VTP mode setting on L3 switch

Answered Question
Dec 23rd, 2009

Hi frnds,

I am saravanan from Bangalore. In one of my customer has 4503 switch connected with 20 2950 switch. I want to enable the trunking protocol in between the both L3 and L2 switch dedicately. In 2950 Encapsulation dot1q and ISL options are not there, how can be to enable the trunking.

Then another issue, when i enable VTP mode from Transparen to server mode, how much time it will take. After enable the server mode, that L3 switch is hanging (there is no ping ), but when show vtp status and counters. It shows the number of advertisements and revision numbers also.

but it is hanging more than 2 minutes, so rollback in to old mode (transparent). Please tell me how much time it will take.

Thanks in advance

I have this problem too.
0 votes
Correct Answer by Ganesh Hariharan about 6 years 11 months ago

That great Saravanan that suggestions has helped you,It will be helpful if you can mark this thread  as answered and rate the post which has helped you.

Regards

Ganesh.H

Correct Answer by Peter Paluch about 6 years 11 months ago

Hello Saravanan,

Please try to go over the following steps:

  1. At the beginning, have all switches set to the VTP Transparent mode by issuing the command vtp mode transparent in the global configuration mode.
  2. On all switches, configure the VTP domain name using the vtp domain DOMAINNAME command in the global configuration mode, replacing the DOMAINNAME with your own domain name. The name is case sensitive and must be identical on all switches in the VTP domain.
  3. On all switches, set up the VTP password using the command vtp password MYPASSWORD in the global configuration mode, again replacing the MYPASSWORD with your own password. The password is also case sensitive and must be idendical on all switches in the VTP domain.
  4. On all switches, make sure that the VTP Pruning is deactivated and that the same VTP version is running by entering the following two commands: no vtp pruning and vtp version 1 in the global configuration mode.
  5. Make sure that all necessary VLANs exist on all switches by using the show vlan brief command and optionally creating missing VLANs as needed so that all switches know the necessary VLANs. Note that I want you to make the VLAN database consistent - do not rely on VTP as of yet. Switches should be still configured as VTP Transparent.
  6. Activate trunks between switches as suggested in my previous post and verify that the connectivity is maintained (leave up to 50 seconds for STP convergence). If you lose connectivity after you activate trunks, make sure that both the 4503 and the 2950 switch are configured for trunking on ports that interconnect these two switches, and also make sure that your PC is connected to an access port that is placed in a proper access VLAN to be able to reach the management address of the 4503 switch. Also make sure that the native VLAN on both switches is the same, preferably, leave it unmodified (i.e. VLAN1).
  7. After the trunks are set up in such a way that the connectivity is working, configure the 4503 switch as VTP Server using the vtp mode server global configuration command, and all other switches as VTP Clients using the vtp mode client global configuration command. Verify again that the connectivity has not been interrupted.
  8. Create an experimental VLAN on the 4503 switch (say 999) and exit the configuration mode. Make sure afterwards that the VLAN has also been added to other switches in your VTP domain.

I suppose that this sequence of steps can help you to deploy the VTP successfully in your network but please be careful to follow the individual steps very closely and if there are any unclear or unexpected things, please come back and ask again.

Best regards,

Peter

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Peter Paluch Wed, 12/23/2009 - 04:04

Hello Saravanan,

On 2950 switches, the only supported trunking protocol is the IEEE 802.1Q. Therefore, the only command necessary to activate trunking on a port of the 2950 switch is:

interface FastEthernet 0/1

switchport mode trunk

The corresponding port on the 4503 switch should be configured with:

interface FastEthernet 0/1

switchport trunk encapsulation dot1q

switchport mode trunk

Regarding the VTP protocol, I am not quite sure what you are asking about. A change from VTP Transparent to Server mode takes place immediately after you change the mode (and if you are using the VLAN database mode instead of usual global configuration, you need to issue the exit command for changes to take effect). However, the VTP propagates only through trunk links - its datagrams are not sent on access ports or on routed ports. Also, each switch has to be converted from VTP Transparent to VTP Server/Client mode individually - this setting will not propagate through VTP.

Perhaps you have the VTP Pruning activated. If the VTP Pruning is activated but the neighboring switches have not joined your VTP domain successfully (they are VTP Transparent, or their VTP domain name is different, the VTP password is mismatched, the trunking is not working properly between the 4503 and the neighboring switches), the VLANs will be pruned off the existing trunks, thereby possibly leading to the SVI interfaces going down. Try deactivating the VTP Pruning.

In any case, deploying a VTP in a customer's network needs more planning than just turning it on. I recommend caution and more testing before rolling out.

Best regards,

Peter

psaravanan Wed, 12/23/2009 - 04:16

Thanks mr. peter paluch,

I will the neighbor switch vtp status, domain and mode also.

actually

4503  ------>  2950---->  i am in here,

I changed the mode from VTP transparent to vtp server in 4503, then communication is dropped in my place, respectively all other switches (L2) which are connected to 4503 also not communicated. That is the issue.

Next thing is, After enable the trunk mode in both side, cisco 2950 is not accept the other vlan   except the switch vlan. I enable Trunk allowed vlan all

also. even though the same thing is going on.

So what is the problem is that issue.

