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play_arrow Understanding Layer 2 Networking
- Layer 2 Networking
play_arrow Configuring MAC Addresses
- MAC Addresses
play_arrow Configuring MAC Learning
- MAC Learning
play_arrow Configuring MAC Accounting
- MAC Accounting
play_arrow Configuring MAC Notification
- MAC Notification
play_arrow Configuring MAC Table Aging
- MAC Table Aging
play_arrow Configuring Learning and Forwarding
- Layer 2 Forwarding Tables
play_arrow Configuring Bridging and VLANs
- Bridging and VLANs
play_arrow Configuring 802.1Q VLANs
- 802.1Q VLANs Overview
- 802.1Q VLAN IDs and Ethernet Interface Types
- Configuring Dynamic 802.1Q VLANs
- Enabling VLAN Tagging
- Configuring Tagged Interface with multiple tagged vlans and native vlan
- Sending Untagged Traffic Without VLAN ID to Remote End
- Configuring Tag Protocol IDs (TPIDs) on QFX Series Switches
- Configuring Flexible VLAN Tagging on PTX Series Packet Transport Routers
- Configuring an MPLS-Based VLAN CCC with Pop, Push, and Swap and Control Passthrough
- Binding VLAN IDs to Logical Interfaces
- Associating VLAN IDs to VLAN Demux Interfaces
- Configuring VLAN and Extended VLAN Encapsulation
- Configuring a Layer 2 VPN Routing Instance on a VLAN-Bundled Logical Interface
- Example: Configuring a Layer 2 VPN Routing Instance on a VLAN-Bundled Logical Interface
- Specifying the Interface Over Which VPN Traffic Travels to the CE Router
- Configuring Access Mode on a Logical Interface
- Configuring a Logical Interface for Trunk Mode
- Configuring the VLAN ID List for a Trunk Interface
- Configuring a Trunk Interface on a Bridge Network
- Configuring a VLAN-Bundled Logical Interface to Support a Layer 2 VPN Routing Instance
- Configuring a VLAN-Bundled Logical Interface to Support a Layer 2 VPN Routing Instance
- Configuring a Layer 2 Circuit on a VLAN-Bundled Logical Interface
- Example: Configuring a Layer 2 Circuit on a VLAN-Bundled Logical Interface
- Guidelines for Configuring VLAN ID List-Bundled Logical Interfaces That Connect CCCs
- Specifying the Interface to Handle Traffic for a CCC
- Specifying the Interface to Handle Traffic for a CCC Connected to the Layer 2 Circuit
play_arrow Configuring Static ARP Table Entries
- Static ARP Table Entries Overview
- Static ARP Entries on Ethernet Interfaces
- Configuring Static ARP Table Entries For Mapping IP Addresses to MAC Addresses
- Example: Configuring Static ARP Entries on Ethernet Interfaces
play_arrow Configuring Restricted and Unrestricted Proxy ARP
- Restricted and Unrestricted Proxy ARP Overview
- Configuring Restricted and Unrestricted Proxy ARP
play_arrow Configuring Gratuitous ARP
- Configuring Gratuitous ARP
play_arrow Adjusting the ARP Aging Timer
- Adjusting the ARP Aging Timer
play_arrow Configuring Tagged VLANs
- Configuring Tagged VLANs
play_arrow Stacking and Rewriting Gigabit Ethernet VLAN Tags
- Stacking and Rewriting Gigabit Ethernet VLAN Tags Overview
- Stacking and Rewriting Gigabit Ethernet VLAN Tags
- Configuring Frames with Particular TPIDs to Be Processed as Tagged Frames
- Configuring Tag Protocol IDs (TPIDs) on PTX Series Packet Transport Routers
- Configuring Stacked VLAN Tagging
- Configuring Dual VLAN Tags
- Configuring Inner and Outer TPIDs and VLAN IDs
- Stacking a VLAN Tag
- Stacking Two VLAN Tags
- Removing a VLAN Tag
- Removing the Outer and Inner VLAN Tags
- Removing the Outer VLAN Tag and Rewriting the Inner VLAN Tag
- Rewriting the VLAN Tag on Tagged Frames
- Rewriting a VLAN Tag on Untagged Frames
- Rewriting a VLAN Tag and Adding a New Tag
- Rewriting the Inner and Outer VLAN Tags
- Examples: Stacking and Rewriting Gigabit Ethernet IQ VLAN Tags
