This week I’d like to get into a few details of how VLAN Trunking Protocol works. VTP is covered on the CCNA exams, and on the CCNP switching exam, and on the CCIE R/S written exam, to varying degrees. So, while everything I mention about VTP this week could matter for all these exams, I’m going to focus on examples that I think are most appropriate for the CCIE R/S written exam.
For the points I want to make about VTP, I need an example network and some example settings on a few switches. Since a lot of you have been participating with the sample questions over the last few weeks, I’ll start with a question, which gives me the example network that I need for the next few days, and gives you a sample question to enjoy.
You may want to time yourself, just for perspective, although I don’t expect to do any surveys about how long it takes to answer this question. But, if you like the perspective that gives you, start your timer… now!
Question: Switches Sw1, Sw2, Sw3, and Sw4 are not connected to each other or to any other switches. Each switch has the usual default VLANs configured (VLANs 1 and 1002-1005). Each switch also has one other VLAN configured, respectively: VLAN 11 on Sw1, VLAN 22 on Sw2, VLAN 33 on Sw3, and VLAN 44 on Sw4. The output of the show vtp status command on each switch is listed below; this output was gathered before the switches were connected. Then, Sw2 is connected to Sw1 using a trunk. Next, Sw3 is connected to Sw1 using a trunk. Finally, Sw4 is connected to Sw1 using a trunk. Which VLAN(s) are known by Sw1 at the end of this process, ie, which VLANs are in Sw1’s VLAN database at this point in time?
Answers:
A) 11
B) 22
C) 33
D) 44
Sw1# show vtp status
VTP Version : 2
Configuration Revision : 2
Maximum VLANs supported :1005
Number of existing VLANs : 6
VTP Operating Mode : Server
VTP Domain Name : CCIE-domain
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x0E 0x07 0x9D 0x9A 0x27 0x10 0x6C 0x0B
Sw2# show vtp status
VTP Version : 2
Configuration Revision : 4
Maximum VLANs supported : 1005
Number of existing VLANs : 6
VTP Operating Mode : Server
VTP Domain Name : CCIE-domain
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x0E 0x07 0x9D 0x9A 0x27 0x10 0x6C 0x0B
Sw3# show vtp status
VTP Version : 2
Configuration Revision : 6
Maximum VLANs supported : 1005
Number of existing VLANs : 6
VTP Operating Mode : Server
VTP Domain Name : CCIE-domain
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x07 0x0E 0x90 0xAA 0x27 0x10 0x6C 0x0B
Sw4# show vtp status
VTP Version : 2
Configuration Revision : 8
Maximum VLANs supported : 1005
Number of existing VLANs : 6
VTP Operating Mode : Client
VTP Domain Name : CCIE-domain
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x07 0x0E 0x90 0xAA 0x27 0x10 0x6C 0x0B
Tomorrow, I’ll list an answer, and get into a few details about VTP – but no hints for now.
