Integrated Routing and Bridging (IRB) JN0-281 Practice Questions (Page 1)

Questions 1–5

1. 1foundation · easy

   A switch has an IRB interface configured for VLAN 200, but hosts cannot reach the gateway. What is a likely cause?

   • AThe VLAN has too many member ports.
   • BThe switch is not running OSPF.
   • CThe IRB interface is not associated with the VLAN via the 'l3-interface' statement.
   • DThe IRB interface has a /32 mask configured.
   Reveal Solution Discussion Select an answer first
2. 2foundation · easy

   What is the primary purpose of an Integrated Routing and Bridging (IRB) interface in a Juniper data center switch?

   • ATo create a Layer 2 loop-free topology by blocking redundant paths between switches.
   • BTo provide a dedicated management interface for out-of-band access to the switch.
   • CTo connect two separate physical switches into a single logical switch for management purposes.
   • DTo provide a Layer 3 routing interface for a VLAN, allowing the switch to route traffic between VLANs.
   Reveal Solution Discussion Select an answer first
4. 3expert · hard

   A data center architect is deciding between using IRB on access switches versus using a centralized routing model with IRB on core switches. The network has 50 VLANs, and the team wants to minimize the number of routing devices to manage. Which approach best meets this requirement?

   • AUse a mix of IRB on access and core switches for different VLANs.
   • BDo not use IRB; use a separate router for each VLAN.
   • CConfigure IRB on each access switch for the VLANs present on that switch.
   • DConfigure IRB on the core switches for all 50 VLANs.
   Reveal Solution Discussion Select an answer first
5. 4foundation · easy

   When a host in VLAN 10 sends a packet to a host in VLAN 20 on the same switch, what does the switch do with the packet?

   • AIt bridges the packet directly from VLAN 10 to VLAN 20 without any Layer 3 processing.
   • BIt floods the packet to all ports in both VLANs.
   • CIt drops the packet because switches cannot route between VLANs.
   • DIt routes the packet from the IRB interface of VLAN 10 to the IRB interface of VLAN 20.
   Reveal Solution Discussion Select an answer first
6. 5application · medium

   A Juniper switch has IRB interfaces for VLAN 10 (192.168.10.1/24) and VLAN 20 (192.168.20.1/24). A host on VLAN 10 sends a packet to a host on VLAN 20. What does the switch do with the packet after receiving it on the access port?

   • AIt performs a Layer 3 lookup and routes the packet out the IRB interface for VLAN 20.
   • BIt drops the packet because IRB interfaces cannot route between VLANs.
   • CIt sends the packet to the default gateway of VLAN 10, which is the IRB interface.
   • DIt forwards the packet out all ports in VLAN 20 after a Layer 2 lookup.
   Reveal Solution Discussion Select an answer first