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Exam Information
Official specifications published by Juniper
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Skills this practice test covers
- Trace LSA flooding in multi-area OSPF and LSP flooding in multi-area IS-IS.
- Predict which path the BGP route selection process picks, then steer it with policy.
- Assign traffic to forwarding classes and queue it with schedulers and drop profiles.
- Follow a multicast stream from IGMP joins through PIM sparse mode and the RP.
- Use route targets, site of origin and sham links to control Layer 3 VPN routing.
- Compare the four Layer 2 VPN types, from LDP Layer 2 circuits to EVPN multihoming.
Explore related topics
JN0-664 exam content
7 domains · 44 topics · 200 of 272 questions are written for JN0-664
OSPF29 questions
This domain covers OSPFv2 and OSPFv3 in networks with many areas. Candidates explain area types, LSA flooding, designated router operation, the SPF algorithm and metrics, then apply OSPF routing policy in a scenario.
Skills tested
- Explain which LSAs each OSPF area type accepts and how they flood between areas.
- Summarize and restrict routes, and choose an external metric type.
- Join a remote area to the backbone with a virtual link.
- Compare OSPFv2 with OSPFv3 and write an OSPF routing policy.
Questions by topic
- OSPF area types and operations6
- Virtual links4
- Summarize and restrict routes6
- OSPFv2 vs. OSPFv34
- Implement OSPF routing policy3
- Link-state advertisement (LSA) flooding through an OSPF multi-area network6
IS-IS23 questions
IS-IS follows the same pattern as OSPF: first how the protocol works, then a scenario about configuring or monitoring it. The topics are areas and levels, LSP flooding, DIS operation, the SPF algorithm, wide metrics, and route summarization and leaking.
Skills tested
- Explain how Level 1 and Level 2 routing work across IS-IS areas.
- Describe what the designated intermediate system does on a broadcast segment.
- Compare narrow and wide metrics in an IS-IS design.
- Leak Level 2 routes into a Level 1 area with a routing policy.
Questions by topic
- IS-IS areas/levels and operations9
- Metrics, including wide metrics4
- Designated intermediate system (DIS) operation4
- Route summarization and route leaking6
BGP37 questions
This domain goes well past basic peering. Candidates explain the route selection process, attributes, communities, regular expressions, multipath, multihop, damping and flowspec, and scale internal BGP with route reflection.
Skills tested
- Walk the BGP route selection process to find which path wins.
- Match AS paths with regular expressions in a routing policy.
- Tag routes with communities and act on the tags in policy.
- Configure route reflection so internal BGP scales without a full mesh.
- Explain how BGP flowspec spreads filter rules to other routers.
Questions by topic
- BGP route selection process5
- BGP route damping4
- BGP attributes—concept and operation3
- BGP communities5
- Route reflection6
- Multipath5
- Implement BGP routing policy2
- Advanced BGP options7
Class of Service (CoS)28 questions
This domain follows a packet through CoS processing on a Junos OS device. Candidates classify traffic into forwarding classes, set loss priority, police and schedule it, drop it with drop profiles under congestion, and mark it again with rewrite rules.
Skills tested
- Choose between behavior aggregate and multifield classification.
- Map traffic to forwarding classes and set packet loss priority.
- Configure schedulers and drop profiles for each queue.
- Write rewrite rules that mark CoS header fields as packets leave.
Questions by topic
- Schedulers4
- Policers4
- Classification4
- Rewrite rules4
- Forwarding classes6
- Drop profiles6
IP Multicast20 questions
This domain explains how one stream reaches many receivers. It covers multicast addressing, IGMP, PIM dense mode and sparse mode, RPF checks, rendezvous points, anycast RP, and the difference between any-source and source-specific multicast.
Skills tested
- Explain how hosts join multicast groups with IGMP.
- Compare PIM dense mode with PIM sparse mode.
- Describe how routers discover and elect a rendezvous point.
- Explain the RPF check and how it prevents multicast loops.
- State the requirements, benefits and address ranges of SSM.
