Juniper Networks M10, M5 manual Routing Engine Functions, Routing Engine Architecture

Routing Engine Architecture

Figure 14: Routing Engine Architecture

JUNOS

software

System	Routing	Control
management	protocols	functions
processes

Kernel

Intel-based PCI platform

System processes

Operating system

1164

Routing Engine Functions

The Routing Engine handles all routing protocol processes, as well as the software processes that control the router’s interfaces, the chassis components, system management, and user access to the router. These routing and software processes run on top of a kernel that interacts with the Packet Forwarding Engine. For more information about the processes, see “Routing Engine Software Components” on page 21.

The Routing Engine includes the following functions and features:

•Processing of routing protocol packets—The Routing Engine handles all packets that concern routing protocols, freeing the Packet Forwarding Engine to handle only packets that represent Internet traffic.

•Software modularity—Because each software process is devoted to a different function and uses a separate process space, the failure of one process has little or no effect on the others.

•In-depth Internet functionality—Each routing protocol is implemented with a complete set of Internet features and provides full flexibility for advertising, filtering, and modifying routes. Routing policies are set according to route parameters (for example, prefix, prefix lengths, and Border Gateway Protocol [BGP] attributes).

•Scalability—The JUNOS routing tables have been designed to hold all the routes in current networks with ample capacity for expansion. Additionally, the JUNOS Internet software can efficiently support large numbers of interfaces and virtual circuits.

•Management interface—Different levels of system management tools are provided, including the JUNOS command-line interface (CLI), the JUNOScript application programming interface, the craft interface, and SNMP.

•Storage and change management—Configuration files, system images, and microcode can be held and maintained in primary and secondary storage systems, permitting local or remote upgrades.

32M5 and M10 Internet Routers Hardware Guide