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CCNP BCMSN(642-812) Lab – STP(New)
By admin | May 20, 2009
Acme is small export company that has an existing enterprise network comprised of 5 switches;
CORE,DSW1,DSW2,ASW1 and ASW2. The topology diagram indicates their desired pre-VLAN spanning tree mapping.
Previous configuration attempts have resulted in the following issues:
– CORE should be the root bridge for VLAN 20; however, DSW1 is currently the root bridge for VLAN 20.
– Traffic for VLAN 30 should be forwarding over the gig 1/0/6 trunk port between DSW1 and DSW2. However VLAN 30 is currently using gig 1/0/5.
– Traffic for VLAN 40 should be forwarding over the gig 1/0/5 trunk port between DSW1 and DSW2. However VLAN 40 is currently using gig 1/0/6.
You have been tasked with isolating the cause the these issuer and implementing the appropriate solutions. You task is complicated by the fact that you only have full access to DSW1, with isolating the cause of these issues and implementing the appropriate solutions, Your task is complicated by the fact that you only have full access to DSW1, with the enable secret password cisco. Only limited show command access is provided on CORE, and DSW2 using the enable 2 level with a password of acme. No configuration changes will be possible on these routers. No access is provided to ASW1 or ASW2.
Solutions:
|
DSW1#conf t DSW1(config)#spanning-tree vlan 20 priority 61440 DSW1(config)#int g1/0/5 DSW1(config-if)#spanning-tree vlan 40 cost 1 DSW1(config-if)#no shut DSW1(config-if)#exit DSW1(config)#int g1/0/6 DSW1(config-if)#spanning-tree vlan 30 port-priority 64 DSW1(config-if)#no shut DSW1(config-if)#end DSW1#copy run start
Verification： DSW1# show spanning-tree vlan 20 DSW1# show spanning-tree vlan 40 DSW2# show spanning-tree vlan 30 |
That is all, hope to helpful for you. Best Luck for ur BCMSN 642-812 Exam.
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Topics: 642-812 Exam, 642-892 Exam, CCNP | 33 Comments »
33 Responses to “CCNP BCMSN(642-812) Lab – STP(New)”
Comments
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May 21st, 2009 at 6:19 pm
shouldn’t all be done with cost
June 3rd, 2009 at 8:37 am
how sure are you about this configuration
June 9th, 2009 at 10:36 pm
why is the configuration for vlan 30 and 40 different, when the task are alike?
June 12th, 2009 at 8:26 am
I saw this simulation on the 892 composite test today.
Also Pass4Sure has this as the solution for Vlans 30 and 40
Int g1/0/6
sw trunk allow vlan 30
no shut
int g1/0/5
sw trunk allow vlan 40
no shut
end
Now to me tis seems to defeat the purpose of spaning tree alogether. I could not however recall the correct syntax for this solution. The score for the spanning tree section of my test was pretty abysimal so I would think the above post is not correct.
June 25th, 2009 at 5:49 pm
Mr dugger i would like to know whether the solution is correct or not in pass4sure dumps it has been given has
Int g1/0/6
sw trunk allow vlan 30
no shut
int g1/0/5
sw trunk allow vlan 40
no shut
end
is the above correct or else in the post it has been given has separe vlans and the cost
June 15th, 2009 at 8:16 pm
hello
can anyone explain this lab and why (vlan 20 priority 61440)
June 16th, 2009 at 5:55 pm
i have my exam next week pls which of the configuration for vlan 20 and vlan 30 is the correct one
June 20th, 2009 at 9:20 am
I think my answer is correct.
But in the real exam, there will be some little change, you need study carefully.
Good luck!
July 29th, 2009 at 8:45 am
in my test, i resolve the lab with the commands port-priority and spanning-tree vlan 20 priority N.
Although i think kachy’s answer is best for the lab.
Sorry for my english.
July 29th, 2009 at 8:58 am
Tips from this page. Switching section
*Influencing local Root Port election – change the Port Cost.
*Influencing the Root Port of directly connected downstream switch – change the Port Priority.
June 18th, 2009 at 5:18 pm
I had just finish taking up exam for 642-892,
their is a problem in this hotspot it doesnt accept the copy run start, pls if any one encounter the same problem let me know, i have already open a case for this bug.
June 20th, 2009 at 9:30 am
Yeah, this is a problem, but it’s doesnot matter.
July 29th, 2009 at 8:42 am
Yes, i had the same problem about the command *copy run start*.
My teacher say me, *the correct command is copy system:running-config nvram:start-up config*
i fail in my first test, i got 800/803!!!!!
August 6th, 2009 at 4:51 am
I havent taken this test yet so not sure if it will help but this is the latest supported command to replace copy run start:
copy system:running-config nvram:start-up config
June 20th, 2009 at 6:54 pm
why (vlan 20 priority 61440)
June 22nd, 2009 at 2:48 am
because that is the highest possible root id-priority value making sure that the core switch becomes the root.
less is more.
June 22nd, 2009 at 8:33 am
(Why Vlan 20 priority 61440)
The actual question states you have only a lvl 2 access to both the core and DSW2 switches. A show run may not show you details such as spanning tree priorities. So set the priority to the highest ensuring that DSW1 will not be the root for vlan 20.
