In an MPLS network, the types of routers include ingress routers (where the MPLS labels are first applied), egress routers (where MPLS labels are removed), and transit routers (which switch MPLS-labeled packets through the MPLS network). Peering routers andaggregation routers are not specific types of MPLS routers; they are general network terms.

References:

• Juniper Networks documentation on MPLS: MPLS Fundamentals

The exhibit shows an aggregate route configuration for the network172.21.0.0/22, which would summarize the specific networks172.21.0.0/24,172.21.1.0/24, and172.21.2.0/24. For an aggregate route to be active, it must have contributing routes in the routing table. If the route is hidden, it usually means there are no contributing routes that are active or the policy applied to the aggregate does not match any of the specific routes.Therefore, the first step in troubleshooting would be to verify that there are indeed active contributing routes for the aggregate to be valid.

References:

• Juniper documentation on routing policies and aggregates: Junos OS Routing Policies, Firewall Filters, and Traffic Policers User Guide

The AS path is a BGP attribute that lists the autonomous systems (AS) that routing information has passed through to get to a destination. It is used to detect and prevent routing loops by checking if the router's own AS number is in the path.

References:

• Juniper Networks documentation on BGP: BGP Attributes and Policy