VTP Questions 3
Question 1
Explanation
During switch boot up, the switch compares the content in the vlan.dat file and the configuration in startup-config to determine if it should use the configuration in vlan.dat or startup-config. When you save VTP mode, domain name, and VLAN configurations in the switch startup configuration file and reboot the switch, the VTP and VLAN configurations are selected by these conditions:
+ If both the VLAN database and the configuration file show the VTP mode as transparent and the VTP domain names match, the VLAN database is ignored. The VTP and VLAN configurations in the startup configuration file are used. The VLAN database revision number remains unchanged in the VLAN database.
+ If the startup VTP mode is server mode, or the startup VTP mode or domain names do not match the VLAN database, VTP mode and VLAN configuration for the first 1005 VLANs are selected by VLAN database information, such as the vlan.dat file. VLANs greater than 1005 are configured from the switch configuration file (startup-config file).
Question 2
Question 3
Question 4
Explanation
VTP pruning should only be enabled on VTP servers, all the clients in the VTP domain will automatically enable VTP pruning -> C is correct.
Question 5
Explanation
In fact this is an unclear question. VLAN 1 (and VLANs 1002 to 1005) are always pruning-ineligible (even when VLAN 1 is not the native VLAN) so answers C D are not correct.
But answers A and B are not correct too as VLANs 2 through 9 are pruned (at least on SW1).
Maybe the author of this question forgot that VLAN 1 is pruning-ineligible. If so the best choice should be C.
Question 6
Explanation
In addition to propagating VTP information, version 3 can propagate Multiple Spanning Tree (MST) protocol database information. A separate instance of the VTP protocol runs for each application that uses VTP -> Only VTPv3 supports multiple VTP instances -> Answer A is not correct.
VTP version 1 and version 2 support only normal-range VLANs (VLAN IDs 1 to 1005). VTP version 3 supports the entire VLAN range (VLANs 1 to 4094). Extended range VLANs (VLANs 1006 to 4094) are supported only in VTP version 3. You cannot convert from VTP version 3 to VTP version 2 if extended VLANs are configured in the domain.
Only VTPv3 allows to turn on/off per-port basis -> Answers C, E are not correct.
Consistency Checks: In VTP version 2, VLAN consistency checks (such as VLAN names and values) are performed only when you enter new information through the CLI or SNMP. Consistency checks are not performed when new information is obtained from a VTP message or when information is read from NVRAM. Therefore answer D is not correct.
Question 7
Explanation
In VTP versions 1 and 2, the switch must be in VTP transparent mode when you create extended-range VLANs. VTP version 3 also supports creating extended-range VLANs in client or server mode -> Answer A is correct.
Extended-range VLANs range from 1006-4094, inclusive. However, if using VTPv1 or VTPv2, these additional VLANs cannot be configured in VLAN database mode, nor stored in the vlan.dat file, nor advertised through VTP (so answer E is not correct). In fact, to configure them, the switch must be in VTP transparent mode. VTPv3 removes these limitations: Both normal- and extended-range VLANs can be advertised by VTPv3. Also, with VTPv3, information about all VLANs is again stored in the vlan.dat file in Flash -> Therefore VTPv3 stores the extended-range VLAN in VLAN database (vlan.dat file).
Reference: CCIE Routing and Switching v5.0 Official Cert Guide, Volume 1, Fifth Edition
VLAN 1 and VLANs 1002 to 1005 are always pruning-ineligible; traffic from these VLANs cannot be pruned. Extended-range VLANs (VLAN IDs greater than 1005) are also pruning-ineligible -> Answer D is correct.
Reference: https://www.cisco.com/c/en/us/support/docs/lan-switching/vtp/10558-21.html
Question 8
Explanation
VTP version 3 supports creating extended-range VLANs in client or server mode -> Answer B and D are not correct.
Private VLANs can only be configured when VTP is in transparent/off modes in VTP version 1 or 2 and in server/transparent/off modes in VTP version 3 when pruning is turned off -> Answer A is correct while answer E is not correct.
Question 9
Explanation
VTP version 3 supports creating extended-range VLANs in client or server mode -> Answer B and D are not correct.
Private VLANs can only be configured when VTP is in transparent/off modes in VTP version 1 or 2 and in server/transparent/off modes in VTP version 3 when pruning is turned off -> Answer A is correct while answer E is not correct.
Question 10
Explanation
Much work has gone into improving the usability of VTP version 3 in three major areas:
+ The new version of VTP offers better administrative control over which device is allowed to update other devices’ view of the VLAN topology. The chance of unintended and disruptive changes is significantly reduced, and availability is increased. The reduced risk of unintended changes will ease the change process and help speed deployment.
