Voice Support Questions
Here you will find answers to Voice Support Questions
(Questions 1 to 4 use the same picture)
Question 1:
You work as a network technician, study the exhibit carefully. What is the effect on the trust boundary of configuring the command mls qos trust cos on the switch port that is connected to the IP phone?

A – Effectively the trust boundary has been moved to the IP phone.
B – The host is now establishing the CoS value and has effectively become the trust boundary.
C – The switch SW is rewriting packets it receives from the IP phone and determining the CoS value.
D – The switch SW will no longer tag incoming voice packets and will trust the distribution layer switch to set the CoS.
Answer: A
Explanation:
The “mls qos trust cos” command is used to configure the port trust state (by default, the port is not trusted). By using this command, you can configure the switch port to which the telephone is connected to trust the CoS labels of all traffic received on that port.
(Note: All current Cisco IP Phones include an internal three-port Layer 2 switch therefore you can think an IP Phone as a switch and network administrators generally accept a Cisco IP Phone as a trusted device.)
Question 2:
If you are a network technician, study the exhibit carefully. Which switch interface configuration command would automatically configure quality of service (QoS) for voice over IP (VoIP) within a QoS domain?
A. auto qos voip cisco-phone
B. mls qos trust
C. switchport priority extend cos 7
D. switchport priority extend trust
Answer: A
Explanation:
The command “mls qos trust” is used to configure the port trust state (by default, the port is not trusted).
The command “switchport priority extend cos 7″ sets the IP phone port to override the priority received from the PC or the attached device (7 is the highest priority).
The command “switchport priority extend trust” tells the Cisco IP Phone to trust the CoS value of the connected PC without remark all packets sent form PC to CoS 0, by default.
Question 3:
Study the exhibit carefully. Which statement is true about the voice traffic coming to the switch access port that is connected to the IP phone?
A. The voice VLAN must be configured as a native VLAN on the switch.
B. A PC connected to a switch port via an IP phone must support a trunking encapsulation.
C. The traffic on the voice VLAN must be tagged with 802.1p encapsulation in order to coexist on the same LAN segment with a PC.
D. A PC connected to a switch port via an IP phone is unaware of the presence of the phone.
Answer: D
Explanation:
The voice VLAN can be configured over a unique voice VLAN (known as the voice VLAN ID or VVID) or over native VLAN -> A is not correct.
The ports k between PC and IP Phone are always functioned as access-mode switch ports so there is no need to support a trunking encapsulation -> B is not correct.
The traffic on the voice VLAN can be tagged with 802.1p encapsulation or 802.1q encapsulation -> C is not correct.
Most Cisco IP Phone models operate as a three-port switch as shown below. Nowadays, the voice traffic and data traffic will normally be on different IP subnets and the IP Phone is unaware of the presence of the phone.

Question 4:
Study the exhibit carefully. Which statement is true when voice traffic is forwarded on the same VLAN used by the data traffic?
A. Quality of service cannot be applied for the voice traffic.
B. The voice traffic cannot be forwarded to the distribution layer.
C. Port security cannot be enabled on the switch that is attached to the IP phone.
D. The voice traffic cannot use 802.1p priority tagging.
Answer: D
Question 5:
Which two codes are supported by Cisco VoIP equipment?
A. G.701 and G719
B. G.711 and G.729
C. G.721 and G.739
D. G.731 and G.749
Answer: B
Question 6:
Study the exhibit carefully, then tell me what is the problem with this configuration?

A – Spanning tree PortFast cannot be configured on a port where a voice VLAN is configured.
B – The switch port must be configured as a trunk.
C – Sticky secure MAC addresses cannot be used on a port when a voice VLAN is configured.
D – Spanning tree PortFast cannot be configured on a port when a sticky secure MAC address is used.
Answer: C

Study the exhibit carefully. Which statement is true about a voice VLAN
segment?
A. Physically the voice network and the data network are separate.
B. The voice traffic will normally be on a different IP subnet than will th
C. End user intervention is necessary to place the phone into the prop
D. The same security policy should be implemented for both voice and data traffic.
E. The data VLAN resides in the native VLAN. F. None of the other alternatives apply
ti 3.3 say right answer is B
passguife 3.21 says right answer is E
Wat is right answer?