June 23rd, 2009 at 3:31 am
please why did you use cost 1 for vlan 40 and port priority 64 for vlan 30. And is there any lab on PAgP on the 812 exam. please reply am having my exam this week
July 2nd, 2009 at 3:13 pm
DSW1#conf t
DSW1(config)#spanning-tree vlan 20 priority 61440 <— highest pri wil not be used as ROOT
DSW1(config)#int g1/0/6
DSW1(config-if)#spanning-tree vlan 30 port-priority 64 <—- lowered the port-pri from 128 so this will be used to FW traffic
DSW1(config-if)#no shut
DSW1(config-if)#end
DSW1#copy run start
DSW1(config)#int g1/0/5
DSW1(config-if)#spanning-tree vlan 40 cost 1 > seems like Cisco just wanted to make sure you know how to manipulate STP (using global priority, port-priority, and cost) .. You may configured it with just cost or priority with same effect, but you may not satisfy the exam objective. =)
July 2nd, 2009 at 3:18 pm
oh.. this one.. for the vlan 40..
DSW1(config-if)#spanning-tree vlan 40 cost 1 You can see in the show stp.. output that most cost defaulted to 19 (this means that the line is a ethernet = 100Meg .. but with cost = 1 you mean you got a 1Gig interface.. the best in this case)
(I wonder why that was skipped in my earlier post.. =)
July 7th, 2009 at 3:22 am
Why does Pass4sure use ‘switchport trunk allowed vlan 30’ and ‘switchport trunk allowed vlan 40’ on the gig interfaces instead of using ‘COST’ and ‘PRIORITY’. Is that a legit configuration?
July 8th, 2009 at 11:27 am
hi Pulsw… about your question..
the given solution by p4s I blv is also legit..
coz on the given config .. the gig 1/0/5- 6 are both in trunk mode.. but allowed vlan isnt configured so its passing all vlan in effect..
WITH the given solution you satisfy the question coz you specify the only VLAN you want to pass in Gig 1/0/5 and gig 1/0/6 ..
> Well I think as long as you satisfy the question and get the right output in the show spanning-tree .. your answer will be fine.. =)
July 8th, 2009 at 11:32 am
here is another solution.. a shorter one that is.. I know a friend who passed this exam last month using this solution…
DSW1#conf t
DSW1#spanning-tree vlan 20 priority 61440
DSW1#int gig 1/0/5
DSW1#spanning-tree vlan 30 port-priority 240
DSW1#spanning-tree vlan 40 cost 1
(just ignore the prompt .. just focus on the cmds.. =)
July 9th, 2009 at 1:07 am
many thanks ciscosky
July 9th, 2009 at 1:12 am
what exactly are we looking for with:
DSW1# show spanning-tree vlan 20
DSW1# show spanning-tree vlan 40
DSW2# show spanning-tree vlan 30
thanks..
July 9th, 2009 at 8:31 pm
In the above output, both vlans 20 & 30 are listed as the root bridge and both are forwarding out all ports…
September 20th, 2009 at 11:02 pm
CiscoSky’s example should also works as it is the same principle in terms of adusting port-priority. The original example LOWERS the port-priority of g1/0/6 so that the device at the other end favours that interface for forwarding traffic. CiscoSky’s example does the inverse and INCREASES the priority on g1/0/5 so that the device at the end does NOT favour that interface and instead will use g1/0/6 to forward traffic.
September 20th, 2009 at 11:04 pm
…note that a lower numerical number is actually a preferred one so the lower the port-priority number, the more likely it is to become a forwarding port.
July 10th, 2009 at 2:55 pm
could you tell me which solution is correct
DSW1(config-if)#spanning-tree vlan 40 cost 1
DSW1(config-if)#no shut
DSW1(config-if)#exit
DSW1(config)#int g1/0/6
DSW1(config-if)#spanning-tree vlan 30 port-priority 64
DSW1(config-if)#no shut
DSW1(config-if)#end
or
Int g1/0/6
sw trunk allow vlan 30
no shut
int g1/0/5
sw trunk allow vlan 40
no shut
July 11th, 2009 at 4:41 am
Santosh:
Use the following config which is the original one in the above lab. ‘SWITCHPORT ALLOWED VLAN’ is another way of doing the same thing. I took the exam today and got 100% in the Spanning Tree category…
DSW1#conf t
DSW1(config)#spanning-tree vlan 20 priority 61440
DSW1(config)#int g1/0/5
DSW1(config-if)#spanning-tree vlan 40 cost 1
DSW1(config-if)#no shut
DSW1(config-if)#exit
DSW1(config)#int g1/0/6
DSW1(config-if)#spanning-tree vlan 30 port-priority 64
DSW1(config-if)#no shut
DSW1(config-if)#end
DSW1#copy run start
July 29th, 2009 at 4:54 am
I passed this exam and the example and answer are correct, the above lab
September 4th, 2009 at 9:22 pm
This lab seems to be prominent in the composite. I tried these commands and it did not work. The only thing I missed was the “no shut”
The interfaces are already active, why do you require the “no shut”
September 21st, 2009 at 1:30 am
Some excellent notes on manipulating spanning tree can be found here:
http://www.digivill.net/~binary/ccie/ccie-notes/spanning-tree-notes