+ Functionality for the VLAN environment has been significantly expanded. Two enhancements are most beneficial for today’s networks:
– In addition to supporting the earlier ISL VLAN range from 1 to 1001, the new version supports the whole IEEE 802.1Q VLAN range up to 4095.
– In addition to supporting the concept of normal VLANs, VTP version 3 can transfer information regarding Private VLAN (PVLAN) structures.
+ The third area of major improvement is support for databases other than VLAN (for example, MST).
This is why I HATE cisco tests along with all the other certification garbage.
If the startup VTP mode is server mode, or the startup VTP mode or domain names do not match the VLAN database, VTP mode and VLAN configuration for the first 1005 VLANs are selected by VLAN database information, such as the vlan.dat file. VLANs greater than 1005 are configured from the switch configuration file.
That is from the 2900 series switch yet the 3650 NEVER once mentions vlans > 1005 are configured from the switch config file. It states that IF YOU create them and then it talks about the conditions
Cisco documentation is all over the place and 3 different books will have 3 different answers and sometimes all 3 books will have NO answers to the question.
@Anonymous
Which two statements about VTP modes are true? (Choose two)
A. Private VLANs are supported on devices that run VTP version 2 in transparent mode
B. Extended VLANs are supported only on devices that run VTP version 3 in server mode
C. When VTP pruning is enabled on a VTP server, it is enabled for the entire management domain
D. Extended VLANs are supported only on devices that run VTP version 3 in client mode
E. Private VLANs are supported on devices that run any version of VTP in server mode
B cannot be correct as a whole. Here is the statement:
In VTP versions 1 and 2, the switch must be in VTP transparent mode when you create extended-range VLANs. VTP version 3 also supports creating extended-range VLANs in client or server mode. See the “Configuring Extended-Range VLANs”
Answer B says “supported ONLY on devices that run vtpv 3 in server mode”, not true. Extended vlans are supported in BOTH server and client mode for vtp3. So if B is correct then D is correct as well.
Now for private-vlan
In VTP versions 1 and 2, the switch must be in VTP transparent mode when you create private VLANs and when they are configured, you should not change the VTP mode from transparent to client or server mode. VTP version 3 also supports private VLANs in client and server modes. See Chapter 16, “Configuring Private VLANs.”
When the switch is in VTP transparent mode, the VTP and VLAN configurations are saved in NVRAM, but they are not advertised to other switches
This makes A as correct as possible. AC is the answer. BC cannot be the answer without also include D.
This is 3560 switch configuration.
Q5:
Hello All, some more comments on Q5. my previous comments might not be accurate.
if the author meant VLAN 2 rather than VLAN 1, then B & C will be correct. VLAN 2 to 101 are operational on all switches. And VLAN 2 to 9 are pruned on sw1 & sw4. Pruning means blocking/not sending broadcast messages to a switch if there are no ports on that switch which are members of that VLAN (which is sending brd). But in the meantime these VLANs are still fully operational on the trunk links and on the destination switch. Also by default, all VLANs are permitted on trunk ports (with no configs are required such as switchport trunk allowed VLAN xxx). And both A & D are not correct.
But if the author really means VLAN 1. Then:
A: is not correct because 2 to 9 are (can be) pruned between SW1, SW2, SW3 & SW4. (see output below from my switch: vtp v3, client mode, pruning enabled). So I think the SWs will prune VLAN 2 through 9.
B: is correct because VLAN 1 through 101 are operational on all switches. Pruning stops only brd traffic, but the VLANs are still operational if (when) a switch port is assigned to one of these VLANs on one of the switches.
C: can’t be correct as VLAN 1 can’t be pruned by vtp.
D: as in C, VLAN 1 can’t be pruned by vtp.
Ok, let me now make it even more complex :-) that was with regards to vtp pruning. But maybe the author didn’t exclude in his mind manual pruning on trunk links (C3750-1(config-if)# switchport trunk allowed vlan xxx). We always manually prune VLAN 1 for security reasons, never use it so we do not permit/allow it on a trunk port.
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C3750G-3(config)#do sh vtp status
VTP Version capable : 1 to 3
VTP version running : 3
VTP Domain Name : moayad.net
VTP Pruning Mode : Enabled
VTP Traps Generation : Disabled
Device ID : 001f.9e05.0080
Feature VLAN:
————–
VTP Operating Mode : Client
Number of existing VLANs : 14
Number of existing extended VLANs : 0
Configuration Revision : 0
Primary ID : 0000.0000.0000
Primary Description :
MD5 digest : 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
Feature MST:
————–
VTP Operating Mode : Transparent
Feature UNKNOWN:
————–
VTP Operating Mode : Transparent
C3750G-3(config)#
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