03-Layer 2-LAN Switching Configuration Guide

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11-QinQ configuration
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Configuring QinQ

This document uses the following terms:

·          CVLAN—Customer network VLANs, also called inner VLANs, refer to VLANs that a customer uses on the private network.

·          SVLAN—Service provider network VLANs, also called outer VLANs, refer to VLANs that a service provider uses to transmit VLAN tagged traffic for customers.

About QinQ

802.1Q-in-802.1Q (QinQ) adds an 802.1Q tag to 802.1Q tagged customer traffic. It enables a service provider to extend Layer 2 connections across an Ethernet network between customer sites.

QinQ benefits

QinQ provides the following benefits:

·          Enables a service provider to use a single SVLAN to convey multiple CVLANs for a customer.

·          Enables customers to plan CVLANs without conflicting with SVLANs.

·          Enables customers to keep their VLAN assignment schemes unchanged when the service provider changes its VLAN assignment scheme.

·          Allows different customers to use overlapping CVLAN IDs. Devices in the service provider network make forwarding decisions based on SVLAN IDs instead of CVLAN IDs.

How QinQ works

As shown in Figure 1, a QinQ frame transmitted over the service provider network carries the following tags:

·          CVLAN tag—Identifies the VLAN to which the frame belongs when it is transmitted in the customer network.

·          SVLAN tag—Identifies the VLAN to which the QinQ frame belongs when it is transmitted in the service provider network. The service provider allocates the SVLAN tag to the customer.

The devices in the service provider network forward a tagged frame according to its SVLAN tag only. The CVLAN tag is transmitted as part of the frame's payload.

Figure 1 Single-tagged Ethernet frame header and double-tagged Ethernet frame header

 

As shown in Figure 2, customer A has remote sites CE 1 and CE 4. Customer B has remote sites CE 2 and CE 3. The CVLANs of the two customers overlap. The service provider assigns SVLANs 3 and 4 to customers A and B, respectively.

When a tagged Ethernet frame from CE 1 arrives at PE 1, the PE tags the frame with SVLAN 3. The double-tagged Ethernet frame travels over the service provider network until it arrives at PE 2. PE 2 removes the SVLAN tag of the frame, and then sends the frame to CE 4.

Figure 2 Typical QinQ application scenario

 

QinQ implementations

QinQ is enabled on a per-port basis. The link type of a QinQ-enabled port can be access, hybrid, or trunk. The QinQ tagging behaviors are the same across these types of ports.

A QinQ-enabled port tags all incoming frames (tagged or untagged) with the PVID tag.

·          If an incoming frame already has one tag, it becomes a double-tagged frame.

·          If the frame does not have any 802.1Q tags, it becomes a frame tagged with the PVID.

QinQ provides the most basic VLAN manipulation method to tag all incoming frames (tagged or untagged) with the PVID tag. To perform advanced VLAN manipulations, use VLAN mappings or QoS policies as follows:

·          To add different SVLANs for different CVLAN tags, use one-to-two VLAN mappings.

·          To use criteria other than the CVLAN ID to match packets for SVLAN tagging, use the QoS nest action. The QoS nest action can also be used with other actions in the same traffic behavior.

For more information about VLAN mappings, see "Configuring VLAN mapping." For more information about QoS, see ACL and QoS Configuration Guide.

Protocols and standards

·          IEEE 802.1Q, IEEE Standard for Local and Metropolitan Area Networks-Virtual Bridged Local Area Networks

·          IEEE 802.1ad, IEEE Standard for Local and Metropolitan Area Networks-Virtual Bridged Local Area Networks-Amendment 4: Provider Bridges

Restrictions and guidelines: QinQ configuration

When you configure QinQ, follow these restrictions and guidelines:

·          The inner 802.1Q tag of QinQ frames is treated as part of the payload. As a best practice to ensure correct transmission of QinQ frames, set the MTU to a minimum of 1504 bytes for each port on their forwarding path. This value is the sum of the default Ethernet interface MTU (1500 bytes) and the length (4 bytes) of a VLAN tag.

You can use a QoS policy, a VLAN mapping, and QinQ on a port for VLAN tag manipulation. If their settings conflict, the VLAN mapping has the highest priority, QinQ has the medium priority, and the QoS policy has the lowest priority.

Enabling QinQ

About enabling QinQ

Enable QinQ on customer-side ports of PEs. A QinQ-enabled port tags an incoming frame with its PVID.

