Skip to main content

Why Extended-Range VLANs are not supported or transported by VTP Ver 1 and 2?

Normal-Range and Extended-Range VLANs Normal-range VLANs are VLANs 1–1005, and can be advertised via VTP versions 1 and 2. These VLANs can be configured in VLAN database mode, with the details being stored in the vlan.dat file in Flash.

Extended-range VLANs range from 1006–4094, inclusive. However, these additional VLANs cannot be configured in VLAN database mode, nor stored in the vlan.dat file, nor advertised via VTP. They can only be configured when the switch is in VTP transparent mode.

Now answering the question that why Extended range VLANs are not transported by VTP 1
& 2, is because originally, ISL began life only supporting normal-range VLANs, using only 10
of the 15 bits reserved in the ISL header to identify the VLAN ID.
These 10 bits makes the combinations of only 1024 Vlans, thus supporting only 1024 Normal Range-VLANs.

The later-defined 802.1Q used a 12-bit VLAN ID field, thereby allowing support of the extended range. Following that, Cisco changed ISL to use 12 of its reserved 15 bits in the VLAN ID field, thereby supporting the extended range.

Both ISL and 802.1Q support extended-range VLANs today with VTP version 3.0

Storing VLAN Configuration VTP Ver 1 & 2 
Catalyst IOS stores VLAN and VTP configuration in one of two places—either in a Flash file called vlan.dat or in the running configuration. IOS chooses the storage location in part based on the VTP mode, and in part based on whether the VLANs are normal range VLANs or extended-range VLANs.
Table below, describes what happens based on what configuration mode is used to configure the VLANs, the VTP mode, and the VLAN range. (Note that VTP clients also store the VLAN configuration in vlan.dat, and they do not understand extended range VLANs.) 


Storing VLAN Configuration VTP Ver 3.0
VTP3 expands and enhances the concept of the server role. The default server role will be the secondary server subtype. In addition, only one server per domain can be prompted to be a primary server. Client and secondary server devices receive a configuration from a primary server.
A secondary server stores the received configuration in a local permanent storage space (for example, NVRAM) and updates other devices in the same domain and for the same instance.

Comments

Popular posts from this blog

Connection control operation failed for disk 'ide1:0'

I was getting this error while removing Operating System ISO image mounted on the Virtual Machine.

What worked for me, is
1. Uncheck the "Connected and Connect at power on" from Device Status.
2. Then Change the Device type from "Datastore ISO File to Client Device" Radio Button
3. and press OK to save the changes.

Note:- I was able to remove the mounted ISO only by directly logging to the ESXi at https://esxi-ip-address/ui

where it asks

"The guest operating system has locked the CD-ROM door and is probably using the CD-ROM, which can prevent the guest from recognizing media changes. If possible, eject the CD-ROM from inside the guest before disconnecting. Disconnect anyway and override the lock?"

You need to select yes to eject the CD-ROM and then remove the ISO file successfully.

a file I/O error has occurred while accessing vmware converter

While converting physical Windows 7 machine to Virtual machine of infrastructure type, I got this error. The error seems it is unable to read/write source or destination datastore.

I have installed VMware-converter-en-6.2.0-8466193 on Windows 7 physical machine with option locally selected. (not at server/client option)

All of my ESXi servers are connected to the vCenter Server, so I had to use vCenter Server's IP address to send this physical machine to the virtual world.

The issue i found was with the dns resolution to the vCenter Server's hostname. Since I am not using the same dns server on the Windows 7 client machine. So I updated the host entries manually for the vCenter Server's hosname to it IP address.

After adding dns eteries to the hostfile of windows 7, I am not getting this "a file I/O error has occurred while accessing vmware converter" and the migration has started.

How to import Putty Saved Connections to mRemoteNG

Just started using mRemoteNG and its being very cool to connect to different remote connection with different protocols e.g Window Remote Desktop, VNC to Linux, SSH, HTTP connection etc. from a single application.

As new user I configured some remote desktop connection which was quite easy to figure out. But when I wanted to add SSH connections, it came in my mind to import all of the saved connections in the putty. But I couldn't figure it out how can it be done, though it was quite easy and here are the steps.


Open your mRemoteNGCreate a folder if you want segregation of multiple networksCreate a new connectionEnter the IP address of remote server under connection in Config paneUnder the config pane, select protocol "SSH version 2".  Once you select protocol to SSH version 2 you are given option to import putty sessions, as shown in the snap below.


In the above snap, I have imported CSR-AWS session from my saved sessions in Putty.