Junos OS Routing Processes
Junos OS consists of multiple processes that run on different platforms and have unique functions. The separation of functions provides operational stability, because each process accesses its own protected memory space. This section provides a brief overview of Junos OS routing-specific processes.
As an example, Table 1 describes the processes that run on MX Series 5G Universal Routing Platforms.
Table 1: Junos OS Processes on MX Series Platform
Clksync process (RE)
Defines the operation of synchronous Ethernet and Precision Time Protocol (PTP) on a Juniper Networks MX Series router. The operation includes communication with the Packet Forwarding Engine (clock-sync module) to program and process clock events from the EEC clock.
Operates the PTP stack, exchanges packets, and handles the configuration changes for the modular MX Series (MX80).
Controls the configuration and monitoring of the overall operation of the PTP functionality for chassis-based MX Series platforms (MX240, MX480, and so on).
Clock-sync process (PFE)
Programs and monitors the modular interface card (MIC), the CPLD, and the EEC clock. Peer of the clksyncd process module.
Captures all PTP and Synchronous Ethernet statistics on the Packet Forwarding Engine and provides them to the Routing Engine.
Interchassis communication process
Exchanges proprietary Junos OS messages between two Juniper Networks MX Series routers that take part in a multichassis link aggregation group (LAG).
Statistics agent process
Acts as a relay process to collect interface statistics for all software development kit (SDK) applications.
Interacts with the pfed process to collect the logical interface statistics for SDK applications.
Table 2 lists other processes that are common across Junos OS routing platforms.
Table 2: Junos OS Routing-Specific Processes
Adaptive services process
Alarm control process
Configures the system alarm.
Access Node Control Protocol (ANCP) process
Works with a special Internet Group Management Protocol (IGMP) session to collect outgoing interface mapping events in a scalable manner.
Application identification process
Identifies an application using intrusion detection and prevention (IDP) to allow or deny traffic based on applications running on standard or nonstandard ports.
RADIUS accounting process
Gathers statistical data that can be used for general network monitoring, analyzing, and tracking usage patterns, for billing a user based upon the amount of time or type of services accessed.
Configures interfaces automatically.
Captive portal content delivery process
Specifies the location to which a subscriber's initial Internet browser session is redirected, enabling initial provisioning and service selection for the subscriber.
Universal Edge Layer 2 Tunneling Protocol process
(M10, M10i, M7i, and MX Series routers only) Establishes L2TP tunnels and Point-to-Point Protocol (PPP) sessions through L2TP tunnels.
Ethernet OAM connectivity fault management process
Monitors the physical link between two switches.
Chassis control process
Manages the chassis.
Class of service process
Controls the network device’sCoS configuration.
Ethernet clock synchronization process
Uses Synchronous Ethernet (SyncE) for external clock synchronization .
Craft interface I/O control process
Controls the I/O of the craft interface.
Database replication process
(EX Series switches and MX Series routers only) Manages the replication of updates from the master to the slave in the database management system.
Datapath trace process
Traces the path taken by the packet through the network.
Dynamic Host Configuration Protocol process
(EX Series switches and MX Series routers only) Enables a DHCP server to allocate network IP addresses and deliver configuration settings to client hosts without user intervention.
Implements the Diameter protocol which uses the Transmission Control Protocol (TCP) and Stream Control Transmission Protocol (SCTP) instead of User Datagram Protocol (UDP), for monitoring the network.
Disk monitoring process
Checks the health of the hard drive on the Routing Engine.
Dynamic flow capture (DFC) process
Controls the DFC configurations on Monitoring Services III PICs.
ECC parity errors logging process
Logs the ECC parity errors into the memory on the Routing Engine.
Connectivity fault management (CFM) process
Provides IEEE 802.1ag OAM CFM database information for CFM maintenance association end points (MEPs) in a CFM session.
Ethernet OAM Link-Fault-Management process
(EX Series switches and MX Series routers only) Provides the OAM link fault management (LFM) information for Ethernet interfaces.
Event processing process
Configures the application to handle all generated events.
Manages the firewall configuration and enables accepting or rejecting packets that are transiting an interface on a device.
General authentication process
(EX Series switches and MX Series routers only) Manages general authentication of a user.
Inter-Chassis Communication Protocol (ICCP) process
IDP policy process
Enables various attack detection and prevention techniques on traffic traversing the network.
Integrated Local Management Interface process
Provides bidirectional exchange of management information between two Asynchronous Transfer Mode (ATM) interfaces across a physical connection.
Configures the IP multicast family.
Initializes the USB modem.
Interface control process
Controls the router's or switch’s physical interface devices and logical interfaces.
