JUNOS Internet Software Overview
by a VPN customer with connections to several various ISPs, or different
connections to the same ISP in various geographic regions.
Carrier-of-Carrier VPNs—Carrier-of-carrier VPNs allowa VPN service provider
to supply VPN service to a customer who is also a service provider. The latte r
service providersupplies Internet or VPN service to an end customer.
Interface Process
The JUNOS interface processmanages the physical interface devices and logical
interfaces on the router. It implements the JUNOS command-line interface
(CLI) commands and configurationstatements that you use to specify interface
properties such as location (FPClocation in the FPC card cage and PIC location
on an FPC), the interface type (such as SONET/SDH or ATM), encapsulation,
and interface-specific properties. You can configureboth interfaces that are
currently active and interfacesthat might be installed later.
The JUNOS interface process communicates with the interface process in the
PacketForwarding Engine through the JUNOS kernel, enabling the JUNOS Internet
software to track the status and condition of router interfaces.
Chassis Process
The JUNOS chassis processallows you to configure and control the properties of
the router,including conditions that trigger alarms and clock sources. The chassis
process communicates directly with a chassi s process in the JUNOS kernel.
SNMP and MIB II Processes
The JUNOS Internet software supportsthe Simple Network Management
Protocol (SNMP), versions 1, 2, and 3, which providesa mechanism for
monitoring the state of the router. This software is controlledby the JUNOS
SNMP and Management Information Base (MIB) IIprocesses, which consist
of an SNMP master agent and a MIB II agent.
Management Process
The management process startsall the other JUNOS software processes and the
CLI when the router boots. It monitors the running JUNOS processesand makes
all reasonable attempts to restartany process that terminates.
Routing Engine Kernel
The Routing Engine kernelprovides the underlying infrastructure for all JUNOS
software processes. It also provides the link be tween the routing tables maintained
by the routing protocol pro cess and the forwarding table main tained by the Routing
Engine. Additionally,it coordinates communication with the Packet Forwarding
Engine, which primarilyinvolves synchronizing the Packet ForwardingEngine’s
forwarding table with th e master forwarding table m aintained by the Routin g Engine.
Routing Engine Software Components 49