VLANs and Interfaces
There are several acronyms for interface types and components:
- IFD – Interface Physical Device
- IFL – Interface Logical Device
- IFF – Address Family
- IFA – Address Entry
Common interface names are:
- ge – Gigabit ethernet
- xe – 10G ethernet
- et – 100G ethernet
- ae – aggregated ethernet (LAG/etherchannel)
- vlan or irb – Logical interface based on VLAN
SFP’s can be of different speeds (eg, one may be 1G, and another may be 10G). So be aware that the interface names may change based on the SFP used.
The interface naming convention is type-x/y/z
- Type is ge, xe, etc
- x – FPC (aka linecard)
- y – module or slot
- z – port number
There are several names for management interfaces. Each platform may use different names. These include fxp0, em0, me0, and vme0. Some of these are physical, and others are virtual.
Some interfaces, such as pimd, pime, dsc, ipip, and gre, are special interfaces that are used for special purposes.
An unnumbered interface does not have an IP address. This helps conserve IP addresses.
All interfaces are configured with a unit. This contains logical interface information, like addressing. Sometimes this is used to create sub-interfaces. Physical properties (duplex, link speed, etc) are not configured in the unit.
Each unit may have one or more family. This is where the address is applied. For example, the inet family is for IPv4 addressing.
Addresses can be primary, preferred, or secondary. Primary addresses are used for locally sourced (broadcast or multicast) traffic, destined to a remote subnet. Preferred addresses are for locally sourced traffic to the local subnet.
Configuring voice ports means three main steps:
- Configuring a voice VLAN
- Configuring PoE
- Configuring LLDP-MED
Junos supports regex during configuration.
|show interfaces terse
|Get a simplified view of all interfaces on the system
|show interfaces <extensive>
|Get interface statistics
|set interfaces INTERFACE …
|Configures an interface
|set interfaces INTERFACE description
|Adds a description to an interface
|set interfaces INTERFACE unit NUMBER family inet address …
|Configures an IPv4 address
|set interfaces INTERFACE disable
|Disables an interface
|set vlans NAME vlan-id ID
|Defines a VLAN
|Shows a list of configured VLANs
|set interfaces INTERFACE unit 0 family ethernet-switching interface-mode <access|trunk>
|Sets a layer-2 port type (trunk port or access port)
|set interfaces INTERFACE unit 0 family ethernet-switching vlan members VLAN
|Adds VLANs to the port
|set interfaces INTERFACE vlan-tagging
|Enables VLAN tagging, which enables the use of units as subinterfaces
|set poe interface all
|Enables PoE on all interfaces
|set protocols lldp-med interface all
|Enables LLDP-MED on all interfaces
|Renames some configuration
|Deactivates any part of the config
|Copy some configuration from one place to another
|Replace some configuration
|Adds annotations into the config, like comments in code
Explanation of “ifd” and “ifl” indexes https://kb.juniper.net/InfoCenter/index?page=content&id=KB2820
Router Interfaces Overview https://www.juniper.net/documentation/en_US/junos/topics/concept/interfaces-interface-naming-overview.html
Performing Loopback Testing https://www.juniper.net/documentation/en_US/junos/topics/topic-map/ethernet-fast-and-gigabit-loopback-testing.html
Configuring Default, Primary, and Preferred Addresses and Interfaces https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/interfaces-configuring-default-primary-and-preferred-addresses-and-interfaces.html