JN0-1103 Design - Associate (JNCIA-Design) Questions and Answers

To support SRX chassis cluster design, two special interface types are required:

fab (fabric) interfaces for data plane synchronization and control interfaces for control plane communication between the nodes in the cluster.

The highlighted device connects to multiple servers and also connects upstream to spine switches. This placement and function identify it as a leaf node in a leaf-spine architecture, responsible for connecting endpoints (such as servers) into the fabric.

The Juniper Connected Security strategy aims to integrate security across the entire network by extending protection to routers, switches, and every point of connection, ensuring that security is enforced holistically - not just at the perimeter.

Juniper’s SASE (Secure Access Service Edge) solution combines Juniper Secure Edge, which delivers cloud-based security services, and Mist AI-Driven SD-WAN, which provides secure, intelligent WAN connectivity. Together, they support secure, seamless access across distributed environments.

The oversubscription ratio in an IP fabric is influenced by the number of spine nodes relative to the number of leaf nodes and their uplinks.

Removing spine nodes reduces available uplink bandwidth, increasing oversubscription.

Adding spine nodes increases available bandwidth between leafs and spines, decreasing the oversubscription ratio.

SD-WAN routes traffic, including security-sensitive data, across MPLS, VPNs, and Internet circuits using encryption and policy-based routing to ensure secure and efficient transmission, even over public networks.

EVPN-VXLAN is an overlay solution that extends Layer 2 network segments across a Layer 3 WAN. It enables seamless connectivity between remote sites or data centers while maintaining Layer 2 adjacency, making it ideal for distributed environments.

SD-WAN solutions can offer comparable security and privacy to traditional MPLS by using encryption and secure tunnels. They also support local breakout for Direct Internet Access (DIA) at remote sites, improving performance for cloud applications by avoiding backhaul to a central location.

Using a Virtual Chassis (VC) introduces a single point of failure in the management plane, as all member switches depend on a master for control. Replacing the VC with ESI-LAG (Ethernet Segment Identifier - Link Aggregation Group) allows dual-homed servers to connect to independent leaf switches while maintaining resiliency and independent management planes—thus eliminating the single point of failure.

PTX Series routers are purpose-built for the core network, offering ultra-high throughput, scalability, and low-latency forwarding ideal for service provider and large-scale data center cores.

cSRX and vSRX are the virtualized versions of the Juniper SRX Series firewalls designed for deployment in virtual environments. The cSRX is containerized, while the vSRX is a VM-based firewall, both supporting advanced security services in cloud or virtualized data centers.

When designing a WLAN, determining the number and location of access points is essential to ensure adequate coverage, capacity, and performance, while minimizing interference and ensuring seamless connectivity.

To ensure encryption of traffic between customer sites over a Layer 3 VPN, the most effective solution is IPsec with ESP (Encapsulating Security Payload). ESP provides both encryption and authentication, ensuring data confidentiality and integrity across the service provider network.

For a 120-meter (400-foot) connection between switches, multimode fiber is the most reliable and cost-effective option. It supports higher bandwidth and longer distances than UTP (which is limited to 100 meters) and is more stable and secure than a wireless solution.

SD-WAN enhances network security by using encryption for WAN traffic, ensuring data confidentiality over public or hybrid networks. It also supports zero-touch provisioning, which simplifies deployment by automating device configuration without manual intervention.