Juniper Networks glossary
Key Juniper Networks certification terms and acronyms.
Definitions are AI-assisted and reviewed for general accuracy — verify critical details against Juniper Networks's official documentation.
ASNAutonomous System Number
A unique number assigned to an autonomous system for use in BGP routing to identify and distinguish routing domains.
BGPBorder Gateway Protocol
A path-vector exterior gateway routing protocol defined in RFC 4271 used to exchange routing information between autonomous systems on the internet.
candidate configuration
A temporary, editable copy of the device configuration in Junos that must be committed before changes take effect on the active configuration.
CLICommand-Line Interface
The text-based interface used to configure, monitor, and manage Junos devices through operational and configuration modes.
commit
The Junos command that activates the candidate configuration, replacing the active configuration after a syntax and semantic check.
FIBForwarding Information Base
The forwarding table installed in the PFE that contains the active routes selected from the RIB used to make packet-forwarding decisions.
firewall filter
A Junos stateless packet filter applied to interfaces that matches traffic based on defined terms and takes actions such as accept, discard, or reject.
interface
A logical or physical network port on a Junos device identified by media type, FPC, PIC, and port number (e.g., ge-0/0/0).
IS-ISIntermediate System to Intermediate System
A link-state IGP routing protocol defined in ISO 10589 that uses a two-level hierarchy of areas and is commonly deployed in service provider networks.
J-WebJuniper Web Interface
The browser-based graphical management interface built into Junos that provides device configuration, monitoring, and troubleshooting capabilities.
Junos OSJuniper Networks Operating System
The FreeBSD-based network operating system developed by Juniper Networks that runs on routers, switches, and firewalls.
logical unit
A sub-interface (unit) configured under a physical interface in Junos that carries protocol-family addresses and VLAN tags.
MPLSMultiprotocol Label Switching
A data-forwarding technique that uses short fixed-length labels to direct packets along predetermined paths, reducing reliance on IP routing lookups.
NTPNetwork Time Protocol
A protocol defined in RFC 5905 used to synchronize the clocks of network devices to a reference time source.
OSPFOpen Shortest Path First
A link-state interior gateway routing protocol standardized in RFC 2328 that uses the SPF algorithm to compute shortest paths within an autonomous system.
PFEPacket Forwarding Engine
The data-plane component of a Junos device that performs high-speed packet forwarding based on the FIB downloaded from the Routing Engine.
policy
A routing policy in Junos that controls which routes are accepted into or advertised out of the routing table using match conditions and actions.
RERouting Engine
The control-plane processor on a Junos device responsible for running routing protocols, maintaining the routing table, and managing system software.
RIBRouting Information Base
The routing table maintained by the Routing Engine that stores all routes learned from routing protocols, static configuration, and direct interfaces.
SNMPSimple Network Management Protocol
A network management protocol used to collect statistics and configuration data from network devices using a manager-agent model.
SSHSecure Shell
A cryptographic network protocol used to establish secure remote CLI sessions to Junos devices over untrusted networks.
static route
A manually configured route in the Junos routing table that does not change unless an administrator modifies it, used for simple or fixed-path routing.
syslogSystem Log
A facility in Junos for recording system events, errors, and informational messages to local files or remote syslog servers.
traceroute
A Junos operational-mode diagnostic command that discovers the Layer 3 path to a destination by sending probes with incrementing TTL values.
VLANVirtual Local Area Network
A logical segmentation of a Layer 2 network using IEEE 802.1Q tagging to separate broadcast domains on shared physical infrastructure.