Restrictions and guidelines

Before you enable or disable QinQ on a port, you must remove any VLAN mappings on the port. For more information about VLAN mapping, see Layer 2—LAN Switching Configuration Guide.

Procedure

1.        Enter system view.

system-view

2.        Enter Layer 2 Ethernet interface view or Layer 2 aggregate interface view.

interface interface-type interface-number

3.        Set the port link type.

port link-type { access | hybrid | trunk }

By default, the link type of a port is access.

4.        Configure the port to allow packets from its PVID to pass through.

¡  Assign the access port to the specified VLAN.

port access vlan vlan-id

By default, all access ports belong to VLAN 1.

The PVID of an access port is the VLAN to which the port belongs. The port sends packets from the VLAN untagged.

¡  Configure the hybrid port to send packets from its PVID untagged.

port hybrid vlan vlan-id-list untagged

By default, the hybrid port is an untagged member of the VLAN to which the port belongs when its link type is access.

¡  Configure trunk port to allow packets from its PVID to pass through.

port trunk permit vlan { vlan-id-list | all }

By default, a trunk port allows packets only from VLAN 1 to pass through.

5.        Enable QinQ on the port.

qinq enable

By default, QinQ is disabled on the port.

Configuring transmission for transparent VLANs

About transparent VLAN

You can exclude a VLAN (for example, the management VLAN) from the QinQ tagging action on a customer-side port. This VLAN is called a transparent VLAN.

Restrictions and guidelines

·          Do not configure any other VLAN manipulation actions for the transparent VLAN on the port.

·          Make sure all ports on the traffic path permit the transparent VLAN to pass through.

·          If you use both transparent VLANs and VLAN mappings on an interface, the transparent VLANs cannot be the following VLANs:

¡  Original or translated VLANs of one-to-one, one-to-two, and many-to-one VLAN mappings.

¡  Original or translated outer VLANs of two-to-two VLAN mappings.

Procedure

1.        Enter system view.

system-view

2.        Enter Layer 2 Ethernet interface view or Layer 2 aggregate interface view.

interface interface-type interface-number

3.        Set the port link type.

port link-type { hybrid | trunk }

By default, the link type of a port is access.

4.        Configure the port to allow packets from the transparent VLANs to pass through.

¡  Configure the hybrid port to allow packets from the transparent VLANs to pass through.

port hybrid vlan vlan-id-list { tagged | untagged }

By default, a hybrid port is an untagged member of the VLAN to which the port belongs when its link type is access.

¡  Configure the trunk port to allow packets from the transparent VLANs to pass through.

port trunk permit vlan { vlan-id-list | all }

By default, a trunk port allows packets only from VLAN 1 to pass through.

5.        Specify transparent VLANs for the port.

qinq transparent-vlan vlan-id-list

By default, transparent transmission is not configured for any VLANs.

Configuring the TPID for VLAN tags

About TPID

TPID identifies a frame as an 802.1Q tagged frame. The TPID value varies by vendor. On an H3C device, the TPID in the 802.1Q tag added on a QinQ-enabled port is 0x8100 by default, in compliance with IEEE 802.1Q. In a multi-vendor network, make sure the TPID setting is the same between directly connected devices so 802.1Q tagged frames can be identified correctly.

TPID settings include CVLAN TPID and SVLAN TPID.

A QinQ-enabled port uses the CVLAN TPID to match incoming tagged frames. An incoming frame is handled as untagged if its TPID is different from the CVLAN TPID.

SVLAN TPIDs are configurable on a per-port basis. A service provider-side port uses the SVLAN TPID to replace the TPID in outgoing frames' SVLAN tags and match incoming tagged frames. An incoming frame is handled as untagged if the TPID in its outer VLAN tag is different from the SVLAN TPID.

For example, a PE device is connected to a customer device that uses the TPID 0x8200 and to a provider device that uses the TPID 0x9100. For correct packet processing, you must set the CVLAN TPID and SVLAN TPID to 0x8200 and 0x9100 on the PE, respectively.

The TPID field is at the same position as the EtherType field in an untagged Ethernet frame. To ensure correct packet type identification, do not set the TPID value to any of the values listed in Table 1.

Table 1 Reserved EtherType 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

LLDP

0x88cc

802.1X

0x888e

802.1ag

0x8902

Cluster

0x88a7

Reserved

0xfffd/0xfffe/0xffff

 

Restrictions and guidelines

The TPID value in CVLAN tags is typically configured on PEs. The TPID value in SVLAN tags is typically configured on the service provider-side ports of PEs.