- Understanding Transparent Tag Operations and IEEE 802.1p Inheritance
- Understanding swap-by-poppush
- Configuring IEEE 802.1p Inheritance push and swap from the Transparent Tag
play_arrow Configuring Private VLANs
- Private VLANs
- Understanding Private VLANs
- Bridge Domains Setup in PVLANs on MX Series Routers
- Bridging Functions With PVLANs
- Flow of Frames on PVLAN Ports Overview
- Guidelines for Configuring PVLANs on MX Series Routers
- Configuring PVLANs on MX Series Routers in Enhanced LAN Mode
- Example: Configuring PVLANs with Secondary VLAN Trunk Ports and Promiscuous Access Ports on a QFX Series Switch
- IRB Interfaces in Private VLANs on MX Series Routers
- Guidelines for Configuring IRB Interfaces in PVLANs on MX Series Routers
- Forwarding of Packets Using IRB Interfaces in PVLANs
- Configuring IRB Interfaces in PVLAN Bridge Domains on MX Series Routers in Enhanced LAN Mode
- Example: Configuring an IRB Interface in a Private VLAN on a Single MX Series Router
play_arrow Configuring Layer 2 Bridging Interfaces
- Layer 2 Bridging Interfaces Overview
- Configuring Layer 2 Bridging Interfaces
- Example: Configuring the MAC Address of an IRB Interface
play_arrow Configuring Layer 2 Virtual Switch Instances
- Layer 2 Virtual Switch Instances
play_arrow Configuring Link Layer Discovery Protocol
- LLDP Overview
- Configuring LLDP
- Example: Configuring LLDP
- Configuring the Transmission of Maximum VLAN Name TLVs in LLDP
- LLDP Operational Mode Commands
- Tracing LLDP Operations
play_arrow Configuring Layer 2 Protocol Tunneling
- Layer 2 Protocol Tunneling (L2PT)
play_arrow Configuring Virtual Routing Instances
- Virtual Routing Instances
play_arrow Configuring Layer 3 Logical Interfaces
- Layer 3 Logical Interfaces
play_arrow Configuring Routed VLAN Interfaces
- Routed VLAN Interfaces
play_arrow Configuring Integrated Routing and Bridging
- Integrated Routing and Bridging
play_arrow Configuring VLANS and VPLS Routing Instances
- VLANs and VPLS Routing Instances
play_arrow Configuring Multiple VLAN Registration Protocol (MVRP)
- Multiple VLAN Registration Protocol
play_arrow Configuring Ethernet Ring Protection Switching
- Example: Configuring Ethernet Ring Protection Switching on EX Series Switches
- Example: Configuring Ethernet Ring Protection Switching on QFX Series and EX Series Switches Supporting ELS
play_arrow Configuring Q-in-Q Tunneling and VLAN Translation
- Configuring Q-in-Q Tunneling and VLAN Q-in-Q Tunneling and VLAN Translation
play_arrow Configuring Redundant Trunk Groups
- Redundant Trunk Groups
- Q-in-Q Support on Redundant Trunk Links Using LAGs with Link Protection
play_arrow Configuring Proxy ARP
- Proxy ARP
play_arrow Configuring Layer 2 Interfaces on Security Devices
- Layer 2 Interfaces on Security Devices
play_arrow Configuring Security Zones and Security Policies on Security Devices
- Security Zones and Security Policies on Security Devices
play_arrow Configuring Ethernet Port Switching Modes on Security Devices
- Ethernet Port Switching Modes on Security Devices
play_arrow Configuring Ethernet Port VLANs in Switching Mode on Security Devices
- Ethernet Port VLANs in Switching Mode on Security Devices
play_arrow Configuring Secure Wire on Security Devices
- Secure Wire on Security Devices
play_arrow Configuring Reflective Relay on Switches
- Reflective Relay on Switches
play_arrow Configuring Edge Virtual Bridging
- Edge Virtual Bridging
play_arrow Troubleshooting Ethernet Switching
- Troubleshooting Ethernet Switching
- Troubleshooting Ethernet Switching on EX Series Switches
play_arrow Configuration Statements and Operational Commands
- Junos CLI Reference Overview

