JNCIS-SP study guide
JNCIS-SP · Work through your exam, one topic at a time.
The Juniper Networks Certified Internet Specialist – Service Provider Routing and Switching (JNCIS-SP) is a mid-tier certification for network engineers who design, build, and operate service provider infrastructures on Junos OS. It sits above the associate-level JNCIA-Junos and below the professional JNCIP-SP, so it is the natural stepping stone for engineers moving from device-level configuration into protocol-level troubleshooting. The JNCIS-SP study guide has 6 sections and about 2,056 words.
01OSPF: Multi-Area Design, Area Types, Metrics, and Convergence
OSPF scales by splitting the topology into areas, and every non-backbone area must touch area 0.0.0.0 (directly or through a virtual link). A router with interfaces in two areas is an ABR and condenses topology into Type 3 summary LSAs.
355 words, about 2 min02IS-IS: Levels, Addressing, Metrics, and Convergence
IS-IS runs directly over CLNS, so it can route before IP is configured. Every router needs a unique NET in the form 49.0001.1921.6800.1001.00 : the leading bytes are the area ID , the middle 6 bytes the system ID , and the trailing 00 the NSEL (always 00).
364 words, about 2 min03BGP: Peering, Path Selection, Route Reflection, and Communities
iBGP peers do not require direct connectivity in concept, but the next hop must be reachable via the IGP, and multihop plus local-address are typically needed. Because iBGP does not re-advertise iBGP-learned routes to other iBGP peers, you need a full mesh, route reflectors, or confederations.
326 words, about 2 min04MPLS and Layer 3 VPNs: LDP, RSVP-TE, Label Stacking, and VRFs
LDP distributes labels bound to IGP routes and simply follows the IGP shortest path. Enable it on the loopback interface too - if the loopback is not an LDP interface, the LSP to a BGP next hop never forms and VPN routes stay unusable.
357 words, about 2 min05Layer 2 Switching at the Service Provider Edge
Access ports carry a single untagged VLAN; trunk ports carry 802.1Q-tagged frames for every VLAN in their membership list. On Junos, interface-mode trunk with vlan members (explicit list or all ) must agree on both ends of the link, and the native VLAN is the one sent untagged - the native VLAN ID must match on both sides.
331 words, about 2 min06Routing Policy, Filtering, and High Availability
A Junos policy-statement contains ordered term s. Each term matches conditions in from (protocol, prefix-list, route-filter, community, as-path, neighbor, interface) and applies actions in then (accept, reject, next term, local-preference, metric, community add/delete, as-path prepend, next-hop).
323 words, about 2 min