Juniper Updated JN0-363 Exam Questions and Answers by chaya

In MPLS (Multiprotocol Label Switching) networks, routers use label switching to forward packets. The first router at the edge of the MPLS network (R1) will perform a lookup in the mpls.0 table to determine the label to attach to the packet as it enters the MPLS network. This label informs the next routers in the MPLS network (like R2) on how to forward the packet. Internal MPLS routers, like R2, also perform lookups in their mpls.0 table to determine how to switch the packet toward its destination (label swapping). The inet.3 table is used for resolving next-hop information for labeled routes, but it's the mpls.0 table that is used for label switching decisions.

References:

• Juniper Networks documentation on MPLS: MPLS Applications User Guide for Routing Devices

In VRRP (Virtual Router Redundancy Protocol), the router with the highest priority is elected as the master (primary) router. In the exhibit, routers R1 and R4 are both configured with a VRRP priority of 90. Since R2 and R3 have default priorities (which are lower than 90), they will not be elected over R1 or R4. Between R1 and R4, if all else is equal, the router with the numerically higher IP address becomes the master. However, if not enough information is provided to determine which of R1 or R4 has the higher IP address, the answer would be the one explicitly mentioned with the highest priority.

References:

• Juniper Networks documentation on VRRP: VRRP Overview

metric—Metric value. Range: 1 through 63, or 1 through 16,777,215 (if you have configured wide metrics) Default: 10 (for all interfaces except lo0), 0 (for the lo0 interface)

https://www.catchpoint.com/bgp-monitoring/bgp-attributes

BGP Attribute Categories

There are four categories of BGP attributes:

Well-known mandatory:Recognized by all BGP peers, passed to all peers, and present in all Update messages. Well-known mandatory attributes include:- Next-hop- Origin- AS PATH

Well-known discretionary:Recognized by all routers, passed to all peers, and optionally included in the Update message. Well-known discretionary attributes include:- Local Preference- Atomic Aggregate

Optional transitive:Possibly recognized by BGP routers and passed to BGP peers. Optional transitive attributes are marked as partial when not recognized. Optional transitive attributes include:- Aggregator- Community

Optional non-transitive:Possibly recognized by BGP routers but not passed to peers. Optional non-transitive attributes include:- Multi-exit discriminator (MED)- Originator ID- Cluster-ID

The three well-known mandatory BGP attributes that must be present in every BGP update message are:

• Next Hop: Indicates the next hop IP address to reach the advertising BGP peer.
• Origin: Indicates how the route was originated, whether it was via IGP, EGP, or incomplete.
• AS Path: Lists the autonomous systems that the update has traversed.

References

• Juniper Networks Technical Documentation on BGP Attributes