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Juniper JN0-664 Exam - Topic 5 Question 43 Discussion

Actual exam question for Juniper's JN0-664 exam
Question #: 43
Topic #: 5
[All JN0-664 Questions]

Refer to the exhibit.

Click the Exhibit button.

PE-1 and PE-2 are configured with LDP-signaled pseudowires to provide connectivity between CE-1 and CE-2. You notice no connectivity exists between CE-1 and CE-2.

Referring to the exhibit, which two statements describe potential causes for this fault? (Choose two.)

Show Suggested Answer Hide Answer
Suggested Answer: A, B

In the provided exhibit, the configuration involves using a RIB (Routing Information Base) group to facilitate internet access for VPN-A Site 1 through PE-1. The goal is to provide VRF Internet access over a single connection.

1. **Understanding RIB Groups**:

- RIB groups allow for the import and export of routes between different routing tables.

- In this scenario, we have two RIBs: `inet.0` (the main routing table) and `VPN-A.inet.0` (the VRF-specific routing table).

2. **Statement Analysis**:

- **A. You must use the RIB group to move a default route, which is learned through BGP, from the inet.0 table to the VPN-A.inet.0 table.**

- Correct. To provide Internet access to VPN-A, the default route (0.0.0.0/0) learned via BGP in the `inet.0` table must be made available in the `VPN-A.inet.0` table. This is done using the RIB group to import the default route.

- **B. You do not need to use the RIB group to move interface routes from the inet.0 table to the VPN-A.inet.0 table.**

- Correct. Interface routes (connected routes) are typically directly added to both the global and the VRF routing tables without needing a RIB group. These routes are known to the VRF because the interfaces are part of the VRF configuration.

- **C. You do not need to use the RIB group default route, which is learned through BGP, from the inet.0 table to the VPN-A.inet.0 table.**

- Incorrect. As discussed, the default route needs to be imported into the VRF's routing table using a RIB group to enable Internet access for the VRF.

- **D. You must use the RIB group to move interface routes from the inet.0 table to the VPN-A.inet.0 table.**

- Incorrect. Interface routes are directly associated with the VRF interfaces and are automatically known to the VRF routing table. There is no need to use a RIB group for these routes.

**Conclusion**:

The correct answers are:

**A. You must use the RIB group to move a default route, which is learned through BGP, from the inet.0 table to the VPN-A.inet.0 table.**

**B. You do not need to use the RIB group to move interface routes from the inet.0 table to the VPN-A.inet.0 table.**

**Reference**:

- Juniper Networks Documentation on RIB Groups: [RIB Groups Overview](https://www.juniper.net/documentation/en_US/junos/topics/concept/rib-groups-overview.html)

- Junos OS VPNs Configuration Guide: [Junos VPNs Configuration](https://www.juniper.net/documentation/en_US/junos/topics/concept/vpns-overview.html)


Contribute your Thoughts:

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Tyra
3 months ago
Wait, are you saying mismatched VC IDs can cause this? That's wild!
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Loren
3 months ago
I disagree, I don't think the interface is the problem here.
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Marcelle
3 months ago
Interface ge-0/0/0 being down could also be a reason.
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Detra
4 months ago
I think it's more likely there's no LSP from PE-1 to PE-2.
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Adelle
4 months ago
The VC IDs are definitely a common issue.
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Tenesha
4 months ago
I’m leaning towards the idea that both LSP configurations need to be checked. I recall a similar question where both directions were important for the pseudowire to work.
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Luisa
4 months ago
I feel like interface status could play a role too. If ge-0/0/0 on PE-1 is down, that might prevent connectivity as well.
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Hyman
4 months ago
I’m not entirely sure, but I think if there’s no LSP from PE-1 to PE-2, that could also be a problem. It sounds familiar from our practice questions.
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Arminda
5 months ago
I remember something about VC IDs being crucial for connectivity. If they're mismatched, that could definitely cause issues.
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Osvaldo
5 months ago
I'm a little confused by the terminology in this question. What exactly is an "LSP" and how does it relate to the pseudowire configuration? I'll need to review my notes on MPLS and VPNs to make sure I understand the underlying technology before I can confidently answer this.
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Cherry
5 months ago
Okay, I've got this. The key here is to focus on the connectivity between the PE routers, PE-1 and PE-2. The question states there's no connectivity between the CE routers, so the problem must be in the service provider network. I'll carefully consider the options and select the two most likely causes.
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Joye
5 months ago
Hmm, I'm a bit unsure about this one. The question is asking about the potential causes, but there are a lot of moving parts in this network setup. I'll need to think through the LDP-signaled pseudowire configuration and connectivity requirements to determine the most likely issues.
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Alpha
5 months ago
This looks like a pretty straightforward question about troubleshooting a pseudowire connectivity issue. I'll start by carefully reviewing the exhibit and the provided information to identify the potential causes.
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Cherry
9 months ago
This is why we can't have nice things. Pseudowires and LSPs, the IT equivalent of herding cats.
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Miles
8 months ago
I think we need to check the VC IDs and interface status to troubleshoot this issue.
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Celeste
8 months ago
C) Interface ge-0/0/0 on PE-1 is down.
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Jenelle
8 months ago
A) The VC IDs are mismatched.
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Aide
9 months ago
No LSP from PE-2 to PE-1? Well, that's just asking for trouble. Looks like someone needs a refresher on MPLS 101.
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Loise
9 months ago
The interface on PE-1 is down? That's just plain ol' bad luck. Time to grab a screwdriver and get to work!
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Christene
9 months ago
No LSP between the PEs? That's a rookie mistake. You can't have a pseudowire without an underlying LSP. Gotta get those MPLS paths set up first.
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Marsha
8 months ago
True, without the LSP, the pseudowire won't work.
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Helene
8 months ago
Oops, looks like someone forgot to check the VC IDs.
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Ludivina
8 months ago
C) Interface ge-0/0/0 on PE-1 is down.
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Natalie
8 months ago
A) The VC IDs are mismatched.
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Rosalind
10 months ago
Hmm, the VC IDs must be mismatched. That's a common issue with pseudowires. Should've double-checked those before deployment.
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Kate
9 months ago
User 2: Yeah, that could be causing the connectivity issue.
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Renea
10 months ago
User 1: The VC IDs are mismatched.
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Jennie
11 months ago
I believe both A) The VC IDs are mismatched and C) Interface ge-0/0/0 on PE-1 is down could be causing the fault.
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Sylvie
11 months ago
I agree with Ruthann. Another potential cause could be that Interface ge-0/0/0 on PE-1 is down.
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Ruthann
11 months ago
I think the potential cause could be that the VC IDs are mismatched.
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