Configure a Sub-Interface
Let us learn to configure a sub-interface.
You can create sub-interfaces on physical
or virtual interfaces and use bypass pairs for Local Area Networks (LANs)
and private and public Wide Area Networks (WANs). A sub-interface
is created by dividing one physical interface into multiple virtual
interfaces.
The parent interface can be an Ethernet port,
a virtual port, or a bypass pair that does not contain any configuration.
You cannot configure a sub-interface on the controller port or any
interfaces or bypass pairs already configured with loopback as a
member with PPPoE or standard VPNs.
- If the sub-interface is on a bypass pair and the sub-interface is used for internet or private WAN, then the sub-interface is created on the bypass pair's WAN port.
- If the sub-interface is on a bypass pair and the sub-interface is used for LAN, then the sub-interface is created on the LAN port of the bypass pair.
Multiple sub-interfaces may be configured
on a physical or virtual interface or bypass pairs. If multiple
interfaces are configured, a VLAN ID is required to create and uniquely
identify each sub-interface.
Pre-5.1.x
device releases,
LAN sub-interfaces may only be used for the following branch services. Release
5.1.1 and later
device releases enable LAN sub-interfaces to
forward user and application traffic in addition to the following
branch services.- DHCP Server
- DHCP Relay
- DHCP Relay source interface
- SNMP Agent
- SNMP Trap source interface
- Ping to and from the interface IP
- Secure Socket Shell (SSH) access to the ION device CLI commands
You
cannot configure a Virtual Interface (VI) on a sub-interface. DHCP
Relay and DHCP server cannot be configured on the same sub-interface.
DHCP Relay when configured on a sub-interface:
- Can listen to broadcast and unicast DHCP requests.
- Can use the sub-interface as the source interface to reach DHCP servers.
When SNMP is configured on a sub-interface:
- An SNMP Agent can listen to unicast requests.
- An SNMP Trap can use the sub-interface as the source interface to reach SNMP servers.
- From , select a device and clickConfigure the device.
- Select theInterfacestab.
- Select a port.
- ForAdmin Up, selectYes.
- (Optional)Enter aDescription.
- LeaveUse This Port ToandConfigurationblank.
- Save Port.
- Click theSub-Interfacestab.
- Select+ Add Sub-Interfaceto create a new sub-interface.
- ForAdmin Up, selectYes.
- (Optional)Enter aDescription.
- FromUse This Sub-Interface Todrop-down, select the option applicable to the interface you are configuring;Connect to Internet, orPeer with a Network.
- ForCircuit Label, select circuits and clickDone.
- Enter aVLAN ID.The VLAN ID can be updated or changed.
- Mark the Native VLAN box if the identified sub-interface is used for native VLAN.Only one sub-interface of a parent interface can be configured for native VLAN. By default, the native VLAN box is unchecked.DNS Servers need to be entered for Internet and Private WAN but not for LAN.
- (Optional)If DHCP Relay functions are required, chooseDHCPfor theConfigurationfield. ChangeAdd DHCP RelayfromNotoYes.
- SelectCreate Sub-Interface.