Configuring the TPID for CVLAN tags

1.        Enter system view.

system-view

2.        Set the TPID for CVLAN tags.

qinq ethernet-type customer-tag hex-value

By default, the TPID is 0x8100 for CVLAN tags.

Configuring the TPID for SVLAN tags

1.        Enter system view.

system-view

2.        Enter Layer 2 Ethernet interface view or Layer 2 aggregate interface view.

interface interface-type interface-number

3.        Set the TPID for SVLAN tags.

qinq ethernet-type service-tag hex-value

By default, the TPID is 0x8100 for SVLAN tags.

Display and maintenance commands for QinQ

Execute display commands in any view.

 

Task

Command

Display QinQ-enabled ports.

display qinq [ interface interface-type interface-number ]

 

QinQ configuration examples

Example: Configuring basic QinQ

Network configuration

As shown in Figure 3:

·          The service provider assigns VLAN 100 to Company A's VLANs 10 through 70.

·          The service provider assigns VLAN 200 to Company B's VLANs 30 through 90.

·          The devices between PE 1 and PE 2 in the service provider network use a TPID value of 0x8200.

Configure QinQ on PE 1 and PE 2 to transmit traffic in VLANs 100 and 200 for Company A and Company B, respectively.

For the QinQ frames to be identified correctly, set the SVLAN TPID to 0x8200 on the service provider-side ports of PE 1 and PE 2.