Questions by topic
- Anycast rendezvous point (RP)6
- Internet Group Management Protocol (IGMP)5
- PIM dense mode and sparse mode6
- Reverse path forwarding (RPF)—concept and operation3
Layer 3 VPNs31 questions
This domain covers VPNs in which provider routers keep customer routes apart in VRF tables. Candidates explain route distinguishers, route targets, site of origin, sham links and VRF table-label, plus multicast VPNs, IPv6 VPNs, Internet access and carrier-of-carriers models.
Skills tested
- Explain how route distinguishers make VPN-IPv4 addresses unique.
- Build full mesh and hub-and-spoke VPNs with route targets.
- Stop loops with site of origin, and prefer the VPN over a backdoor link with a sham link.
- Compare carrier-of-carriers and inter-provider VPN models in Junos OS.
Questions by topic
- Site of origin4
- Junos OS support for carrier-of-carriers or inter-provider VPN models6
- Route distinguishers3
- Configure or monitor the components of Layer 3 VPNs3
- Traffic flow—control and data planes5
- Layer 3 VPN Internet access options4
- Virtual routing and forwarding (VRF) table-label4
- Sham links2
Layer 2 VPNs32 questions
The last domain covers four ways to carry Layer 2 traffic across a provider network: LDP Layer 2 circuits, BGP Layer 2 VPNs, VPLS and EVPN. For each, candidates explain the control plane and the data plane, and the scenario objective adds troubleshooting.
Skills tested
- Explain connection mapping and the Layer 2 VPN NLRI in BGP Layer 2 VPNs.
- Describe the virtual circuit label and autodiscovery in LDP Layer 2 circuits.
- Compare BGP and LDP label distribution in VPLS.
- Explain MAC learning and multihoming in EVPN.
Questions by topic
- Ethernet VPN (EVPN) multihoming8
- LDP VPLS label distribution3
- LDP Layer 2 circuits4
- BGP VPLS label distribution3
- VPLS multihoming4
- Media access control (MAC) learning and distribution3
- BGP EVPN label distribution3
- Traffic flow—control and data planes4
Requirements
- Required: the JNCIS-SP certification.
- Recommended: Juniper's AJSPR, JL2V and JL3V courses, which Juniper names with the TechLibrary as the source of its questions.
- Recommended: working knowledge of MPLS, which the Layer 2 and Layer 3 VPN objectives build on.
About the JN0-664 exam
JN0-664 is the written exam that earns JNCIP-SP, Juniper's professional certification for engineers who build service provider networks on the Junos operating system. Its seven domains run from the link-state protocols OSPF and IS-IS through BGP to class of service, multicast, and VPNs at Layer 2 and Layer 3. Most objectives ask how a feature works, and each domain adds a scenario about configuring or monitoring it. Candidates need the JNCIS-SP certification first, and JNCIP-SP stays valid for three years.
The PlanetCert practice test spreads its questions over all seven domains, with the most on BGP and the two VPN domains. Each answer comes with an explanation, which helps most where two options differ by one detail, such as a route distinguisher and a route target. Study Mode suits the Class of Service (CoS) domain, where a packet meets classifiers and policers on the way in and schedulers and rewrite rules on the way out. Brainy AI Assistant can compare VPLS with EVPN, or explain why an RPF check drops a multicast packet.
How to earn the certification
- Earns
- JNCIP-SP (Service Provider Routing and Switching, Professional)Professional
JNCIP-SP is valid for three years.
- Before
- JN0-364 Service Provider Routing and Switching, Specialist (JNCIS-SP)
Required. Juniper lists this specialist certification as the prerequisite for JNCIP-SP.
- JN0-106 Junos, Associate (JNCIA-Junos)
The associate exam at the start of the track. It covers the Junos OS basics that JNCIS-SP builds on.
- JN0-364 Service Provider Routing and Switching, Specialist (JNCIS-SP)
How to prepare for JN0-664
- 1
Split each domain into two lists
Juniper's objectives first ask how each feature works, then give a scenario to configure or monitor it. Note which items need a working lab configuration and which need a clear explanation.