Kernel replication process
Replicates the state of the backup Routing Engine when graceful Routing Engine switchover (GRES) is configured.
Layer 2 address flooding and learning process
Enables a network device to:
Layer 2 Control Protocol process
Enables features such as Layer 2 protocol tunneling and nonstop bridging.
Link Aggregation Control Protocol process
Link management process
Manages traffic engineering links.
Local policy decision function process
Regulates the collection of statistics related to applications and application groups and tracking of information about dynamic subscribers and static interfaces.
Logical system multiplexer process
Manages multiple instances of the routing protocols process (rpd) on a machine running logical routers.
MAC validation process
Configures MAC address validation that enables a network device to validate if received packets contain a trusted IP source and an Ethernet MAC source address.
Management Information Base II process
Provides the device's MIB II agent.
Mobile IP process
Configures Junos OS Mobile IP features.
NFS mount requests process
(Some EX Series switches and MX Series routers only) Completes internal NFS mount requests for MS-PIC and MS-MPC.
MPLS Periodic Traceroute process
Configures multiservice edge routers.
Multicast Snooping process
(EX Series switches and MX Series routers only) Makes Layer 3 information, such as the MAC addresses of members of a multicast group, known to Layer 2 devices, such as VLAN switches.
DNS server process
Enables a device to resolve hostnames into addresses.
Bidirectional Forwarding Detection (BFD) process
Displays the process that specifies the maximum length of time that the device waits for its neighbor to re-establish an LDP session.
Remote NFS server process
Provides remote file access for applications that need NFS-based transport.
Network time process
Provides the mechanisms to synchronize time and coordinate time distribution in a large, diverse network.
Packet-triggered dynamic subscribers and policy control (PTCP) process
Enables the application of policies to dynamic subscribers that are controlled by a subscriber termination device.
Peer selection service process
Enables peer selection.
Periodic packet management process
Processes a variety of time-sensitive periodic tasks so that other processes can more optimally direct their resources.
Packet Forwarding Engine process
Gathers and reports Packet Forwarding Engine statistics.
Packet gateway service process
Pragmatic General Multicast process
Enables a reliable transport layer for multicast applications.
PIC services logging process
fsad (the file system access daemon)
Enables PICs to send special logging information to the Routing Engine for archiving on the hard drive.
Point-to-Point Protocol (PPP) process
Enables transporting IP traffic across point-to-point links.
Universal edge PPP process
Enables transporting IP traffic across universal edge routers.
Point-to-Point Protocol over Ethernet process
Allows users to connect to a network of hosts over a bridge or access concentrator.
Process health monitor process
Extends the SNMP RMON alarm infrastructure to provide predefined monitoring for a selected set of object instances (such as file system usage, CPU usage, and memory usage) and dynamic object instances (such as Junos OS processes).
Note: The process health monitor process is enabled by default on the Routing Engines of MX Series routers, even when no service interfaces are configured. To disable this process, include the disable statement at the [edit system processes process-monitor] hierarchy level.
Redundancy interface management process
Serves as an active or backup process of an application server and can be configured to process traffic for more than one logical application server.
Remote operations process
Resource cleanup process
Enables cleaning of resources by entities other than the application itself.
Directs forwarding on the basis of routing tables, which maintain a record of the routes to various network destinations.
Traffic sampling control process
Performs packet sampling based on particular input interfaces and various fields in the packet header.
Session Border Control (SBC) configuration process
Configures the session border controller functionality that enables delivery of voice, video, and other multimedia services with assured quality and security.
SDK service process
Runs on the Routing Engine and enables communication between the SDK application and Junos OS. Although the SDK service process is present on the router, it is turned off by default.
Secure Neighbor Discovery (SND) protocol process
(EX Series switches and MX Series routers only) Provides support for protecting NDP messages.
Service Deployment System (SDX) process
Enables Junos OS to work with the Session and Resource Control (SRC) software.
Simple Network Management Protocol (SNMP) process
Enables the monitoring of network devices from a central location, and provides the device’s SNMP master agent.
SONET Automatic Protection Switching (APS) process
Monitors any SONET interface that participates in APS.
Static subscribers process
Associates subscribers with statically configured interfaces, and provides dynamic service activation and activation for these subscribers.
Tunnel OAM process
Enables the Operations, Administration, and Maintenance of Layer 2 tunneled networks.
Virtual Router Redundancy Protocol (VRRP) process
(EX Series switches and MX Series routers only) Enables hosts on a LAN to make use of redundant routing platforms on that LAN without requiring more than the static configuration of a single default route on the hosts.
Watchdog timer process
Enables the watchdog timer when Junos OS encounters a problem.