Service Provider Routing and Switching

Here you have the best Juniper JN0-661 practice exam questions

  • You have 65 total questions across 13 pages (5 per page)
  • These questions were last updated on March 31, 2026
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Question 1 of 65

Click the Exhibit button.

[edit]

user@PE-1# run show l2 circuit connections

Layer-2 Circuit Connections:Legend for connection status (St)

  • EI - - encapsulation invalid NP - - interface h/w not present
  • MM - - mtu mismatch Dn - - down
  • EM - - encapsulation mismatch VC-Dn - -

Virtual circuit Down -CM - - control-word mismatch Up - -

operationalVM - - vlan id mismatch CF - - Call

  • admission control failure
  • OL - - no outgoing label IB - - TDM
  • incompatible bitrare
  • NC - - intf encaps not CCC/TCC TM - - TDM
  • misconfiguration
  • BK - - Backup Connection ST - - Standby

Connection -CB - - rcvd cell-bundle size bad SP - - Static

Pseudowire -LD - - local site signaled down RS - - remote

site standbyRD - - remote site signaled down XX - - unknown

Legend for interface status -

  • Up - - operational -
  • Dn - - down -

Neighbor: 4.4.4.4 -Interface Type St Timelast up #Up trans

ge-0/0/1.512 (vc 1) rmt OL

[edit]

user@PE-1# show protocols ldp

interface ge-0/0/2.0;

[edit]

user@PE-1# show protocols l2circuit

neighbor 4.4.4.4 {interface ge-0/0/1.512 {virtual-circuit-id 1}}

[edit]

user@PE-1# show interfaces ge-0/0/1

vlan-tagging;encapsulation vlan-ccc;unit 512 {encapsulation vlan-ccc;vlan-id 512;}

[edit]

uxer@P-1 # show protocols ldp

interface all;

[edit]

user@P-2# show protocols ldp

interface all;

[edit]

user@PE-2# run show l2circuit connections

Layer-2 Circuit Connections:Legend For connection status (St)

  • EI - - encapsulation invalid NP - - interface h/w not present
  • MM - - mtu mismatch Dn - - down
  • EM - - encapsulation mismatch VC-Dn - -

Virtual circuit Down -CM - - control-word mismatch Up - -

operationalVM - - vlan id mismatch CF - - Call

  • admission control failure
  • OL - - no outgoing label IB - - TDM
  • incompatible bitrate
  • NC - - intf encaps not CCC/TCC TM - - TDM
  • misconfiguration
  • BK - - Backup Connection ST - - Standby

Connection -CB - - rcvd cell-bundle size bad SP - - Static

Psewdowire -LD - - Local site signaled down RS - - remote

site standbyRD - - remote site signaled down XX - - unknown

Legend for interface status -

  • UP - - operational -
  • DN - - down -

Neighbor: 1.1.1.1 -Interface Type St Timelast up #Up trans

ge-0/0/1.512 (vc 1) rmt OL

[edit]

user@PE-2# show protocols ldp

interface ge-0/0/2.0;

[edit]

user@PE-2# show protocols l2circuit

neighbor 1.1.1.1 {interface ge-0/0/1.512 {virtual-circuit-id 1;}}

[edit]

user@PE-2# show interfaces ge-0/0/1

vlan-tagging;encapsulation vlan-ccc;unit 512 {encapsulation vlan-ccc;vlan-id 512;}

Referring to the exhibit, you have configured an L2 circuit that connects Site-1 and Site-2, but the L2 circuit is not functioning. The topology in this scenario is shown below.Site-1 > PE-1 > P-1 > P-2 > PE-2 Site-2Which action will allow communication between Site-1 and Site-2?

Answer

Suggested Answer

The suggested answer is C.

LDP is required as the signaling protocol for Layer 2 circuits. You must include the loopback address in LDP. We enable ldp on the loopback interfaces.
Incorrect Answers:
A: The virtual circuit identifer is correctly set to 1 both at PE-1 and PE-2.
References:
https://www.juniper.net/techpubs/en_US/junos12.3/topics/example/layer-two-circuits-ethernet-configuring-detailed-solutions.html
Question 2 of 65

Which command will match communities 101:111, 111:1, and 999:1111?

Answer

Suggested Answer

The suggested answer is D.

Period (.)A wildcard character that matches any single digit in an AS number.
+ stands for one or more repetitions of term.
? stands for zero or one repetition of term.
References:
http://www.juniper.net/documentation/en_US/junos15.1/topics/usage-guidelines/policy-defining-bgp-communities-and-extended-communities-for-use- in-routing-policy-match-conditions.html#id-10243437
Question 3 of 65

Click the Exhibit button.

