Which statement is correct about member interfaces when creating a LAG?
B
Explanation:
When creating a LAG (Link Aggregation Group) in Junos, the duplex settings and link speed must be
the same across all member interfaces.
Step-by-Step Breakdown:
LAG Overview:
A LAG combines multiple physical interfaces into a single logical interface to increase bandwidth and
provide redundancy. All member links must act as a single cohesive unit.
Interface Requirements:
Duplex: All member interfaces must operate in the same duplex mode (either full-duplex or half-
duplex). Mismatched duplex settings can cause performance issues, packet drops, or interface errors.
Link Speed: All interfaces in the LAG must have the same link speed (e.g., all interfaces must be 1
Gbps or 10 Gbps). Mismatched speeds would prevent the interfaces from functioning correctly
within the LAG.
Configuration and Validation: Ensure that all member interfaces have identical settings before adding
them to the LAG. These settings can be checked using the show interfaces command, and the LAG
can be configured using:
set interfaces ae0 aggregated-ether-options link-speed 10g
set interfaces ge-0/0/1 ether-options 802.3ad ae0
Juniper Reference:
LAG Configuration: Duplex and link speed must be consistent across member interfaces to ensure
proper LAG operation in Juniper devices.
Which three actions are required to implement filter-based forwarding? (Choose three.)
A, C, E
Explanation:
Filter-Based Forwarding (FBF) in Junos OS allows traffic to be routed based on specific criteria such as
source address, rather than just the destination address. This is useful in scenarios like policy routing
or providing multiple paths for different types of traffic.
Step-by-Step Breakdown:
Instance-Type Forwarding:
You must create an instance-type forwarding routing instance. This routing instance allows for
different routing tables based on the incoming packet filter.
Command:
set routing-instances FBF-instance instance-type forwarding
Match Filter:
You need to create a filter to match the traffic that will be forwarded according to your custom
routing policy. This filter is applied to an interface to determine which traffic will use the custom
forwarding instance.
Command Example:
set firewall family inet filter FBF-filter term 1 from source-address <address>
set firewall family inet filter FBF-filter term 1 then routing-instance FBF-instance
RIB Group:
A RIB (Routing Information Base) group is necessary to share routes between the primary routing
table and the custom routing instance. This allows FBF traffic to use the routing information from
other routing tables.
Command Example:
set routing-options rib-groups FBF-group import-rib inet.0
set routing-instances FBF-instance routing-options rib-group FBF-group
Juniper Reference:
FBF Configuration: Filter-based forwarding requires these specific steps to redirect traffic to a custom
routing table based on filter criteria.
Which signaling protocol is used for EVPN?
D
Explanation:
EVPN (Ethernet Virtual Private Network) is a standard protocol used for building Layer 2 and Layer 3
VPNs over an IP or MPLS network. The signaling protocol used for EVPN is BGP (Border Gateway
Protocol).
Step-by-Step Breakdown:
BGP as the EVPN Signaling Protocol:
EVPN uses BGP to exchange MAC address reachability information between routers (PE devices).
This enables devices to learn which MAC addresses are reachable through which PE devices,
facilitating Layer 2 forwarding across an IP or MPLS core.
BGP Extensions for EVPN:
BGP is extended with new address families (e.g., EVPN NLRI) to carry both MAC and IP address
information, allowing for scalable and efficient multi-tenant network solutions.
Juniper Reference:
Junos EVPN Configuration: Juniper uses BGP as the control plane for EVPN to exchange MAC and IP
route information between different data center devices.
Which operation mode command will display the mapping between the VLAN ID and ports on a
switch?
D
Explanation:
To display the mapping between VLAN IDs and ports on a Juniper switch, the show vlans command is
used.
Step-by-Step Breakdown:
VLAN Information:
The show vlans command displays detailed information about VLAN configurations, including the
VLAN ID, associated interfaces (ports), and VLAN membership.
Command Example:
show vlans
This command will provide an output listing each VLAN, its ID, and the interfaces associated with the
VLAN, enabling network engineers to quickly verify VLAN to port mappings.
Juniper Reference:
VLAN Verification: Use the show vlans command to verify which VLANs are configured on the switch
and the ports that are members of those VLANs.
Within your router, you want to verify that you are learning routes from a remote BGP peer at IP
address 10.10.100.1. Which command would satisfy the requirement?
A
Explanation:
To verify that your router is learning routes from a remote BGP peer at a specific IP address (e.g.,
10.10.100.1), the correct command to use is show route receive-protocol bgp.