list Table of Contents

English

Q-in-Q Support on Redundant Trunk Links Using LAGs with Link Protection

date_range 20-Dec-24

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Understanding Q-in-Q Support on RTGs Using LAGs with Link Protection

Redundant trunk links provide a simple solution for network recovery when a trunk port on a switch goes down. In that case, traffic is routed to another trunk port, keeping network convergence time to a minimum.

Note:

For information about using redundant trunk links in a legacy redundant trunk groups (RTG) setup—that is, an RTG configuration that does not support Q-in-Q or service-provider configurations—see Understanding Redundant Trunk Links (Legacy RTG Configuration).

You can use this feature of redundant trunk links (or RTG) with Q-in-Q support using LAGs with link protection in both service provider and enterprise configurations.

This feature of RTG with Q-in-Q support includes support for the following items that are not supported in legacy RTG configurations:

Configuration of flexible VLAN tagging on the same LAG that supports the redundant links configurations
Multiple redundant-link configurations on one physical interface
Multicast convergence

The redundant trunk link configuration (also known as a “redundant trunk group (RTG) configuration”) contains two links: a primary or active link and a secondary link. If the primary link fails, the secondary link automatically starts forwarding data traffic without waiting for normal spanning-tree protocol convergence.

Data traffic is forwarded only on the primary link. Data traffic received on the secondary link is dropped.

While data traffic is blocked on the secondary link, Layer 2 control traffic is still permitted. For example, you can run an LLDP session between two switches on the secondary link.

Rapid Spanning Tree Protocol (RSTP) is enabled by default on the switches to create a loop-free topology, but an interface cannot be in both a redundant trunk link and in a spanning-tree protocol topology at the same time. You must disable RSTP on an interface if a redundant trunk link is configured on that interface. Spanning-tree protocols can, however, continue operating on other interfaces on those switches.

Figure 1: Q-in-Q with Redundant Trunk Links Using LAGs with Link Protection, with Subgroups

The top of Figure 1 shows three switches in a topology for redundant trunk links on a LAG with flexible VLAN tagging. This particular configuration also includes subgroups that contain multiple links—there can be just two subgroups on the LAG, and both subgroups must have the same number of links.

Note:

The topology shown in Figure 1 applies only to the first of the three configurations described later in this topic. See Configuring Redundant Trunk Links on an LACP LAG (N:N Link Protection with Subgroups). While the remaining configuration tasks share some elements of the first task, some absolute values provided in each task are unique to that task—for example, the ingress interface has a different value in each task.

Switch 3 is connected to Switch 1 through Subgroup 1 and to Switch 2 through Subgroup 2. Subgroups 1 and 2 are in an aggregated Ethernet bundle, or link aggregation group (LAG), with interface name ae0. Subgroup 1 is designated as the primary link, and Subgroup 2 is designated as the secondary link. Traffic flows between Switch 3 and Switch 1 through Subgroup 1. While Subgroup 1 is active, Subgroup 2 blocks data traffic.

The bottom of Figure 1 illustrates how the redundant trunk link topology works when the primary link goes down.

When Subgroup 1 between Switch 1 and Switch 3 goes down, Subgroup 2 takes over as the primary (active) link. Traffic flows between Switch 3 and Switch 2 through Subgroup 2.

Note:

Here is how multicast convergence works in a topology such as the one illustrated in the preceding figure:

With LAG ae0 being a multicast router port, all IGMP join messages received on Switch 3 are forwarded to Switch 1.
When the link between Switch 3 and Switch 1 goes down, traffic for the multicast source received on Switch 2 is flooded to all ports in the VLAN.
When the primary link goes down, an IGMP general query is sent by Switch 3 to all ports in the VLAN, and the IGMP reports received from clients are forwarded to Switch 2, through which learning happens; thus, multicast convergence is achieved.

Configuring Redundant Trunk Links on a LAG with Link Protection and Flexible VLAN Tagging

There are several variations on the configuration of redundant trunk links on a LAG with link protection and with flexible VLAN tagging.

