> >>>> So if none of the variables in the equation are actually variable, the >>>> results of the equation are always the same. That would mean either the >>>> power level would always settle into the max power or the minimum power. >>>> That's not true, so something seems off in the equation or the description >>>> of the variables in the equation. >>>> >>>> My guess is the formula is closer to (Max_AP_Power - Current_AP_Power) >>>> - (3rd_loudest_neighbor - TPC_Threshold) >>>> >>>> A positive result would result in a power increase. A negative result >>>> would result in a power decrease based on the 3 dBm hysteresis. According >>>> to Jerome Henry, it's 3 dBm in both directions in the 7.0.116.0 code. This >>>> assumes that the 3rd loudest neighbor measurement is pretty much always the >>>> same since neighbor messages are always sent as max power. >>>> >>>> So let's say we start at full power on the 2.4 GHz band with a 3rd >>>> loudest neighbor of -60 and threshold of -67. >>>> >>>> (20-20)-(-60-(-67)) = 0-7 = -7 >>>> >>>> -7 is lower than -3, so we drop the power down a level >>>> >>>> (20-17)-(-60-(-67)) = 3 - 7 = -4 >>>> >>>> -4 is lower than -3, so we drop the power once more. >>>> >>>> (20-14)-(-60-(-67)) = 6 - 7 = -1 >>>> >>>> -1 is not lower than -3, so it doesn't change. >>>> >>>> This is a total guess, but it makes more sense to me than the formula >>>> in the documentation. But in the real world, the higher the TPC threshold, >>>> the higher the power levels will be. For instance, a threshold of -60 >>>> would result in higher power levels than a threshold of -70. So if you are >>>> seeing your APs in a particular location settle in at too high or too low >>>> of power levels on average, tweak the threshold as needed. Every increment >>>> of 3 should result in powers going up/down one level on average. >>>> >>>> Jeff Rensink - CCIE #24834 (Wireless, R&S) >>>> Senior Technical Instructor - IPexpert >>>> >>>> >>>> On Wed, Sep 11, 2013 at 9:14 AM, Jason Boyers <[email protected]>wrote: >>>> >>>>> This is a confusing algorithm. Basically, think of it this way: >>>>> >>>>> 1) Three neighbors (at least) hear an APs radio at or stronger than >>>>> the TPC Tx mac value configured under the WLC TPC settings for that PHY >>>>> (802.11a/n or 802.11/b/g/n) >>>>> 2) If #1 is true, then that formula provided is used. >>>>> - The "Tx_Max for given AP" is the maximum transmit power for that >>>>> channel on that particular radio. So, for a 2.4GHz radio, that would be >>>>> 100mW (20 dBm), since that is the maximum for 802.11b. 5GHz is more >>>>> confusing, as it various based on channel and model of AP. >>>>> - The "Tx power control thresh" is the value that is entered in the WLC >>>>> - Note that there is an "hysteresis" value of 3dB for decreasing and >>>>> 6dB (or it was at one point - someone correct me for the current values) >>>>> for increasing the power levels. In other words, the value that is given >>>>> at the end of the formula has to be at least that dB difference from the >>>>> current value in order for a change to occur. >>>>> 3) The AP's radio that is heard by the other three APs is the one that >>>>> is decreased (or it can be increased) if the hysteresis value is exceeded. >>>>> 4) When the formula is run again, it is presumed that the three >>>>> neighbors that are hearing the APs signal are hearing a weaker signal. >>>>> 5) Keep in mind that the algorithm is always from the perspective of >>>>> an AP being heard by 3 or more neighbors, not an AP hearing 3 or more >>>>> neighbors. >>>>> >>>>> Hope this helps. >>>>> >>>>> Jason Boyers, CCIE #26024 (Wireless) >>>>> Blog: netboyers.wordpress.com >>>>> >>>>> >>>>> On Wed, Sep 11, 2013 at 9:36 AM, Jeen Sern Chew <[email protected]>wrote: >>>>> >>>>>> Hey guys, >>>>>> >>>>>> I have a TPC question. >>>>>> >>>>>> There are many conflicting information from different Cisco docs. >>>>>> Some say TPC increase and decrease power, some say TPC only decreases >>>>>> power >>>>>> while CHD increases power. Does TPC do both or only increase? >>>>>> >>>>>> Also Cisco gives the TPC formula of: >>>>>> Tx_Max for given AP + (Tx power control thresh – RSSI of 3rd highest >>>>>> neighbor above the threshold). >>>>>> >>>>>> Is the Tx_Max is the Tx_Max of the specific AP? or Is it the Tx_Max >>>>>> configured on under TPC in WLC? >>>>>> >>>>>> Also, when the calculation is done, I am assuming the power >>>>>> increase/decrease occurs on the neighbour with the third highest RSSI? >>>>>> >>>>>> Thanks >>>>>> >>>>>> Regards, >>>>>> J Chew >>>>>> >>>>>> _______________________________________________ >>>>>> For more information regarding industry leading CCIE Lab training, >>>>>> please visit www.ipexpert.com >>>>>> >>>>>> Are you a CCNP or CCIE and looking for a job? Check out >>>>>> www.PlatinumPlacement.com >>>>>> >>>>>> >>>>> >>>>> _______________________________________________ >>>>> For more information regarding industry leading CCIE Lab training, >>>>> please visit www.ipexpert.com >>>>> >>>>> Are you a CCNP or CCIE and looking for a job? Check out >>>>> www.PlatinumPlacement.com >>>>> >>>>> >>>> >>> >>> _______________________________________________ >>> For more information regarding industry leading CCIE Lab training, >>> please visit www.ipexpert.com >>> >>> Are you a CCNP or CCIE and looking for a job? Check out >>> www.PlatinumPlacement.com >>> >>> >> >> _______________________________________________ >> For more information regarding industry leading CCIE Lab training, please >> visit www.ipexpert.com >> >> Are you a CCNP or CCIE and looking for a job? Check out >> www.PlatinumPlacement.com >> >> > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com > >
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com
