What is second dot1q?
What is second dot1q?
Router(config-subif)# encapsulation dot1q 100 second-dot1q 200. (Required) Enables the 802.1Q encapsulation of traffic on a specified subinterface in a VLAN. • Use the second-dot1q keyword and the vlan-id argument to specify the VLAN tags to be terminated on the subinterface.
What is the use of encapsulation dot1q?
IEEE802.1Q, often referred to as DOT1Q or 1Q, is the networking standard that supports virtual LANs (VLANs) on an IEEE 802.3 Ethernet network. It is the most widely used encapsulation method for VLAN tagging.
What is inner VLAN?
“Inner tags” contain VLAN information that belong to the traffic of the NSP’s customers. Though Q-in-Q/802.1ad was designed originally for NSPs to add/remove transparently to a customer (so called ‘pushing’ and ‘popping’ of outer tags) it is routinely utilised to carry a range of VLANs across a single VXC.
What is VLAN tunneling?
802.1Q tunneling enables service providers to use a single VLAN to support customers who have 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.
Why is VLAN trunking used?
Why is trunking important to VLAN configuration? With VLAN trunking, it’s possible to extend a VLAN across the network. When you implement multiple VLANs across a network, trunk links are necessary to ensure that VLAN signals remain properly segregated for each to reach their intended destination.
Why is QinQ used?
The general purpose of QinQ is to allow frames from multiple customers to be forwarded (or tunneled) through another topology (provider network) using service VLANs or S-VLANs.
What is QinQ protocol?
IEEE 802.1ad is an Ethernet networking standard informally known as QinQ as an amendment to IEEE standard IEEE 802.1Q-1998 that was incorporated into the base 802.1Q standard in 2011. QinQ allows multiple VLAN tags in an Ethernet frame; together these tags constitute a tag stack.
What is inner VLAN and outer VLAN?
Within an Ethernet Frame, these two tags are often known as “Inner tag” and “Outer tag”. “Inner tags” contain VLAN information that belong to the traffic of the NSP’s customers. The “Outer tags” contains information relating to the NSP’s VLAN networks.
What does the encapsulation Dot1q command do?
The encapsulation dot1q command is used to configure Q-in-Q termination on a subinterface. The command accepts an Outer VLAN ID and one or more Inner VLAN IDs. The outer VLAN ID always has a specific value, while inner VLAN ID can either be a specific value or a range of values.
How to use Dot1q in Cisco router?
Encapsulation Dot1Q Command on CISCO Router/Switch 1 Command 2 Use. Allows you to use a router interface as a trunk port to a switch. 3 Syntax 4 Option. Sets the vlan on the subinterface to act as the native VLAN. 5 Example. In the below example we will configure a basic “router on a stick” configuration.
What is the IEEE 802.1Q encapsulation command?
IEEE 802.1Q encapsulation is configurable on Ethernet and EtherChannel interfaces. IEEE 802.1Q is a standard protocol for interconnecting multiple switches and routers and for defining VLAN topologies. Use the encapsulation dot1q command in subinterface range configuration mode to apply a VLAN ID to the subinterface.
When to use the second Dot1q any command?
If you use the encapsulation dot1q second-dot1q any command on a subinterface not configured for EoMPLS tunneling, all incoming packets are dropped without generating an error message. The any keyword in the second-dot1q command is supported only for Point-to-Point Protocol over Ethernet ( PPPoE) QinQ traffic.
