JN0-650: Enterprise Routing and Switching, Professional (JNCIP-ENT)Demo

An EVPN-VXLAN configuration on QFX uses encapsulation vxlan under the protocols evpn hierarchy. EVPN route exchange is enabled in BGP through the EVPN signaling address family, family evpn signaling. VPLS signaling does not provide EVPN control-plane signaling, and loopback reachability does not mandate BGP as its advertisement protocol.

The multipath statement in the ext-peers BGP group enables Junos to install multiple equal BGP paths rather than only one best path. Because both external peers belong to that group, eligible equal routes learned from each peer can be active simultaneously.

An OSPF interface priority of 0 makes the routing device ineligible to become the designated router. Because both devices have priority 0, neither can become DR or BDR; routers that are neither DR nor BDR on a broadcast segment maintain a 2-Way neighbor relationship rather than forming a full adjacency with one another. Juniper: Configuring OSPF Areas

An EVPN NLRI prefixed with 1: is a Type 1 Ethernet Auto-Discovery route. The nonzero Ethernet Segment Identifier indicates an Ethernet segment for a multihomed attachment; single-homed attachments use an all-zero ESI. Understanding EVPN Pure Type 5 Routes | Junos OS

The Junos accept-remote-nexthop statement allows a single-hop EBGP peer to accept a remote next hop that does not share a common subnet with the peer, overriding the default behavior that discards such routes.

OSPF database protection configures a maximum number of nonself-generated LSAs—LSAs advertised by routers other than the local router—in an OSPF instance. After the configured ignore-count threshold leads to the isolate state, the database remains isolated until the clear ospf database-protection command is issued.

PIM BSR dynamically distributes the group-to-RP mapping to all routers in a PIM sparse-mode domain. Configuring only a local RP does not provide that mapping to non-RP routers. BSR is the standards-based RP-discovery mechanism; MSDP addresses interdomain source discovery, while Auto-RP is not a standard protocol. Juniper: Configuring PIM Bootstrap Router

On EX Series switches, CoS policers meter traffic against configured bandwidth and burst limits using a token-bucket algorithm. This enforces an average bandwidth limit while allowing bursts up to the configured maximum.

BGP uses LOCAL_PREF within an autonomous system to select an outbound path, and the route with the higher preference is selected. Setting ISP A’s learned route above the default value of 100, or setting ISP B’s learned route below 100 while ISP A remains at 100, makes the ISP A path preferred throughout AS 65512.

Weighted tail drop (WTD) drops packets from the tail of a queue after the configured fill level is reached. Weighted random early detection (WRED) randomly and progressively drops packets during congestion according to the configured drop probability and packet loss priority (PLP).

OSPF is an interior gateway protocol that exchanges routing information within a single autonomous system and uses hello packets to establish and maintain neighbor relationships. It uses link-state information and the shortest-path-first algorithm.

EVPN Route Type 1 (Ethernet Auto-Discovery) and Route Type 4 (Ethernet Segment) carry the Ethernet Segment Identifier (ESI) for Ethernet-segment discovery and multihoming functions without being MAC advertisement routes. Route Type 2 is the MAC/IP Advertisement route.

The inet.2 table provides unicast routes for multicast reverse-path-forwarding (RPF) lookups, allowing multicast routing to use a topology independent of normal unicast forwarding. PIM uses inet.0 for RPF checks by default. inet.1 is the IPv4 multicast forwarding cache, not the direct route table for MP-BGP or IS-IS multicast routes; OSPFv3 uses IPv6 routing tables rather than IPv4 inet.2.

In Junos 802.1X, single-secure supplicant mode permits access for only one authenticated supplicant on the port and prevents additional devices from using it. The displayed single mode does not provide that same one-device access restriction.

In PIM sparse mode, an (S,G) entry identifies the multicast distribution tree for one specific source and group. An upstream “Prune to Source” state at the RP means the RP has pruned traffic for that specific (S,G) pair toward the source because it has no downstream interest in carrying that source’s traffic through the RP. The shared (*,G) state still represents the RP-based tree for the group and is independent of pruning one particular source. Cisco documents that (*,G) joins are sent toward the RP, whereas (S,G) joins are sent toward the source, and that a prune removes the relevant path from the distribution tree.

Multifield classifiers are configured with firewall filters and can match multiple packet-header fields. Behavior aggregate classifiers classify using fixed-length QoS markings, including DSCP and IEEE 802.1p, which makes them computationally more efficient than multifield classifiers. When both classifications apply, multifield classification can override behavior aggregate classification.

In Junos, a static MAC bypass list is configured on the switch and permits listed devices to access the LAN without 802.1X or MAC RADIUS authentication. The documented static MAC bypass configuration uses multiple-supplicant mode on the authenticator interface.

The 0.0.0.0/0 route from AS 64512 is rejected by the BGP import policy and is therefore retained as a hidden route. show route receive-protocol bgp <peer ip> hidden displays BGP routes received from that peer that are hidden by policy. Juniper: Basic BGP Routing Policies

Junos PIM SSM uses PIM sparse-mode functionality to establish the source-specific (S,G) tree, requiring PIM sparse mode on the relevant router interfaces. Because 239.100.100.100 falls outside the default 232.0.0.0/8 SSM range, it must be added as an additional SSM group under [edit routing-options multicast] with ssm-groups. SSM mapping is for IGMPv1/v2 hosts, whereas IGMPv3 receivers can signal source-specific membership directly.

R2's multicast RPF table resolves the source network 192.168.100.0/24 through interface ge-0/0/4.0, via neighbor 172.18.1.1. Traffic from source 192.168.100.10 arriving on that interface satisfies reverse-path forwarding. A multicast router that passes the RPF check forwards the packet through the eligible outgoing interfaces, excluding the incoming interface.

An eBGP session sourced from a local loopback and addressed to the remote loopback must use the remote loopback, 172.16.1.1, as its neighbor address and enable multihop. By default, eBGP assumes a directly connected peer and uses TTL 1. The static route supplies reachability to the remote loopback across the two physical links.

Junos hides BGP routes that cannot be used, including routes whose next hop cannot be resolved and routes whose AS path contains zero. A next hop that is unreachable therefore makes the route unusable, and AS 0 is an invalid AS-path condition that causes the route to be hidden.

EVPN-VXLAN edge-routed bridging places the Layer 3 gateway and IRB routing functions on the overlay-edge distribution/leaf switches. Corresponding IRB interfaces use shared anycast gateway IP addresses, allowing routing to occur locally at that distribution layer rather than centrally in the core.

VLAN rewrites use the swap operation to replace the incoming C-VLAN tag with an S-VLAN tag. Juniper documents this specific-interface mapping behavior as VLAN rewriting, also called VLAN translation.