Figure 3 Network diagram

Procedure

1.        Configure PE 1:

# Configure GigabitEthernet 1/0/1 as a trunk port, and assign it to VLAN 100.

<PE1> system-view

[PE1] interface gigabitethernet 1/0/1

[PE1-GigabitEthernet1/0/1] port link-type trunk

[PE1-GigabitEthernet1/0/1] port trunk permit vlan 100

# Set the PVID of GigabitEthernet 1/0/1 to VLAN 100.

[PE1-GigabitEthernet1/0/1] port trunk pvid vlan 100

# Enable QinQ on GigabitEthernet 1/0/1.

[PE1-GigabitEthernet1/0/1] qinq enable

[PE1-GigabitEthernet1/0/1] quit

# Configure GigabitEthernet 1/0/2 as a trunk port, and assign it to VLANs 100 and 200.

[PE1] interface gigabitethernet 1/0/2

[PE1-GigabitEthernet1/0/2] port link-type trunk

[PE1-GigabitEthernet1/0/2] port trunk permit vlan 100 200

# Set the TPID value in the SVLAN tags to 0x8200 on GigabitEthernet 1/0/2.

[PE1-GigabitEthernet1/0/2] qinq ethernet-type service-tag 8200

[PE1-GigabitEthernet1/0/2] quit

# Configure GigabitEthernet 1/0/3 as a trunk port, and assign it to VLAN 200.

[PE1] interface gigabitethernet 1/0/3

[PE1-GigabitEthernet1/0/3] port link-type trunk

[PE1-GigabitEthernet1/0/3] port trunk permit vlan 200

# Set the PVID of GigabitEthernet 1/0/3 to VLAN 200.

[PE1-GigabitEthernet1/0/3] port trunk pvid vlan 200

# Enable QinQ on GigabitEthernet 1/0/3.

[PE1-GigabitEthernet1/0/3] qinq enable

[PE1-GigabitEthernet1/0/3] quit

2.        Configure PE 2:

# Configure GigabitEthernet 1/0/1 as a trunk port, and assign it to VLAN 200.

<PE2> system-view

[PE2] interface gigabitethernet 1/0/1

[PE2-GigabitEthernet1/0/1] port link-type trunk

[PE2-GigabitEthernet1/0/1] port trunk permit vlan 200

# Set the PVID of GigabitEthernet 1/0/1 to VLAN 200.

[PE2-GigabitEthernet1/0/1] port trunk pvid vlan 200

# Enable QinQ on GigabitEthernet 1/0/1.

[PE2-GigabitEthernet1/0/1] qinq enable

[PE2-GigabitEthernet1/0/1] quit

# Configure GigabitEthernet 1/0/2 as a trunk port, and assign it to VLANs 100 and 200.

[PE2] interface gigabitethernet 1/0/2

[PE2-GigabitEthernet1/0/2] port link-type trunk

[PE2-GigabitEthernet1/0/2] port trunk permit vlan 100 200

# Set the TPID value in the SVLAN tags to 0x8200 on GigabitEthernet 1/0/2.

[PE2-GigabitEthernet1/0/2] qinq ethernet-type service-tag 8200

[PE2-GigabitEthernet1/0/2] quit

# Configure GigabitEthernet 1/0/3 as a trunk port, and assign it to VLAN 100.

[PE2] interface gigabitethernet 1/0/3

[PE2-GigabitEthernet1/0/3] port link-type trunk

[PE2-GigabitEthernet1/0/3] port trunk permit vlan 100

# Set the PVID of GigabitEthernet 1/0/3 to VLAN 100.

[PE2-GigabitEthernet1/0/3] port trunk pvid vlan 100

# Enable QinQ on GigabitEthernet 1/0/3.

[PE2-GigabitEthernet1/0/3] qinq enable

[PE2-GigabitEthernet1/0/3] quit

3.        Configure the devices between PE 1 and PE 2:

# Set the MTU to a minimum of 1504 bytes for each port on the path of QinQ frames. (Details not shown.)

# Configure all ports on the forwarding path to allow frames from VLANs 100 and 200 to pass through without removing the VLAN tag. (Details not shown.)

Example: Configuring VLAN transparent transmission

Network configuration

As shown in Figure 4:

·          The service provider assigns VLAN 100 to a company's VLANs 10 through 50.

·          VLAN 3000 is the dedicated VLAN of the company on the service provider network.

Configure QinQ on PE 1 and PE 2 to provide Layer 2 connectivity for CVLANs 10 through 50 over the service provider network.

Configure VLAN transparent transmission for VLAN 3000 on PE 1 and PE 2 to enable the hosts in VLAN 3000 to communicate without using an SVLAN.

Figure 4 Network diagram

Procedure

1.        Configure PE 1:

# Configure GigabitEthernet 1/0/1 as a trunk port, and assign it to VLAN 100 and VLAN 3000.

<PE1> system-view

[PE1] interface gigabitethernet 1/0/1

[PE1-GigabitEthernet1/0/1] port link-type trunk

[PE1-GigabitEthernet1/0/1] port trunk permit vlan 100 3000

# Set the PVID of GigabitEthernet 1/0/1 to VLAN 100.

[PE1-GigabitEthernet1/0/1] port trunk pvid vlan 100

# Enable QinQ on GigabitEthernet 1/0/1.

[PE1-GigabitEthernet1/0/1] qinq enable

# Enable transparent transmission for VLAN 3000 on GigabitEthernet 1/0/1.

[PE1-GigabitEthernet1/0/1] qinq transparent-vlan 3000

[PE1-GigabitEthernet1/0/1] quit

# Configure GigabitEthernet 1/0/2 as a trunk port, and assign it to VLANs 100 and 3000.

[PE1] interface gigabitethernet 1/0/2

[PE1-GigabitEthernet1/0/2] port link-type trunk

[PE1-GigabitEthernet1/0/2] port trunk permit vlan 100 3000

[PE1-GigabitEthernet1/0/2] quit

2.        Configure PE 2:

# Configure GigabitEthernet 1/0/1 as a trunk port, and assign it to VLAN 100 and VLAN 3000.

<PE2> system-view

[PE2] interface gigabitethernet 1/0/1

[PE2-GigabitEthernet1/0/1] port link-type trunk

[PE2-GigabitEthernet1/0/1] port trunk permit vlan 100 3000

# Set the PVID of GigabitEthernet 1/0/1 to VLAN 100.

[PE1-GigabitEthernet1/0/1] port trunk pvid vlan 100

# Enable QinQ on GigabitEthernet 1/0/1.

[PE2-GigabitEthernet1/0/1] qinq enable

# Enable transparent transmission for VLAN 3000 on GigabitEthernet 1/0/1.

[PE2-GigabitEthernet1/0/1] qinq transparent-vlan 3000

[PE2-GigabitEthernet1/0/1] quit

# Configure GigabitEthernet 1/0/2 as a trunk port, and assign it to VLANs 100 and 3000.

[PE2] interface gigabitethernet 1/0/2

[PE2-GigabitEthernet1/0/2] port link-type trunk

[PE2-GigabitEthernet1/0/2] port trunk permit vlan 100 3000

3.        Configure the devices between PE 1 and PE 2:

# Set the MTU to a minimum of 1504 bytes for each port on the path of QinQ frames. (Details not shown.)

# Configure all ports on the forwarding path to allow frames from VLANs 100 and 3000 to pass through without removing the VLAN tag. (Details not shown.)