Autodetection; Types Of Dynamic Interfaces - Juniper JUNOSE SOFTWARE 11.0.X - LINK LAYER CONFIGURATION GUIDE 4-1-2010 Configuration Manual

JUNOSe 11.0.x Link Layer Configuration Guide
You create and configure each layer of a static interface manually through an existing
configuration mechanism such as the command-line interface (CLI) or Simple Network
Management Protocol (SNMP).
Unlike static interfaces, dynamic interfaces are not restored through nonvolatile
storage (NVS) after a reboot.

Autodetection

The router performs autodetection, also referred to as autosensing, to determine the
layers of each dynamic interface. The autodetection process occurs when the router
conditionally constructs interface layers based on the encapsulation type of the
incoming packet.
Autodetection only uses system resources on demand based on what is detected in
the incoming packet. Dynamic interfaces are created as a result of traffic on the
interface. Dynamic interfaces can also be dynamically deleted without your
intervention, thereby enabling any consumed system resources to be returned.
Unlike dynamic interfaces, static interfaces always allocate system resources upon
creation, and always consume system resources, even when the interface is quiescent.

Types of Dynamic Interfaces

There are two types of dynamic interfaces: upper-layer and bulk-configured.
Bulk-configured dynamic interfaces enable you to dynamically create ATM 1483
subinterfaces and VLAN subinterfaces by bulk-configuring a range of identifiers.
There are two types of bulk-configured dynamic interfaces:
For more information, see "Configuring Dynamic Interfaces Using Bulk Configuration"
on page 573.
Upper-layer dynamic interfaces enable you to dynamically create the following
configurations:
NOTE: Ethernet interfaces in this chapter refer to any of these interfaces Fast Ethernet,
Gigabit Ethernet, or 10–Gigabit-Ethernet.
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Overview
ATM 1483 interfaces over static ATM AAL5 interface
VLAN subinterface over static VLAN major interface
Dynamic IP, PPPoE, PPP, MLPPP, and bridged Ethernet interfaces over a static
ATM 1483 interface
IP or PPPoE interfaces over VLAN interfaces and Ethernet, Gigabit Ethernet, and
10-Gigabit-Ethernet interfaces.