@akaEvgen
I prefer B, voice vlan usually use a different ip address space besides the host.
talking about E, usually there is no “native vlan” in a voice access port, because native vlan is usually refered in trunk port.
@bypasser
Thanks.
From official certification guide page 310
Right answer is E. Because data reside in access vlan when “switchport voice vlan none”
All other situation the data vlan is a native vlan
This question is a bit misleading, in that there are multiple things wrong with the config as per the diagram. I guess that if one can ignore all the other stuff then answer would be C.
Cisco Website on 3560
http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_25_se/configuration/guide/swtrafc.html
You cannot configure static secure or sticky secure MAC addresses in the voice VLAN.
——————————————————————————–
Note Voice VLAN is only supported on access ports and not on trunk ports, even though the configuration is allowed.
Study the exhibit carefully. Which statement is true about a voice VLAN
segment?
A. Physically the voice network and the data network are separate.
B. The voice traffic will normally be on a different IP subnet than will th
C. End user intervention is necessary to place the phone into the prop
D. The same security policy should be implemented for both voice and data traffic.
E. The data VLAN resides in the native VLAN.
F. None of the other alternatives apply
Has to be E–the voice vlan is the tagged vlan, data is the untagged vlan. Can’t place voice and data with a sticky-mac so that’s that as they say…
Q4: I think the answer should be corrected as:
D. The voice traffic CAN use 802.1p priority tagging.
it is written as “can not” above, but it can use 802.1P priority tagging to give voice traffic a
higher priority and forward all voice traffic through the native (access) VLAN.
Obviously i cant see the config but.
on a port you will likely do 2 commands:
switchport access vlan 10 (for example)
switchport voice vlan 20.
this means data traffic is in vlan 10, and will be tagged, so it will nto be on the native vlan (which shoudl be pruned off the trunk anyway)
So, id go with B.
Also, onl the basis that a different vlan has a different subnet assigned to it. as voice will require separate CoS, it will have a separate vlan. So yes. B.
Thank you for another great article. Where else could anyone get that kind of information in such a perfect way of writing? I have a presentation next week, and I am on the look for such information.
@akaEvgen
I actually like answer E for that question. While I can’t see the exhibit, if it is configured with:
switchport access vlan 10
switchport voice vlan 20
The voice traffic resides in the auxiliary vlan 20 and the data traffic resides in the native vlan 10.
QUESTION
VoIP—-How does the switch carry vlan information for the IP phone when the interface connecting the phone has been hardcoded as an access port???
I’ve recently started a blog, the information you provide on this site has helped me tremendously. Thank you for all of your time & work.
Q3. I couldn’t understant why answer 3 is ok . I found out on cisco wbe that when “switchport port-security mac-address sticky” is configured on voip port “the maximum number of allowable MAC addresses on this port should be changed to three”.
Configure IOS Catalyst Switches to Connect Cisco IP Phones Configuration Example
http://www.cisco.com/en/US/products/hw/switches/ps4324/products_configuration_example09186a0080722cdb.shtml
..The Cisco7960 IP phone contains an integrated three-port 10 100 switch. ..Because a Cisco7960 IP phone also supports connection to a PC or another device an interface connecting a Catalyst4500 series switch to a Cisco7960 IP phone can carry a mix of voice and data traffic.
I find myself coming to your blog more and more often to the point where my visits are almost daily now!
Can anyone say me if the answeres of exam are the same that are posted here?
You certainly have some agreeable opinions and views. Your blog provides a fresh look at the subject.
I like the pictures of the IP phone’s being used in these diagrams, very realistic!
I am not sure about the last question!! Is that valid only with Cisco IP phones, cause I find it strange.
we use sticky on all our switchports and all are configured with vlan voice.
However , we use Avaya , not Cisco phones.
@Seattle
There are different modes of Voice and Data VLAN access ports (802.1q, etc) , some of them place voice in VLAN 0, some place data in native VLAN, others in access VLAN. So E cannot be the right option.
Regards,
Sarah G
I’ve been visiting your blog for a while now and I always find a gem in your new posts. Thanks for sharing.
I just book marked your blog on Digg and StumbleUpon.I enjoy reading your commentaries.
