Specifications

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3. JUNOS SOFTWARE SPECIFICATIONS
3.1 JUNOS Software Architecture
All JUNOS routing protocols were developed in-house. JUNOS has been running
production traffic in the largest ISP networks in the Internet since the first half of
1998. JUNOS implements “bug-for-bug” compatibility modes ensuring correct
operation with leading vendor’s routers. Juniper’s software team has extensive
experience implementing most widely used routing software in the Internet.
The JUNOS software currently supports the following main features:
§ BGP4, with confederations, route reflectors, communities, route flap
damping, TCP MD5 authentication, multiprotocol extensions, capability
negotiation
§ OSPF, IS-IS, RIP v2 interior gateway protocols
§ Flexible policy software for filtering and modifying route advertisements
§ MPLS with RSVP extensions and LDP for traffic engineering
§ DVMRP, PIM-SM, PIM-DM, MSDP and IGMP for multicast
§ Configuration management features for enhanced usability
§ Secure remote access with SSH (USA version only)
The same JUNOS software runs both on the M40 and the M20.
JUNOS Internet Software Advantages
Features Benefits
Industrial strength BGP4, IS-IS, OSPF, and IP
multicast implementations
§
Efficient and scalable traffic routing through the
infrastructure
JUNOS policy definition language
§ Supports flexible and scalab
le peering relationships
§ Supports tens of thousands of routes
Applications run in protected memory
§
Ensures system reliability by protecting against
system crashes
Modularized
§
Enables you to start a specific module without
rebooting the entire operating system
§
Protects against complete operating system failures
§ Increases scalability
User-friendly CLI
§ Multiple user access levels
§ Configuration change control
§ Support for ASCII files
§ Ability to return to previous configurations
Purposely designed for service providers
§ No monolithic code base
§ One build for all applications and all platforms
3.1.1 JUNOS Architecture
The software consists of a series of system processes that handle the router’s
management processes, routing protocols, and control functions. The JUNOS
kernel, which is responsible for scheduling and device control, underlie and
support these processes.
The JUNOS architecture is a multi-module design, with each process running in
protected memory to guard against system crashes and to ensure runaway
applications do not corrupt each other. This modular design makes it significantly
easier to restart or upgrade a specific module since you do not have to reboot the
entire chassis. Introducing services is highly reliable since the failure of one
module does not adversely impact the entire operating system. Between these
independent modules, there are clean, well-defined interfaces that provide
interprocess communication, resulting in a highly reliable software architecture.
JUNOS software resides in the Routing Engine, which runs an Intel-based PCI
platform. The Routing Engine has a dedicated 100-Mbps internal connection to
the Packet Forwarding Engine, which is responsible for packet flow through the
router.
Operating System
Operating System
Operating System
Operating System
ProtocolsProtocols
Interface MgmtInterface Mgmt
Chassis MgmtChassis Mgmt
SNMPSNMP
SecuritySecurity