Table of Contents

Chapter 1 QinQ Configuration. 1-1

1.1 Introduction to QinQ.. 1-1

1.1.1 Understanding QinQ.. 1-1

1.1.2 Implementations of QinQ.. 1-2

1.1.3 Adjustable TPID Value of QinQ Frames. 1-2

1.2 Configuring Basic QinQ.. 1-4

1.3 Setting TPID Value for QinQ Frames. 1-5

1.4 QinQ Configuration Examples. 1-5

 

Chapter 1  QinQ Configuration

When configuring QinQ, go to these sections for information you are interested in:

l           QinQ Configuration

l           Configuring Basic QinQ

l           Setting TPID Value for QinQ Frames

l           QinQ Configuration Examples

1.1  Introduction to QinQ

1.1.1  Understanding QinQ

In the VLAN tag field defined in IEEE 802.1Q, only 12 bits are used for VLAN IDs, so a device can support a maximum of 4,094 VLANs. This is far from enough for isolating users in actual networks like metropolitan area networks (MANs).

QinQ is a simple and flexible Layer-2 VPN technology. It allows packets to be transmitted with double VLAN tags, allowing for up to 4094 × 4094 VLANs, thus satisfying the demand for large amount of VLANs in MANs.

QinQ encapsulates the private network VLAN tag in the public network VLAN tag, and enables the frame to be transmitted through the service provider backbone network (the public network) with double VLAN tags. The inner VLAN tag is the customer network VLAN tag while the outer one is the VLAN tag assigned by the service provider to the customer. In the public network, switches forward tagged frames based on the outer VLAN tag without checking the inner tag.

 

 

Figure 1-1 shows the structure of a single-tagged frame and a double-tagged frame.

Figure 1-1 Single-tagged frame structure vs. double-tagged Ethernet frame structure

QinQ delivers these benefits:

l           Saving public network VLAN ID resources.

l           Enabling customers to plan their own private network VLAN IDs, without running into conflicts with public network VLAN IDs.

l           Providing simple Layer 2 VPN solutions for small-sized MANs or Enterprise networks.

1.1.2  Implementations of QinQ

For S9500 series switches, the QinQ feature is implemented through enabling the basic QinQ feature on ports.

With the basic QinQ feature enabled on a port, when a frame arrives at the port, the port will tag it with the port’s default VLAN tag, regardless of whether the frame is tagged or untagged. If the received frame is already tagged, this frame becomes a double-tagged frame; if it is an untagged frame, it is tagged with the port’s default VLAN tag.

1.1.3  Adjustable TPID Value of QinQ Frames

A VLAN tag uses the tag protocol identifier (TPID) field to identify the protocol type of the tag. The value of this field, as defined in IEEE 802.1Q, is 0x8100.

Figure 1-2 shows the structure of a VLAN-tagged Ethernet frame defined in IEEE 802.1Q.

Figure 1-2 Structure of a VLAN-tagged Ethernet frame

 

 

On devices of different vendors, the TPID of the outer VLAN tag in QinQ frames may have different default values. For interoperability with other vendors’ devices, you are allowed to modify the TPID value in a QinQ frame so that the frame carries the TPID value of the specific vendor on the public network.

The TPID in an Ethernet frame has the same position with the protocol type field in a frame without a VLAN tag. To avoid chaotic packet forwarding and receiving, you cannot set the TPID value to any of the values in the table below.

Table 1-1 Protocol type values

Protocol type	Value
ARP	0x0806
PUP	0x0200
RARP	0x8035
IP	0x0800
IPv6	0x86DD
PPPoE	0x8863/0x8864
MPLS	0x8847/0x8848
IPX/SPX	0x8137
IS-IS	0x8000
LACP	0x8809
802.1x	0x888E
Cluster	0x88A7
Reserved	0xFFFD/0xFFFE/0xFFFF

 

1.2  Configuring Basic QinQ

Follow these steps to configure basic QinQ:

To do...		Use the command...	Remarks
Enter system view		system-view	—
Enter Ethernet interface view or port group view	Enter Ethernet interface view	interface interface-type interface-number	Use either command Configured in Ethernet interface view, the setting is effective on the current port only; configured in port group view, the setting is effective on all ports in the port group
	Enter interface group view	port-group { manual port-group-name | aggregation agg-id }
Enable the basic QinQ function for the Ethernet port or the port group		qinq enable	Required Disabled by default.

 

 

1.3  Setting TPID Value for QinQ Frames

Follow these steps to set the TPID value for QinQ frames:

To do...		Use the command...	Remarks
Enter system view		system-view	—
Enter Ethernet interface view or port group view	Enter Ethernet interface view	interface interface-type interface-number	Use either command Configured in Ethernet interface view, the setting is effective on the current port only; configured in port group view, the setting is effective on all ports in the port group
	Enter port group view	port-group { manual port-group-name | aggregation agg-id }
Set the TPID value in the outer VLAN tag that the port adds to frames		qinq ethernet-type hex-value	Optional 0x8100 by default

 

 

1.4  QinQ Configuration Examples

I. Network requirements

l           Provider A and Provider B are service provider network access devices.

l           Customer A and Customer B are customer network access devices.

l           Provider A and Provider B, belonging to VLAN 10 created in the service provider network, are interconnected through trunk ports.

l           In between Provider A and Provider B are devices with the TPID being 0x8200.

It is required that Customer A and Customer B can communicate with each other across the service provider network.

II. Network diagram

Figure 1-3 Network diagram for QinQ configuration

III. Configuration procedure

1)         Configuration on Provider A

# Enter system view.

<Sysname> system-view

[Sysname] vlan 10

[Sysname-vlan10] quit

# Enter Ethernet 1/1/2 port view.

[Sysname] interface ethernet 1/1/2

[Sysname-Ethernet1/1/2] port access vlan 10

# Enable the basic QinQ function on Ethernet 1/1/2.

[Sysname-Ethernet1/1/2] qinq enable

[Sysname-Ethernet1/1/2] quit

# Configure Ethernet 1/1/4 as a trunk port and configure the port to permit frames of VLAN 10.

[Sysname] interface ethernet 1/1/4

[Sysname-Ethernet1/1/4] port link-type trunk

[Sysname-Ethernet1/1/4] port trunk permit vlan 10

# Set the TPID value of Ethernet 1/1/4 to 0x8200 to ensure that Provider A can communicate with the other devices in the service provider network.

[Sysname-Ethernet1/1/4] qinq ethernet-type 8200

2)         Configuration on Provider B

# Enter system view.

<Sysname> system-view

[Sysname] vlan 10

[Sysname-vlan10] quit

# Enter Ethernet 1/1/2 port view.

[Sysname] interface ethernet 1/1/2

[Sysname-Ethernet1/1/2] port access vlan 10

# Enable the basic QinQ function on Ethernet 1/1/2.

[Sysname-Ethernet1/1/2] qinq enable

[Sysname-Ethernet1/1/2] quit

# Configure Ethernet 1/1/4 as a trunk port and configure the port to permit frames of VLAN 10.

[Sysname] interface ethernet 1/1/4

[Sysname-Ethernet1/1/4] port link-type trunk

[Sysname-Ethernet1/1/4] port trunk permit vlan 10

# Set the TPID value of Ethernet 1/1/4 to 0x8200 to ensure that Provider A can communicate with the other devices in the service provider network.

[Sysname-Ethernet1/1/4] qinq ethernet-type 8200

After the above configuration finishes, Customer A and Customer B should be able to exchange frames across the service provider network to communicate with other.