[edit]

user@PE-1# show protocols

rsvp {interface all;}mpls {label-switched-path p1 {from 1.1.1.1;to 4.4.4.4;no cspf;}interface all;}bgp {group Int {type Internal;local-address 1.1.1.1;family inet {unicast;}family inet-vpn {unicast;}neighbor 2.2.2.2;neighbor 3.3.3.3;neighbor 4.4.4.4;}}ospf {area 0.0.0.0 {interface ge-0/0/2.0;interf lo0.0;}}[edit]

user@p-1# show protocols

mpls {interface all;}ospf {area 0.0.0.0 {interface ge-0/0/1.0;interface ge-0/0/2.0;interface ge-1o0.0;}}[edit]

user@p-2# show protocols

mpls {interface all;}ospf {area 0.0.0.0 {interface ge-0/0/1.0;interface ge-0/0/2.0;interface ge-lo0.0;}}[edit]

user@p-2# show protocols

rsvr {interface all;}mpls {label-switched-path p2 {from 4.4.4.4;to 1.1.1.1;no-ospf}interface all;}bgp {group INT {type internal;local-address 4.4.4.4,family inet {unicast;neighbor 2.2.2.2;neighbor 3.3.3.3;neighbor 1.1.1.1;}}ospf {area 0.0.0.0 {interface ge-0/0/2.0;interface 1o0;}}Referring to the exhibit, you have configured an L3VPN that connects Site-1 and Site-2 together, but the BGP routes are being hidden on the PE routers. The topology in this scenario is shown below.Site-1 > PE-1 > P-1 > P-2 > PE-2 > Site-2Which two acttions would allow communication Site-1 and Site-2? (Choose two.)

Answer

Suggested Answer

The suggested answer is C, D.

Hidden routes usually means that routes were not labeled properly. You should enable RSVP or LDP on all routers. RSVP is already configured on PE-1 so we only need to configure it on P-1 and P-2.
References:
https://packetcorner.wordpress.com/2013/01/30/mpls-l3vpn/
Question 4 of 65
A layer 2 circuit (RFC 4447) is established between two PE routers to provide connectivity between two customer sites.
Which two statements related to this deployment are true?
Answer

Suggested Answer

The suggested answer is B, D.

Junos OS substantially supports t RFC 4447, Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP).
Martini uses directed LDP to signal the VPN label between the PE devices, Kompella uses BGP to signal the VPN label between the PE devices.
References:
https://www.juniper.net/documentation/en_US/junos15.1/topics/reference/standards/layer-2-circuit.html
Question 5 of 65

Click the exhibit button.

[edit protocols pim]

user@R1# showrp {bootstrap {family inet {priority 250;}}local {address 10.220.1.1;priority 1;group-ranges {224.1.1.11/32;224.0.0.0/4;}}}interface all;interface fxp0.0 {disable;}

[edit protocols pim]

user@R4# showrp {bootstrap {family inet {priority 249;}}local {address 10.220.1.4;priority 5;group-ranges {224.1.1.12/32;224.0.0.0/4;}}}interface all;interface fxp0.0 {disable;}

Referring to the exhibit, which router will be the RP?

Answer

Suggested Answer

The suggested answer is A.

A priority of 1 means the routing device has the least chance of becoming a designated router. Here R1 has priority 1, while R4 has priority 5. R4 will be elected the designated router and the rendezvous point (RP) for both address ranges.
Note: In a shared tree, the root of the distribution tree is a router, not a host, and is located somewhere in the core of the network. In the primary sparse mode multicast routing protocol, Protocol Independent Multicast sparse mode (PIM SM), the core router at the root of the shared tree is the rendezvous point (RP).
References:
http://www.juniper.net/documentation/en_US/junos15.1/topics/example/ospf-designated-router-election-configuring.html

About the Juniper JN0-661 Certification Exam

About the Exam

The Juniper JN0-661 (Service Provider Routing and Switching) validates your knowledge and skills. Passing demonstrates proficiency and can boost your career prospects in the field.

How to Prepare

Work through all 65 practice questions across 13 pages. Focus on understanding the reasoning behind each answer rather than memorizing responses to be ready for any variation on the real exam.

Why Practice Exams?

Practice exams help you familiarize yourself with the question format, manage your time, and reduce anxiety on the test day. Our JN0-661 questions are regularly updated to reflect the latest exam objectives.