Que pensamiento simpГЎtico
Really great article with very interesting information. You might want to follow up to this topic!?! 2012
Really interesting blog, keep up the good work!
Thanks for tris interesting information! I found it very useful =)
Hi guys
I`ll make my exam next week, i want to know how much(generally) of question about wireless and voice appers on the exam ?
Already talked to some people and I was told not appear more than two questions from each topic, this is true?
Thank you
Choose two. The network administrator will be able to configure VLANs of local significance on this switch. VLANs can only be added to the VLAN database on this switch by a VTP advertisement. All VLANs that are configured on this switch will be sent to all other switches in the same VTP domain.
HShTOh Left on my site a link to this post. I think many people will be interested in it..!
dhoSwr Yeah, now it’s clear !… And firstly I did not understand very much where there was the link with the title itself !!….
lEBAlZ Yeah, in my opinion, it is written on every fence!!….
please help me with the latest dumps, cant afford to buy it.. am writing my exam very soon. God bless.. my email is jideedu@gmail.com
Question Number 6 – SHENANIGANS! I successfully implemented port security using mac-address sticky command with a voice vlan on the port. See below.. Cisco 3750!
interface FastEthernet2/0/24
switchport mode access
switchport voice vlan 210
switchport port-security maximum 2
switchport port-security
switchport port-security mac-address sticky
switchport port-security mac-address sticky 0021.9b6b.1449
switchport port-security mac-address sticky 3cb1.5b11.2c54 vlan voice
spanning-tree portfast
end
hi on 21st i gave exam i passed it with 934 score.
hey guys earlier i was nervous but when u saw the 1st q in my exam, i smiled.
qs were easy dont need to hesitate.
i had finished my exam within 1 Hr.
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ALL tHE Best to all PEOPLE FOR Christmas & 2012.
Can someone please explain the answer of Q6. I am gonna appear for SWITCH in 3 days!! Please!!
I have a doubt about question #1. According to you, the command “mls qos trust cos” will move the trust boundary to the IP phone. However, what that command really does is move the trust boundary to the distribution switch because it’ll trust COS from both the phone and the computer. I believe the correct command for answer A is “mls qos trust device cisco-phone”, because it’ll trust COS from only the phone and tell the phone to mark the COS from the computer as 1.
Sorry I was wrong. I did a little more research and found that “mls qos trust cos” will trust COS coming only from the tagged packets, which is obviously the voice vlan, and the untagged data packets will not have a COS value. The command “mls qos trust device cisco-phone” is actually a macro that will put the following commands in if it detects an ip phone via CDP:
-mls qos trust dscp
-mls qos trust ip-precedence
-mls qos trust cos interface command.
Thanks inspiring me to look more into it.
D73CB8 comment6
Hi,
Any one could tell me which one is latest Dumps.
i have to plann to write a exam on 11th Feb.
hi guys i just want to confirm that how many questions we have in actual test or in exam collection for ccnp switching
http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_19_ea1/configuration/guide/swvoip.html
Voice VLAN Configuration Guidelines
These are the voice VLAN configuration guidelines:
•You should configure voice VLAN on switch access ports.
•Before you enable voice VLAN, we recommend that you enable QoS on the switch by entering the mls qos global configuration command and configure the port trust state to trust by entering the mls qos trust cos interface configuration command.
•The Port Fast feature is automatically enabled when voice VLAN is configured. When you disable voice VLAN, the Port Fast feature is not automatically disabled.
•When you enable port security on an interface that is also configured with a voice VLAN, you must set the maximum allowed secure addresses on the port to at least two.
•If any type of port security is enabled on the access VLAN, dynamic port security is automatically enabled on the voice VLAN.
•You cannot configure static secure or sticky secure MAC addresses on a voice VLAN.
•Voice VLAN ports can also be these port types:
–Dynamic access port. See the “Configuring Dynamic Access Ports on VMPS Clients” section for more information.
–Secure port. See the “Configuring Port Security” section for more information.
–802.1X authenticated port. See the “Using 802.1X with Voice VLAN Ports” section for more information.
–Protected port. See the “Configuring Protected Ports” section for more information.
With newer IOS releases like 15.0.1SE You can now configure static secure or sticky secure MAC addresses on a voice VLAN.
