JNCIS-ENT study plan
JNCIS-ENT · Give each week a clear focus.
8 weeks · About 7 hours per week
Spanning Tree & Layer 2 Switching or VLANs
Configure RSTP and VSTP on a multi-VLAN Junos switch topology and verify root bridge election with show spanning-tree bridge
Differentiate edge, no-root-port, and bpdu-block-on-edge port roles and predict their effect on convergence
Build an 802.1Q trunk and access-port lab and confirm VLAN membership with show vlans and show ethernet-switching table
Explain how MSTP regions map VLANs to instances and configure a two-instance region
Your checkpoint
A working 4-switch lab file set plus a one-page table mapping each STP port role/state to the command output that proves it
Layer 2 Switching or VLANs & Spanning Tree
Troubleshoot a deliberately created L2 loop and document the exact show commands that isolate it
Configure and validate voice VLAN, native VLAN mismatch handling, and trunk pruning behavior
Compare RSTP, VSTP, and MSTP failover timing in the lab and record measured convergence for each
Interpret show spanning-tree interface detail output to locate a blocked redundant link
Your checkpoint
A written failure-analysis report covering one loop scenario and one STP convergence test with measured timings
OSPF
Configure single-area OSPFv2 across three Junos routers and confirm two-way adjacency with show ospf neighbor
Tune hello/dead timers and verify mismatch behavior in logs
Configure OSPFv3 for IPv6 and verify adjacencies separately from OSPFv2
Explain and verify DR/BDR election outcomes on a shared segment by manipulating priority
Your checkpoint
An adjacency troubleshooting matrix listing five misconfigurations, each with the show command output that reveals it
OSPF & Protocol Independent Routing
Configure multi-area OSPF with an ABR and verify inter-area routes as O IA in the routing table
Configure and test virtual links and stub/NSSA area types and confirm the resulting LSA types
Implement route redistribution between OSPF and static routes using policy-statement with explicit metric and metric-type
Verify Protocol Independent Routing behavior by comparing preference values across static, OSPF, and direct routes
Your checkpoint
A multi-area topology diagram annotated with LSA types per area plus a capture of show ospf database summaries for each area
IS-IS
Configure IS-IS Level 1 and Level 2 on Junos and verify adjacency levels with show isis adjacency
Explain NET addressing and configure a valid area/system-ID layout for a four-router topology
Configure wide metrics and verify metric propagation across levels
Compare IS-IS and OSPF route selection behavior for the same topology in the lab
Your checkpoint
A side-by-side configuration and output comparison of IS-IS versus OSPF for an identical 4-router topology
BGP
Establish an eBGP session and verify state with show bgp summary, then break it and read the state reason
Establish iBGP full mesh and demonstrate the need for next-hop-self or IGP reachability
Configure route reflection and confirm cluster behavior with show bgp neighbor
Apply and verify a BGP import/export policy that filters prefixes by community
Your checkpoint
A BGP lab workbook containing session establishment, one broken-session diagnosis, and a policy filtering proof via show route receive-protocol bgp
Tunnels & Layer 2 Security
Configure GRE and IP-IP tunnels between Junos routers and verify tunnel interface state and MTU behavior
Configure an IPsec tunnel with a specific proposal/policy pair and confirm SA establishment
Harden an access port with MAC limiting, DHCP snooping, and dynamic ARP inspection, then test each control
Configure port security violation actions and verify errdisable recovery behavior
Your checkpoint
A tunnel and L2-security lab sheet with one successful and one intentionally failing control per technology, each with the verification command used
High Availability & Protocol Independent Routing
Configure VRRP and verify master/backup transition by disabling the master interface
Configure graceful restart for OSPF and BGP and observe helper behavior in logs
Configure link aggregation with LACP and verify that a member failure does not drop the bundle
Complete a timed 60-question mixed practice set and review every missed item by domain
Your checkpoint
A final readiness scorecard: per-domain practice-set accuracy, a list of remaining weak areas, and a dated retest plan
Milestones
Week 2: Can configure, verify, and troubleshoot RSTP/VSTP without notes, and correctly identify the blocked port from raw show output in under 2 minutes
Week 4: Can build a multi-area OSPF topology from a blank config and explain each LSA type present in each area
Week 6: Can diagnose a down BGP session to its root cause and fix it using only show command output, and explain route reflection without references
Week 8: Scores at least 80% overall on the timed mixed practice set with no single domain below 70%