Tag Archives: 2.1d

2.1.d Implement and troubleshoot trunking

2.1.d [i] VTPv1, VTPv2, VTPv3, VTP pruning

You can limit the VLAN traffic passed between switches using VTP pruning.

Pruning increases available bandwidth by restricting flooded traffic to those trunk links that the traffic must use to access the destination devices. You can enable VTP pruning on a switch in VTP server mode using the vtp pruning command.
above from net acad ccnp switch lab manual
see also:
vlans-pruning-4 firewall.cx

2.1.d Implement and troubleshoot trunking

2.1.d [iii] Native VLAN

A frame in the VLAN-aware portion of the network that does not contain a VLAN tag is assumed to be flowing on the native (or default) VLAN. By default , the switch forwards untagged traffic in the native VLAN configured for the port. The native VLAN is VLAN 1 by default.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 1628-1629).  . Kindle Edition.

2.1.d Implement and troubleshoot trunking

2.1.d [ii] dot1Q

802.1Q tunneling enables service providers to use a single VLAN to support customers with multiple VLANs, while preserving customer VLAN IDs and keeping traffic in different customer VLANs segregated. A port configured to support 802.1Q tunneling is called a tunnel port. When you configure tunneling, you assign a tunnel port to a VLAN that you dedicate to tunneling, which then becomes a tunnel VLAN. To keep customer traffic segregated, each customer requires a separate tunnel VLAN, but that one tunnel VLAN supports all of the customer’s VLANs.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 1622-1626).  . Kindle Edition.

2.1.d Implement and troubleshoot trunking

2.1.d [i] VTPv1, VTPv2, VTPv3, VTP pruning

from: http://etherealmind.com/cisco-vtp-transparent-mode-discard-risk-transparent-client-server/

The Modes

A Switch in VTP Server mode will always actively participate in sending and receiving VTP and synchronising the VTP data file. Regardless of version.

A Switch in VTP Client mode will always actively participate in VTP data file synchronisation. Regardless of version.

A switch in VTP v1 Transparent Mode will not send, receive VTP data or participate in file synchronisation.

A switch in VTP v2 Transparent Mode will send, receive VTP data, but doesn’t participate in VTP file synchronisation.

The only configuration that DOES NOT pass VTP packets is a switch configured in VTPv1 Transparent Mode and VTPv3 in off mode.

For VTPv3, the difference is much clearer. VTPv3 has four modes: server, client, transparent and off. The difference between transparent and off is the termination of received VTP messages instead of relaying them. With VTP version 3, off mode can be configured globally or on a per port (for example trunk) base. The off mode was formerly only available with CAT OS. The configuration of off on an interface will apply to all VTP instances.

Also note that VTPv3 will propagate VLANs above 1024, while VTPv1 & 2 do not. Another historical artefact.