Refer:
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/15.0_1_se/configuration/guide/swtrafc.html#wp1038546
Above Link should actualy be:
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/15.0_1_se/configuration/guide/swvoip.html
Really informative post.Much thanks again. Will read on…
1agMfm Really appreciate you sharing this article post. Great.
Hi
Thank you for helping networking topics to be at the reach of everybody, what helps improve the real life experience of our comunity, you are a gentleman
What does the interface subcommand switchport voice vlan 222 indicate?
A. The port is configured for both data and voice traffic.
B. The port is fully dedicated to forwarding voice traffic.
C. The port will operate as an FXS telephony port.
D. Voice traffic will be redirected to VLAN 222.
Answer: A
is that correct coz i think D is correct ?
Hey Guys. I have done my Switching exam and got 846/1000.
Labs were still LACP with STP, MLS with EIGRP, AAAdot1x.
Also the nonentity dumps are still valid.
I request all the members to share the experience here so that others will be benefited. Help other to get certified.
Few things to remember.
————————————–
Switch locations are different and names are different in exam
I got only 2 wireless questions & 3 questions on IP telephony
Total 40 questions including 4 LABS
ALl LABs are from above website. Do it carefully
HSRP hot spot comes with 6 questions. Do it carefully.
Dumps are still valid & here is the name of the file – Cisco.ActualTest.642-813.v2011-11-11.by.nonentity.407q.vce
Make sure you are good in HSRP,Spanning Tree, IP telephony, Ether channel (PagP/LACP), making root bridge for Vlans
Few things added in LACP with STP sim. They will ask you to keep VTP mode same as Switch A. Spanning tree version same as Switch B. Keep a eye on expectations of questions and make sure you verify before move on.
In Etherchannel sim they will ask you to use non-proprietary encapsulation so use dot1.q for encapsulation between ether channels. One more thing to remember that the ether channel ports fa0/3 and fa0/4 are in different vlan (Vlan98) so remove those from VLAN 98 by command under interface range f0/3 – 4 , no spanning-tree vlan 98
I have lot more to share but don’t remember until some one ask for it. So post here if you need anything from Me, I will be happy to help
Rock on guys.
We are running IOS 12.4 in our environment
We have voice vlan and data vlan configured on our access switches.
We use dot1x mostly, but there are some areas where we are using port-security mac-address sticky
Guess what? Voice and Data mac addresses become “stuck” to the port.
So, why does the question indicate that you cannot use sticky-secure ???
Appreciate you sharing, great article. Cool.
hen you enable port security on interface that is also configruaed with voice vlan . what is the maximum number of secure mac address ?
1-no more than one mac
2-the default will be set
3-the ip phone should use a dedicated port , therefore only one mac address is need per port
4-no value is needed if the switchport priority command is configured
5-no more than two secure mac addressess should be set
which one is correct .
@ahmed
I have seen two different answers to that question, both 2 and 5, so I have the same question as you!
answer to that question (5):
http://www.cisco.com/en/US/docs/switches/lan/catalyst2950/software/release/12.1_14_ea1/configuration/guide/swvoip.html
To anyone who has recently sat the exam, are there many VOIP questions on the exam?
Hi Guys,
Seeing the answer right in front your eyes before making selection is annoying. So i grabs all of the questions on this site and put them into VCE file to make my life easier. Be sure to check back CertPrepare site regularly for updates.
Here is the file: http://www.4shared.com/file/C5hmKPbb/CCNP_642-813_CertPrepare-by_Hu.html
Best of luck !!!
Can anyone really confirm this?!!!!
hen you enable port security on interface that is also configruaed with voice vlan . what is the maximum number of secure mac address ?
1-no more than one mac
2-the default will be set
3-the ip phone should use a dedicated port , therefore only one mac address is need per port
4-no value is needed if the switchport priority command is configured
5-no more than two secure mac addressess should be set
which one is correct .
nEJYpo Great blog.Really thank you! Cool.
These answers are a bit fluffy
Trescool is the option 2
Trescool is the option 2
@Q4
why answer A is uncorrect ?
Um, well because quality of service can be applied to voice traffic. In fact, I don’t think anybody would use VOIP if A were correct.
Nothing from this section was in test today.
Hi All,
VOIP is still on ccnp switch exam?
Thank you!