Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Management domain length in VTP

Hi,

I'm preparing for my CCNA. Please don't mind if this is too small question to ask here.

What does the Management Domain length contains in a VTP packet?

Here is the screenshot from a cisco doc for understanding VTP.

management domain length.PNG

Regards,

Chandu              

Regards, Chandu
Everyone's tags (1)
1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Management domain length in VTP

Chandu,

1. Can we find out how many switches are there in the vtp domain including server, client & tansp?

There is no automatic tool for this. VTP protocol itself has no provisions to enumerate the count of switches in a VTP domain and their roles.

2. How to find the count of client switches & transp switches?

Not possible with VTP tools. You could of course visit the configuration of each switch and check its VTP settings but this option is probably not what you are asking for.

And finally is there any use to include the length of the domain name?

Because the IOS needs to know how many bytes in the "Management domain name" field are significant. If you were writing a software to process VTP packets, you would be able to read the entire "Management domain name" field as a 32-byte long string into memory easily, but you still need to know how long is the VTP domain name in that string.

Best regards,

Peter

5 REPLIES
Cisco Employee

Management domain length in VTP

Hi Chandu,

The "Management domain length" is an unfortunate field designation. In reality, this field says what is the length of the VTP domain name.

In VTP packet header, the field for VTP domain name - the "Management domain name" has a constant length of 32 bytes. However, the true length of the VTP domain name can be anywhere between 1 and 32 characters, so the packet also carries information about how long the name is, exactly in the "Management domain length" field. If your VTP domain name is, say, "CCNA" then only 4 bytes out of 32 are occupied in the domain name field, and the "Management domain length" would carry the value of 4.

Best regards,

Peter

VIP Purple

Management domain length in VTP

HI Chandu,

Management domain Length: Used to specify the length of the VTP management domain or Indicates the size of the name that follows

The main purpose of VTP is to provide a facility by which individual Cisco switches can be managed as a group for VLAN configuration purposes. A VTP management domain is simply a group of switches that participate in sharing VTP information. A given switch can be part of only one VTP management domain at a time, and is part of no VTP management domain by default.

Regards

Dont forget to rate helpful posts.

New Member

Management domain length in VTP

Thanks to you both.

I've two more questions:

1. Can we find out how many switches are there in the vtp domain including server, client & tansp?

2. How to find the count of client switches & transp switches?

Is there any way?

Thanks in advance.

Regards,

Chandu

Regards, Chandu
New Member

Management domain length in VTP

And finally is there any use to include the length of the domain name?

Regards,

Chnadu

Regards, Chandu
Cisco Employee

Management domain length in VTP

Chandu,

1. Can we find out how many switches are there in the vtp domain including server, client & tansp?

There is no automatic tool for this. VTP protocol itself has no provisions to enumerate the count of switches in a VTP domain and their roles.

2. How to find the count of client switches & transp switches?

Not possible with VTP tools. You could of course visit the configuration of each switch and check its VTP settings but this option is probably not what you are asking for.

And finally is there any use to include the length of the domain name?

Because the IOS needs to know how many bytes in the "Management domain name" field are significant. If you were writing a software to process VTP packets, you would be able to read the entire "Management domain name" field as a 32-byte long string into memory easily, but you still need to know how long is the VTP domain name in that string.

Best regards,

Peter

211
Views
8
Helpful
5
Replies