Free Service Provider Routing and Switching - Specialist (JNCIS-SP) Practice Questions

In Junos OS for switching platforms, an interface is configured for Layer 2 bridging under thefamily ethernet-switchinghierarchy. The way an interface handles VLAN traffic depends on its port mode:accessortrunk.

According to Juniper Networks technical documentation, when an interface is configured simply with members , it defaults to anaccess port. In an access port configuration:

The port is a member of only a single VLAN.

The portreceives and sends untagged traffic (Option C). Any untagged frame arriving at this interface is implicitly associated with the configured VLAN member.

The interface does not expect or process 802.1Q tags in incoming frames.

In the exhibit, interface xe-0/0/4 has members 10;. In Junos, the members statement can reference either aVLAN nameor aVLAN ID. However, when the configuration is shown as members 10; without further context of the specific ID mapping, the most precise interpretation of the CLI output provided is thatthe interface is a member of the VLAN named 10 (Option D). While "10" could be the numerical ID, Junos primarily maps members by their defined administrative name.

Why other options are incorrect:

Option A:Access ports do not receive tagged traffic; only trunk ports (which require the port-mode trunk and vlan members [ ... ] statements) are designed to process tagged frames.

Option B:While the VLAN named 10likelyhas a VLAN ID of 10, the exhibit does not explicitly confirm the ID mapping. In Junos, a VLAN named "10" could technically have a different tag ID (e.g., VLAN "Office" with ID 10). Option D is the more accurate direct reading of the displayed member configuration.

When implementingMultiprotocol BGP (MP-BGP)for IPv6, several architectural constants remain consistent with the original BGP design, while others have evolved to accommodate larger network scales.

Router ID (Option C):

A critical point in Juniper's Service Provider documentation is that theBGP Router IDremains a32-bit value, even when the protocol is carrying 128-bit IPv6 prefixes. The Router ID is typically represented in dotted-quad notation (e.g., 192.168.1.1). In an IPv6-only environment, a Juniper router cannot automatically derive this ID from an interface address, so it must be manually defined under [edit routing-options]. This 32-bit ID is essential for BGP tie-breaking and loop prevention within the AS.

Autonomous System Number (Option D):

TheAutonomous System Number (ASN)was originally a 16-bit value (0 to 65535). However, to address the exhaustion of available ASNs, the standard was extended to32-bit ASNs(documented in RFC 6793). In Junos OS, you can configure BGP using either the older 16-bit format or the newer 32-bit format (often represented in "asplain" or "asdot" notation). While the question mentions a 64-bit value, there is currently no standard for a 64-bit ASN in BGP; the transition from 16-bit to 32-bit satisfies current global scalability needs. Therefore, Option D is the most accurate within the context of current networking standards, as it acknowledges the coexistence of different ASN lengths.