- play_arrow Understanding Layer 2 Networking
- play_arrow Configuring MAC Addresses
- play_arrow Configuring MAC Learning
- play_arrow Configuring MAC Accounting
- play_arrow Configuring MAC Notification
- play_arrow Configuring MAC Table Aging
- play_arrow Configuring Learning and Forwarding
- play_arrow Configuring 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
- play_arrow Configuring Restricted and Unrestricted Proxy ARP
- play_arrow Configuring Gratuitous ARP
- play_arrow Adjusting the ARP Aging Timer
- play_arrow 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
- play_arrow Configuring Layer 2 Virtual Switch Instances
- play_arrow Configuring Link Layer Discovery Protocol
- play_arrow Configuring Layer 2 Protocol Tunneling
- play_arrow Configuring Virtual Routing Instances
- play_arrow Configuring Routed VLAN Interfaces
- play_arrow Configuring Integrated Routing and Bridging
- play_arrow Configuring VLANS and VPLS Routing Instances
- play_arrow Configuring Multiple VLAN Registration Protocol (MVRP)
- play_arrow Configuring Ethernet Ring Protection Switching
- play_arrow Configuring Q-in-Q Tunneling and VLAN Translation
- play_arrow Configuring Redundant Trunk Groups
- play_arrow Configuring Proxy ARP
- play_arrow Configuring Layer 2 Interfaces on Security Devices
- play_arrow Configuring Security Zones and Security Policies on Security Devices
- play_arrow Configuring Ethernet Port Switching Modes on Security Devices
- play_arrow Configuring Ethernet Port VLANs in Switching Mode on Security Devices
- play_arrow Configuring Secure Wire on Security Devices
- play_arrow Configuring Reflective Relay on Switches
- play_arrow Configuring Edge Virtual Bridging
- play_arrow Troubleshooting Ethernet Switching
- play_arrow Configuration Statements and Operational Commands
Layer 3 Logical Interfaces
Understanding Layer 3 Logical Interfaces
A Layer 3 logical interface is a logical division of a physical interface that operates at the network level and therefore can receive and forward 802.1Q VLAN tags. You can use Layer 3 logical interfaces to route traffic among multiple VLANs along a single trunk line that connects a Juniper Networks switch to a Layer 2 switch. Only one physical connection is required between the switches. .
You can also use Layer 3 logical interfaces to provide alternative gateway addresses for smart DHCP relay. The logical tunnel (lt) and virtual loopback tunnel (vt) interfaces are not supported in logical interfaces.
To create Layer 3 logical interfaces on a switch, enable VLAN tagging, partition the physical interface into logical partitions, and bind the VLAN ID to the logical interface.
We recommend that you use the VLAN ID as the logical interface number when you configure the logical interface. QFX Series and EX4600 switches support a maximum of 4089 VLANs, which includes the default VLAN. You can assign VLAN ID in the range of 1 through 4094.
VLAN tagging places the VLAN ID in the frame header, allowing each physical interface to handle multiple VLANs. When you configure multiple VLANs on an interface, you must also enable tagging on that interface. Junos OS on switches supports a subset of the 802.1Q standard for receiving and forwarding routed or bridged Ethernet frames with single VLAN tags and running Virtual Router Redundancy Protocol (VRRP) over 802.1Q-tagged interfaces.
Configuring a Layer 3 Logical Interface
Devices use Layer 3 logical interfaces to divide a physical interface into multiple logical interfaces, each corresponding to a VLAN. Layer 3 logical interfaces route traffic between subnets.
To configure Layer 3 logical interfaces, enable VLAN tagging and partition one or more physical ports into multiple logical interfaces, each corresponding to a VLAN ID.
Before you begin, make sure you set up your VLANs. See Configuring VLANs on Switches.
To configure Layer 3 logical interfaces:
Verifying That Layer 3 Logical Interfaces Are Working
Purpose
After configuring Layer 3 logical interfaces, verify that they are set up properly and transmitting data.
Action
To determine if you have successfully created the logical interfaces and the links are up:
content_copy zoom_out_map[edit interfaces] user@switch> show interfaces interface-name terse Interface Admin Link Proto Local Remote ge-0/0/0 up up ge-0/0/0.0 up up inet 10.0.1.1/24 ge-0/0/0.1 up up inet 10.0.2.2/24 ge-0/0/0.2 up up inet 10.0.3.3/24 ge-0/0/0.3 up up inet 10.0.4.4/24 ge-0/0/0.4 up up inet 10.0.5.5/24 ge-0/0/0.32767 up up
Use the
pingcommand from a device on one subnet to an address on another subnet to determine if packets were transmitted correctly on the logical interface VLANs:content_copy zoom_out_mapuser@switch> ping ip-address PING 10.1.1.1 (10.1.1.1): 56 data bytes 64 bytes from 10.1.1.1: icmp_seq=0 ttl=64 time=0.157 ms 64 bytes from 10.1.1.1: icmp_seq=1 ttl=64 time=0.238 ms 64 bytes from 10.1.1.1: icmp_seq=2 ttl=64 time=0.255 ms 64 bytes from 10.1.1.1: icmp_seq=3 ttl=64 time=0.128 ms --- 10.1.1.1 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss
Meaning
The output confirms that the logical interfaces have been created and the links are up.