Step-by-Step Breakdown:
BGP Route Learning:
The show route receive-protocol bgp command displays the routes that have been received from a
specified BGP peer. This helps in confirming that the remote peer is sending routes correctly and that
your router is receiving them.
Command Example:
show route receive-protocol bgp 10.10.100.1
This will show all routes that have been received from the BGP peer with IP address 10.10.100.1.
Juniper Reference:
BGP Route Verification: Use this command to troubleshoot and verify that routes from a specific BGP
peer are being received.
When a MAC limiting violation occurs, the switch performs which two actions by default? (Choose
two.)
C, D
Explanation:
When a MAC limiting violation occurs on a Juniper switch, the switch will perform the following
actions by default:
Step-by-Step Breakdown:
Port Disabled:
When the number of MAC addresses on an interface exceeds the configured limit, the port is
automatically disabled to prevent further violations. This is a protective mechanism to prevent MAC
address flooding.
Packet Dropped:
Additionally, packets from the violating MAC address are dropped to prevent any further
communication from that address. This ensures that only valid MAC addresses are allowed to
communicate through the interface.
Example Configuration:
set ethernet-switching-options secure-access-port interface <interface-name> mac-limit 5
If more than five MAC addresses are learned, the port is disabled, and excess packets are dropped.
Juniper Reference:
MAC Limiting: When the switch detects a MAC limiting violation, it disables the port and drops
further packets from the violating MAC addresses to maintain network security.
What information in the Ethernet header is used to populate the bridging table?
B
Explanation:
The source MAC address in the Ethernet header is used to populate the bridging table (also called
the MAC address table) on a switch. When a frame arrives at a switch, the switch examines the
source MAC address and records it along with the ingress port in its MAC address table.
Step-by-Step Breakdown:
Learning Process:
When an Ethernet frame arrives on a switch port, the switch looks at the source MAC address and
adds this MAC address to the MAC table along with the port it was received on. This process is called
MAC learning.
Purpose:
The switch uses this information to determine the correct port to send frames destined for that MAC
address in future transmissions, thus ensuring efficient Layer 2 forwarding.
Juniper Reference:
Ethernet Switching: Juniper switches use source MAC addresses to build and maintain the MAC
address table, which is essential for Layer 2 switching.
You are configuring an aggregate route. In this scenario, which two statements are correct? (Choose
two.)
B, C
Explanation:
When configuring an aggregate route, you have options for how to handle traffic that matches the
route but does not match any more specific route in the routing table. Two actions can be taken:
discard and reject.
Step-by-Step Breakdown:
Discard:
The discard option will silently drop packets that match the aggregate route. No notification is sent to
the sender, and the packet is simply dropped.
Reject:
The reject option will drop the packet and also send an ICMP Destination Unreachable message back
to the sender. This informs the sender that the packet could not be delivered because there is no
specific route available.
Juniper Reference:
Aggregate Routes: The reject and discard next-hop options provide different levels of feedback when
packets cannot be routed, and they can be used to control how unreachable destinations are
handled.
What are two requirements for an IP fabric? (Choose two.)
A, B
Explanation:
An IP fabric is a network architecture commonly used in data centers to provide scalable, high-
throughput connectivity using a spine-leaf topology.
Step-by-Step Breakdown:
Layer 3 Routing Protocol:
An IP fabric relies on a Layer 3 routing protocol, typically BGP or OSPF, to provide routing between
the leaf and spine switches. This ensures efficient traffic forwarding across the network.
Single Connection Between Spine and Leaf:
In an IP fabric, each leaf switch connects to every spine switch with a single connection. This ensures
that traffic between any two leaf switches can travel through the spine layer in just two hops.
Juniper Reference:
Spine-Leaf Design: Juniper’s IP fabric implementations are designed for scalability and low-latency
routing, often using protocols like BGP for Layer 3 control.
What is the main purpose of Bidirectional Forwarding Detection (BFD)?
A
Explanation:
Bidirectional Forwarding Detection (BFD) is a network protocol used to detect failures in the network
path between two devices quickly.
Step-by-Step Breakdown:
Path Failure Detection:
BFD provides a low-overhead mechanism for detecting failures in forwarding paths across Layer 3
networks. It is much faster than traditional routing protocol timers and can detect failures within
milliseconds.
BFD in Routing:
BFD can be integrated with routing protocols like OSPF, BGP, or IS-IS to trigger a faster convergence
when a network path goes down.
Juniper Reference:
BFD Configuration: Juniper devices use BFD to monitor network paths and ensure fast failure
detection, enhancing network resilience.