Note:

For illustration purposes only, the following configuration tasks show absolute values, such as ge-0/0/30, rather than variables such as interface-name.

Configuring Redundant Trunk Links on an LACP LAG (N:N Link Protection with Subgroups)
Configuring Redundant Trunk Links on a Static LAG (1:1 Link Protection)
Configuring Redundant Trunk Links on a LAG with Multiple Logical Interfaces (1:1 Link Protection )
Verifying That Redundant Trunk Links Are Available on the LAG and Viewing Active Links

Configuring Redundant Trunk Links on an LACP LAG (N:N Link Protection with Subgroups)

Configure the ingress interface:

content_copy zoom_out_map
set interfaces ge-0/0/30 enable
set interfaces ge-0/0/30 flexible-vlan-tagging
set interfaces ge-0/0/30 encapsulation extended-vlan-bridge
set interfaces ge-0/0/30 unit 30 vlan-id 30
set interfaces ge-0/0/30 unit 30 input-vlan-map push
set interfaces ge-0/0/30 unit 30 output-vlan-map pop
set vlans qinqvlan interface ge-0/0/30.30

Assign interfaces to the LAG, and assign those interfaces to two link-protection subgroups:

content_copy zoom_out_map
set interfaces ge-0/0/14 ether-options 802.3ad ae0
set interfaces ge-0/0/15 ether-options 802.3ad ae0
set interfaces ge-0/0/16 ether-options 802.3ad ae0
set interfaces ge-0/0/17 ether-options 802.3ad ae0
set interfaces ge-0/0/14 ether-options 802.3ad link-protection-sub-group subg1
set interfaces ge-0/0/15 ether-options 802.3ad link-protection-sub-group subg1
set interfaces ge-0/0/16 ether-options 802.3ad link-protection-sub-group subg2
set interfaces ge-0/0/17 ether-options 802.3ad link-protection-sub-group subg2

Assign LACP values, configure redundant trunk links (using the rtg-config statement) on the LAG, set one subgroup as primary and one as backup, and configure Q-in-Q on the LAG:

content_copy zoom_out_map
set interfaces ae0 flexible-vlan-tagging
set interfaces ae0 encapsulation extended-vlan-bridge
set interfaces ae0 aggregated-ether-options lacp active
set interfaces ae0 aggregated-ether-options lacp periodic fast
set interfaces ae0 aggregated-ether-options lacp link-protection rtg-config
set interfaces ae0 aggregated-ether-options lacp system-id 00:00:00:01:00:02
set interfaces ae0 aggregated-ether-options link-protection-sub-group subg1 primary
set interfaces ae0 aggregated-ether-options link-protection-sub-group subg2 backup
set interfaces ae0 unit 300 vlan-id 40
set vlans qinqvlan interface ae0.300

Configuring Redundant Trunk Links on a Static LAG (1:1 Link Protection)

Configure the ingress interface:

content_copy zoom_out_map
set interfaces ge-1/0/0 flexible-vlan-tagging
set interfaces ge-1/0/0 encapsulation extended-vlan-bridge
set interfaces ge-1/0/0 unit 4001 vlan-id-list 1-100
set interfaces ge-1/0/0 unit 4001 input-vlan-map push
set interfaces ge-1/0/0 unit 4001 output-vlan-map pop

Assign interfaces to the LAG, configure redundant trunk links (using the rtg-config statement) on the LAG, and configure Q-in-Q on the LAG:

content_copy zoom_out_map
set interfaces ae0 enable
set interfaces ae0 flexible-vlan-tagging
set interfaces ae0 encapsulation extended-vlan-bridge
set interfaces ae0 aggregated-ether-options link-protection rtg-config
set interfaces ae0 aggregated-ether-options minimum-links 1
set interfaces ae0 unit 300 vlan-id 40
set vlans qinqvlan interface ae0.300
set vlans qinqvlan interface ge-1/0/0.4001

Assign the member interfaces on the LAG and assign the two redundant trunk links to the interfaces; set one of the links as primary and one as backup:

content_copy zoom_out_map
set interfaces ge-1/0/22 enable
set interfaces ge-1/0/22 ether-options 802.3ad ae0
set interfaces ge-1/0/22 ether-options 802.3ad primary
set interfaces ge-1/0/23 enable
set interfaces ge-1/0/23 ether-options 802.3ad ae0
set interfaces ge-1/0/23 ether-options 802.3ad backup