- 2
Build OSPF and IS-IS in a lab
Run a few virtual Junos OS routers. Build multi-area OSPF and then two-level IS-IS, and check the link-state database each time a route is summarized or leaked.
- 3
Layer BGP and the VPNs on top
Add internal BGP with a route reflector, then build a Layer 3 VPN, a VPLS instance and an EVPN instance over it. BGP and the two VPN domains have the longest objective lists, so give them the most hours.
- 4
Sketch the CoS and multicast paths
Draw where a packet is classified, policed, queued and rewritten inside the router. Then draw a PIM sparse mode tree from a source, through the RP, to a receiver that joined with IGMP.
- 5
Practise by domain, then in full
Take the JN0-664 practice test one domain at a time in Study Mode, then a full run in Timed Mode. Ask Brainy AI Assistant to replay any missed question about route selection or label distribution.
Start a timed JN0-664run
Juniper recommends Advanced Junos Service Provider Routing (AJSPR), Junos Layer 2 VPNs (JL2V) and Junos Layer 3 VPNs (JL3V). The Juniper Learning Portal and the Juniper TechLibrary support these courses.
Who JN0-664 is for
- Engineers who hold JNCIS-SP and want the professional certification in Juniper's service provider track.
- Service provider engineers who run OSPF or IS-IS, BGP and MPLS VPNs on Junos OS.
- Engineers who design or support Layer 2 and Layer 3 VPN services for customers.
Typical job titles: Service provider network engineer · IP/MPLS engineer · Senior network engineer · Network architect · Network operations engineer
JN0-664 glossary
20 terms from the exam objectives and the vendor's official material, each defined in a sentence.
- Anycast rendezvous point (RP)
- Several rendezvous points that share one address, which gives PIM sparse mode redundancy and load sharing.
- BGP flowspec
- A BGP extension that carries traffic filter rules, with match conditions and actions, to other routers.
- BGP route damping
- A BGP feature that holds back a route that keeps flapping, so its instability does not spread.
- Designated intermediate system (DIS)
- The IS-IS router chosen on a broadcast segment to represent the segment and keep link-state databases in step.
- Drop profiles
- CoS settings that link how full a queue is to the chance that a new packet is dropped.
- Ethernet VPN (EVPN)
- A Layer 2 VPN that advertises MAC addresses in BGP, which lets one site connect to more than one provider router.
- Packet loss priority
- A CoS marking that tells the router which packets to drop first when a queue fills up.
- Reverse path forwarding (RPF)
- A multicast check that accepts a packet only if it arrives on the interface the router uses to reach the source.
- Rewrite rules
- CoS rules that set the code points in a packet header as the packet leaves an interface.
- Route distinguishers
- Values added to customer prefixes in a VPN, so the same address used by two customers stays unique in BGP.
- Route reflection
- A BGP scaling method in which a route reflector passes routes between internal BGP peers, so they do not need a full mesh of sessions.
- Route targets
- BGP extended communities attached to VPN routes on export, which decide which VRF tables import those routes.
- Sham links
- Links between two provider edge routers that OSPF treats as intra-area links, so traffic can prefer the VPN over a backdoor link.
- Site of origin
- A tag on VPN routes that stops a route learned from one customer site from being sent back into that site.
- Source-specific multicast (SSM)
- A multicast model in which receivers ask for traffic from one named source, so no rendezvous point is needed.
- Virtual circuit label
- The MPLS label that an LDP Layer 2 circuit uses to deliver frames to the right circuit at the far end.
- Virtual links
- OSPF links across a transit area that join an area to the backbone area when it has no direct connection.
- Virtual private LAN service (VPLS)
- A Layer 2 VPN that joins several customer sites into one bridged LAN across the provider network.
- VRF table-label
- A Junos OS setting that gives a VRF table one label, so the egress router does an IP lookup in that table.
- Wide metrics
- IS-IS metrics with a much larger value range than the original narrow metrics, which allows finer link costs.