Configuring Routing Protocols

After you have set up the interfaces on which IP traffic flows, you can configure the following routing protocols:

• IP Multicast - IP multicasting allows a device to send packets to a group of hosts, rather than to a list of individual hosts. Routers use multicast routing algorithms to determine the best route and transmit datagrams throughout the network. See ERX Routing Protocols Configuration Guide, Vol. 1, Chapter 4, Configuring IP Multicasting, for information on how to configure IP Multicast.
• Open Shortest Path First (OSPF) - This interior gateway protocol (IGP) advertises the states of network links within an autonomous system. An autonomous system is a set of routers having a single routing policy running under a single technical administration. See ERX Routing Protocols Configuration Guide, Vol. 1, Chapter 8, Configuring OSPF, for information on how to configure OSPF.
• Integrated Intermediate System-to-Intermediate System (integrated IS-IS) - The integrated IS-IS protocol provides routing for IP networks and is an extension of the original IS-IS protocol, which provides routing for pure Open Systems Interconnection (OSI) environments. This link state protocol builds a complete and consistent picture of a network's topology by sharing link state information across network devices in a routing domain. A routing domain is a collection of contiguous networks that provide full connectivity to all end systems located within them. See ERX Routing Protocols Configuration Guide, Vol. 1, Chapter 9, Configuring IS-IS, for information on how to configure IS-IS.
• Border Gateway Protocol (BGP) - An external gateway protocol (EGP) that provides loop-free interdomain routing between autonomous systems. See ERX Routing Protocols Configuration Guide, Vol. 2, Chapter 1, Configuring BGP Routing, for information on how to configure BGP.
• Routing Information Protocol (RIP) - An IGP created for use in small, homogeneous networks. RIP uses distance-vector routing to route information through IP networks. See ERX Routing Protocols Configuration Guide, Vol. 1, Chapter 7, Configuring RIP, for information on how to configure RIP.
• Multiprotocol Label Switching (MPLS) - A hybrid protocol that integrates network layer routing with label switching to provide a layer 3 network with traffic management capability. Traffic engineering enables more effective use of network resources while maintaining high bandwidth and stability. MPLS enables service providers to offer their customers the best service available given the provider's resources. There are two fundamental aspects to MPLS:

• Label distribution - The set of actions MPLS performs to establish and maintain a label-switched path (LSP), also known as an MPLS tunnel.
• Data mapping - The process of getting data packets onto an established LSP.
  See ERX Routing Protocols Configuration Guide, Vol. 2, Chapter 2, Configuring MPLS, for information about configuring MPLS.

In addition, if you want to make configuration adjustments to IP, see ERX Routing Protocols Configuration Guide, Vol. 1, Chapter 2, Configuring IP, for details.