bcmsn question

[mikeleahy]

hi
what is the answer to this??

which of the following statements describing trunk links are incorrect...

a - the trunk links belong to a specific vlan
b - multiple trunk links are used to connect multiple devices
c - a trunk link only support native vlan
d - trunk links use 802.10 to identify a vlan
e - the native vlan of the trunk link is the vlan that the trunk uses if that link fails for any reason

with regard to e , is it true or no??

rgds

 

[leedsit]

Hi,

with regards to E, if that link fails... its dead... nothing is going to travel over it! so False...

Lee.

LEEroy
MCNE6,CCNP,CWNA,CCSA,Project+

 

[lerdalt]

I'm interested in what the correct answer is. Giving it just a little thought, I think the least incorrect is D, assuming that is a typo and you mean 802.1q not 802.10

A. Don't like this one because I think of a trunk link as carrying multiple vlans not any one specific.

B. Probably is a true statement, but it seems like it is worded a little funny to me.

C. Really don't like this one thinking of having an ISL trunk, and there isn't a native vlan in ISL.

E. I agree with leedsit. If the link is down...you are out of luck.

Do you know the correct answer?

 

[mikeleahy]

yeah b is supposedly the correct answer but i didnt know about e.

 

[helpdeskdan]

I have found that just because somebody made the question, does not make it a good question. E is wrong. Here is how E could be made correct:

the native vlan of the trunk link is the vlan that the trunk uses if that TRUNK fails for any reason

As I remember, the native vlan originally existed so that it can still communicate with non trunk devices can communicate.

 

[leedsit]

Typical Cisco ambigouty. If my phone line fails... its dead I cannot make a phone call.... if my hard disk fails, its dead, I cannot read any data from it.... If I have a link and its a trunk link, and it fails.... then its dead...

I suppose if the trunking mechanism fails... I.E the end device does not tag packets.... then I guess it could still communicate via the Native vlan using untagged packets....


LEEroy
MCNE6,CCNP,CWNA,CCSA,Project+

 

[mikeleahy]

so what do ye think the answer is

 

[leedsit]

If I was sitting in the exam, I would select C and E....

LEEroy
MCNE6,CCNP,CWNA,CCSA,Project+

 

[mikeleahy]

you have to pick the incorrect ones
a is incorrect for sure as a trunk link belongs to all vlans
c is wrong also
d is wrong as 802.10 is for fddi

b is correct i think , not sure of e

 

[Cluebird]

By "failure" Cisco means the trunk stops trunking and the link reverts to non-trunking behavior. In that case, e is a correct statement. When a trunk link stops trunking, the native vlan is the vlan membership the link will have.

 

[helpdeskdan]

Though this isn't an exam question, that is exactly what I hate about Cisco tests. Some of the questions do not test you on how well you know the material, they test you on how well you can guess the ambiguous meaning. In such a case as this, it would be how well can you guess the Cisco meaning of "failure." Guess the wrong meaning and, even if you completely understand trunking, you will get the question wrong.

 

[mikeleahy]

so is the answer b or r guys

 

[leedsit]

God knows!!!! lol thanks for the Clarification Cluebird.

Well my take is

a - the trunk links belong to a specific vlan
I believe incorrect because they belong to multiple vlans, however with 802.1q, using the Native, could that be construde as Specific?
b - multiple trunk links are used to connect multiple devices
True, Well, if you use two separate trunk to connect two separate switches to a core switch, thats using multiple trunk links to multiple devices
c - a trunk link only support native vlan
Incorrect- They support a Native vlan and other vlans on 802.1q and other vlans on ISL
d - trunk links use 802.10 to identify a vlan
Incorrect - I thought this was a typo and it was meant to be 802.1q, as mentioned before.
e - the native vlan of the trunk link is the vlan that the trunk uses if that link fails for any reason
Correct, if failure means the trunking has failed but the circuit is still up/up.

So in answer I would say the incorrect statements are A,C and D!

but thats my take on what each one means!!!!

LEEroy
MCNE6,CCNP,CWNA,CCSA,Project+

 

[Cluebird]

I agree with LEEroy for the answers and for the same reasons he states. A,C,D are the incorrect statements.

 

[mikeleahy]

what if you had to pick one