Correct Answer
Peter Paluch Wed, 12/23/2009 - 13:12

Hello Saravanan,

Please try to go over the following steps:

  1. At the beginning, have all switches set to the VTP Transparent mode by issuing the command vtp mode transparent in the global configuration mode.
  2. On all switches, configure the VTP domain name using the vtp domain DOMAINNAME command in the global configuration mode, replacing the DOMAINNAME with your own domain name. The name is case sensitive and must be identical on all switches in the VTP domain.
  3. On all switches, set up the VTP password using the command vtp password MYPASSWORD in the global configuration mode, again replacing the MYPASSWORD with your own password. The password is also case sensitive and must be idendical on all switches in the VTP domain.
  4. On all switches, make sure that the VTP Pruning is deactivated and that the same VTP version is running by entering the following two commands: no vtp pruning and vtp version 1 in the global configuration mode.
  5. Make sure that all necessary VLANs exist on all switches by using the show vlan brief command and optionally creating missing VLANs as needed so that all switches know the necessary VLANs. Note that I want you to make the VLAN database consistent - do not rely on VTP as of yet. Switches should be still configured as VTP Transparent.
  6. Activate trunks between switches as suggested in my previous post and verify that the connectivity is maintained (leave up to 50 seconds for STP convergence). If you lose connectivity after you activate trunks, make sure that both the 4503 and the 2950 switch are configured for trunking on ports that interconnect these two switches, and also make sure that your PC is connected to an access port that is placed in a proper access VLAN to be able to reach the management address of the 4503 switch. Also make sure that the native VLAN on both switches is the same, preferably, leave it unmodified (i.e. VLAN1).
  7. After the trunks are set up in such a way that the connectivity is working, configure the 4503 switch as VTP Server using the vtp mode server global configuration command, and all other switches as VTP Clients using the vtp mode client global configuration command. Verify again that the connectivity has not been interrupted.
  8. Create an experimental VLAN on the 4503 switch (say 999) and exit the configuration mode. Make sure afterwards that the VLAN has also been added to other switches in your VTP domain.

I suppose that this sequence of steps can help you to deploy the VTP successfully in your network but please be careful to follow the individual steps very closely and if there are any unclear or unexpected things, please come back and ask again.

Best regards,

Peter

psaravanan Thu, 12/24/2009 - 01:01

Very very thanks sir,

i will follow the procedure to do the vtp process, when i have downtime of the switch.

psaravanan Fri, 12/25/2009 - 01:10

Dear mr. peter,

In catalayst 500 series switches, vtp modes are not there, i have a doubt about the vtp modes.

Is it allow the vtp modes automatically or is it not available.

please tell ya.

Ganesh Hariharan Fri, 12/25/2009 - 01:30

Hi ,

In Cat OS you need to try with set commands,check out the below commands in cat 500 series switch hope this helps out your query !!

set vtp domain domain-name

set vtp mode transparent
set vtp mode off

Regards

Ganesh.H

psaravanan Fri, 12/25/2009 - 02:11

Mr. Ganesh Sir,

In Catalyst 500 series switches dont have telnet option, only web browsing only available.

In the web browsing VTP Option is not there. So it will pass the vtp status or not.

CLI mode is not there in c500 switches.

Peter Paluch Fri, 12/25/2009 - 03:51

Hi Ganesh,

Thanks for insight how to configure VTP setting on CatOS-based switch but Saravanan was asking about Express 500 series switches, not about Catalyst 5000.

Best regards,

Peter

Peter Paluch Fri, 12/25/2009 - 03:51

Hello Saravanan,

On Cisco Catalyst Express 500 Series switches, there is currently no support for VTP protocol. As a matter of of fact, these switches relay the VTP messages transparently, thereby behaving as VTP Transparent switches. You may visit the following URL for additional information:

http://www.cisco.com/en/US/tech/tk389/tk689/technologies_configuration_example09186a0080890607.shtml#conf4

On Catalyst Express 500 Series switches, you will have to create all necessary VLANs manually.

Best regards,

Peter

psaravanan Sat, 12/26/2009 - 00:02

Thanks Mr. Ganesh & Peter,

I want to send logging information to syslog server, how can i enable in Express 500 series,

Please suggest any syslog server for freeware and full. Currently i am using Kiwi syslog server free version.

Peter Paluch Sat, 12/26/2009 - 00:57

Hello Saravanan,

Your question regarding the Syslog server is no longer pertaining to the original thread topic (the VTP protocol). In future, please, create a new thread so that other people looking for similar issue can find it easily.

Regarding the Syslog server implementation, I personally recommend running Linux and using the syslog-ng. It is very capable and it allows you to sort your logging messages according to various criteria into logfiles. I haven't been using any Windows version of Syslog software and frankly, I do not know any. Luckily, I never needed it

Best regards,

Peter

psaravanan Sat, 12/26/2009 - 06:35

Thanks Mr. Ganesh & Mr.Peter,

Shall we close the discussion, Thanks for sharing Information.

Correct Answer
Ganesh Hariharan Sat, 12/26/2009 - 06:44

That great Saravanan that suggestions has helped you,It will be helpful if you can mark this thread  as answered and rate the post which has helped you.

Regards

Ganesh.H

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