Configuring Redundant Trunk Links on a LAG with Multiple Logical Interfaces (1:1 Link Protection )

Configure the ingress interface:

content_copy zoom_out_map
set interfaces ge-0/0/0 flexible-vlan-tagging
set interfaces ge-0/0/0 encapsulation extended-vlan-bridge
set interfaces ge-0/0/0 unit 4001 vlan-id-list 1-100
set interfaces ge-0/0/0 unit 4001 input-vlan-map push
set interfaces ge-0/0/0 unit 4001 output-vlan-map pop
set interfaces ge-0/0/0 unit 5001 vlan-id-list 101-130
set interfaces ge-0/0/0 unit 5001 input-vlan-map push
set interfaces ge-0/0/0 unit 5001 output-vlan-map pop

Assign interfaces to the LAG, configure redundant trunk links (using the rtg-config statement) on the LAG, and configure Q-in-Q on the LAG:

content_copy zoom_out_map
set interfaces ae0 enable
set interfaces ae0 flexible-vlan-tagging
set interfaces ae0 encapsulation extended-vlan-bridge
set interfaces ae0 aggregated-ether-options link-protection rtg-config
set interfaces ae0 aggregated-ether-options minimum-links 1
set interfaces ae0 unit 300 vlan-id 40
set interfaces ae0 unit 400 vlan-id 110
set vlans qinqvlan interface ae0.300
set vlans qinqvlan interface ge-0/0/0.4001
set vlans qinqvlan1 interface ae0.400
set vlans qinqvlan1 interface ge-0/0/0.5001

Assign the member interfaces on the LAG and assign the two redundant trunk links to the member interfaces; set one of the links as primary and one as backup:

content_copy zoom_out_map
set interfaces ge-0/0/5 enable
set interfaces ge-0/0/5 ether-options 802.3ad ae0
set interfaces ge-0/0/5 ether-options 802.3ad primary
set interfaces ge-0/0/6 enable
set interfaces ge-0/0/6 ether-options 802.3ad ae0
set interfaces ge-0/0/6 ether-options 802.3ad backup

Verifying That Redundant Trunk Links Are Available on the LAG and Viewing Active Links

Purpose
Action

Purpose

Verify that the redundant trunk links are available on the LAG, and see which interfaces are configured as the primary (active) links.

Action

Use the following show commands:

show mac-refresh interface-name—Display whether redundant trunk links on a LAG with link protection are enabled on the specified interface.
show interfaces ge interface-name extensive or show interfaces xe interface-name extensive—On a static LAG, display which interface is set as the primary member.
show lacp interfaces—On an LACP LAG, display which member interfaces are active and which are down.

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Ethernet Switching User Guide

ON THIS PAGE

Q-in-Q Support on Redundant Trunk Links Using LAGs with Link Protection

Understanding Q-in-Q Support on RTGs Using LAGs with Link Protection

Configuring Redundant Trunk Links on a LAG with Link Protection and Flexible VLAN Tagging

Configuring Redundant Trunk Links on an LACP LAG (N:N Link Protection with Subgroups)

Configuring Redundant Trunk Links on a Static LAG (1:1 Link Protection)

Configuring Redundant Trunk Links on a LAG with Multiple Logical Interfaces (1:1 Link Protection )

Verifying That Redundant Trunk Links Are Available on the LAG and Viewing Active Links

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Ethernet Switching User Guide

ON THIS PAGE

Q-in-Q Support on Redundant Trunk Links Using LAGs with Link Protection

Understanding Q-in-Q Support on RTGs Using LAGs with Link Protection

Configuring Redundant Trunk Links on a LAG with Link Protection and Flexible VLAN Tagging

Configuring Redundant Trunk Links on an LACP LAG (N:N Link Protection with Subgroups)

Configuring Redundant Trunk Links on a Static LAG (1:1 Link Protection)

Configuring Redundant Trunk Links on a LAG with Multiple Logical Interfaces (1:1 Link Protection )

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Verifying That Redundant Trunk Links Are Available on the LAG and Viewing Active Links

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