Juniper JN0-649 Dumps Questions Answers

Understanding the Configuration:

The provided configuration and output snippets show how traffic is classified and assigned to different forwarding classes based on the IP precedence values.

The inet-precedence classifier maps specific IP precedence values to forwarding classes with associated loss priorities.

Review of Classifiers:

IP Precedence Value 100:

The IP precedence value 100 in binary is represented as 100 (binary for 4).

Matching with Classifiers:

According to the configuration shown in the exhibit:

classifiers {

inet-precedence cos;

}

The classifier cos maps the following:

forwarding-class expedited-forwarding;

loss-priority low code-points 100;

Conclusion:

The IP precedence value 100 matches the expedited-forwarding forwarding class with low loss-priority as per the configuration.

In OSPF, the ExStart state indicates that the routers are attempting to establish a relationship and exchange information about their MTU settings. If the MTU settings do not match between the two routers on the link, it can prevent the adjacency from progressing past the ExStart state.

References:

From the image provided, you can see that the OSPF adjacency on the interface ge-0/0/2.0 is stuck in the ExStart state.

This state often suggests that there is a mismatch in the MTU settings between the routers on that interface.

To resolve this, ensure that both interfaces have the same MTU setting. You can check and set the MTU on Juniper routers using the following commands:

# Check current MTU settings

show interfaces ge-0/0/2

# Set MTU to a specific value (e.g., 1500)

set interfaces ge-0/0/2 mtu 1500

# Commit the configuration

commit

OSPF Protocol Basics:

OSPF (Open Shortest Path First) is a link-state routing protocol.

Routers exchange LSAs (Link-State Advertisements) to share topology information.

LSA Acknowledgment Mechanism:

OSPF uses a reliable mechanism to ensure LSAs are received.

When a router sends an LSA to a neighbor, it expects an acknowledgment (ACK).

If an ACK is not received within a certain period, the router will retransmit the LSA.

Acknowledgment Process:

LSAs are sent over OSPF's reliable transport, which ensures delivery through acknowledgments.

This mechanism helps to maintain consistent and up-to-date topology databases across routers.

References:

OSPF RFC 2328

Understanding OSPF Operations