Which routing-instance type allows the sharing of interface routes and the support features used in source-based routing?
A.
virtual-router
B.
vrf
C.
forwarding
D.
multi-instance
Explanation:
Routing Policy vs. Policy Based Routing on JUNOSSummary:
Routing policy is the generic term for all the mechanisms under policy-options in JUNOS.
Policy Based Routing is usually and more accurately known within Juniper as Filter Based Forwarding.Solution:
* ForwardingUse this routing instance type for filter-based forwarding applications. For this instance type, there is no one-to-one mapping between an interface and a routing instance. All interfaces belong to the default instance inet.0
* Routing policy is the generic term for all the mechanisms under policy-options in JUNOS. These Routing Policy allows you to modify the routes that are advertised to or accepted from a neighbor while using any of the supported routing protocols. This is usually applied using the import / export statements in each of the protocols. It affects control plane, route updates, advertisements etc.
* Policy Based Routing (PBR) is Filter Based Forwarding. It is an approach where you override some of the fundamental rules of destination based routing and forward packets based on other characteristics of the incoming packets. This is achieved by writing firewall filters that match the relevant characteristics of the incoming packet (src ip, dst ip, src port, dst port, protocol, packet size, etc) and modify the next-hop based on that match. The packet is then forwarded to that next-hop rather than using the next-hop associated with the destination ip address alone. It affects the data plane L3 forwarding function.Note: When searching the Technical Documentation for Policy Based Routing (PBR) configuration, search for: filter-based forwarding