Juniper Networks M10, M5 manual Routing Protocol Process, Routing Engine Software Components

Routing Engine Software Components

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SNMP and MIB II Processes on page 26

Management Process on page 27

Routing Engine Kernel on page 27

Routing Protocol Process

The JUNOS software routing protocol process controls the routing protocols that run on the router. The routing protocol process starts all configured routing protocols and handles all routing messages. It consolidates the routing information learned from all routing protocols into common routing tables. From this routing information, the routing protocol process determines the active routes to network destinations and installs these routes into the Routing Engine’s forwarding table. Finally, the routing protocol process implements the routing policies you specify, which determine how routing information is transferred between the routing protocols and the routing table.

This section discusses the following topics:

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IPv4 Routing Protocols on page 22

IPv6 Routing Protocols on page 24

Routing and Forwarding Tables on page 24

Routing Policy on page 25

For complete information about routing concepts, see the JUNOS Internet software configuration guides.

IPv4 Routing Protocols

The JUNOS Internet software implements full IP routing functionality, providing support for IP version 4 (IPv4). The routing protocols are fully interoperable with existing IP routing protocols and provide the scale and control necessary for the Internet core. The software provides support for the following routing and traffic engineering protocols:

•Unicast routing protocols

•BGP—Border Gateway Protocol, version 4, is an Exterior Gateway Protocol (EGP) that guarantees loop-free exchange of routing information between routing domains (also called autonomous systems). BGP, in conjunction with JUNOS routing policy, provides a system of administrative checks and balances that can be used to implement peering and transit agreements.

•ICMP—Internet Control Message Protocol router discovery is a method that hosts can use to discover the addresses of operational routers on a subnet.

•IS-IS—Intermediate System-to-Intermediate System is a link-state interior gateway protocol (IGP) for IP networks that uses the shortest-path-first algorithm (SPF algorithm, also called the Dijkstra algorithm) to determine routes.

22M5 and M10 Internet Routers Hardware Guide