JNCIP-SP JN0-664 Passing Score

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Question 8

Click the Exhibit button.

You are troubleshooting an issue for a customer site that uses 10.10.0.0/24 in AS 65224, but you see another AS in the AS path.

Referring to the exhibit, what is the cause of the problem?

Options:

AS 65000 is pre-pending AS 65137 to route advertisements.

The local AS is receiving two equal cost routes to 10.10.0.0/24.

The local AS is in the process of withdrawing the route from AS 65137.

AS 65137 is advertising the 10.10.0.0/24 prefix.

Answer:

Explanation:

In the given exhibit, you are observing the BGP routing information for the prefix 10.10.0.0/24. The AS path for this prefix shows `65000 {65137 65224}`. To understand the issue, let's analyze each aspect of the information provided and the options given:

1. **AS Path Analysis**:

- The AS path attribute in BGP is a list of AS numbers that a route advertisement has traversed.

- In this case, the AS path `65000 {65137 65224}` indicates that the route to 10.10.0.0/24 has been advertised through AS 65000, which includes AS 65137 and AS 65224.

2. **Understanding AS Path Prepending**:

- AS path prepending is a technique used by AS administrators to artificially lengthen the AS path.

- By adding their own AS number multiple times into the AS path, they make a route less attractive to others.

- Here, AS 65000 is showing `65137` as part of its AS path, suggesting it might be prepending to manipulate routing decisions.

3. **Options Analysis**:

- **Option A**: "AS 65000 is pre-pending AS 65137 to route advertisements."

- This option suggests that AS 65000 is deliberately adding AS 65137 to the AS path. This matches the observed AS path, where AS 65000 has prepended `65137`.

- Therefore, this is the correct explanation.

- **Option B**: "The local AS is receiving two equal cost routes to 10.10.0.0/24."

- There is no evidence in the exhibit to support the presence of two equal-cost routes.

- **Option C**: "The local AS is in the process of withdrawing the route from AS 65137."

- Route withdrawal would not cause the AS path to include `65000 {65137 65224}`.

- **Option D**: "AS 65137 is advertising the 10.10.0.0/24 prefix."

- While AS 65137 is part of the path, it does not explain the presence of AS 65000 in the path, making this option incorrect.

**Conclusion**:

The AS path `65000 {65137 65224}` is indicative of AS 65000 prepending AS 65137. Therefore, the correct answer is:

**A. AS 65000 is pre-pending AS 65137 to route advertisements.**

**References**:

- Juniper Networks documentation on BGP AS path manipulation and prepending techniques.

- BGP Best Practices and Routing Policies: [Juniper Networks BGP Best Practices](https://www.juniper.net/documentation/en_US/junos/topics/concept/bgp-best-practices-routing-policies.html)

- RFC 4271, A Border Gateway Protocol 4 (BGP-4): [RFC 4271](https://tools.ietf.org/html/rfc4271) which describes the behavior and attributes of BGP, including AS path prepending.

Question 9

Which two statements are correct about VPLS tunnels? (Choose two.)

Options:

LDP-signaled VPLS tunnels only support control bit 0.

LDP-signaled VPLS tunnels use auto-discovery to provision sites

BGP-signaled VPLS tunnels can use either RSVP or LDP between the PE routers.

BGP-signaled VPLS tunnels require manual provisioning of sites.

Question 10

Your network is receiving the 203.0.113.0/24 network using EBGP from AS 64500 and AS 64501. Both of these advertisements have identical local-preference values, AS-path lengths, and BGP origin codes. You want to influence the way your AS sends traffic to the 203.0.113.0/24 network.

In this scenario, which attribute would you consider next when selecting the best path?

Options:

router ID

MED value

peer IP address

IGP metric

Question 11

Exhibit

R4 is directly connected to both RPs (R2 and R3) R4 is currently sending all ,o,ns upstream to R3 but you want all joins to go to R2 instead Referring to the exhibit, which configuration change will solve this issue?