Juniper MX Series

Chapter Review Answers

1. Answer: A. There’s only a single VLAN ID in IEEE 802.1Q.

2. Answer: B,C. This is a tricky one, as both stacked-vlan-tagging and flexible-vlan-tagging will support IEEE 802.1QinQ frames.

3. Answer: C,D. When using encapsulation flexible-ethernet-services, this enables per IFL encapsulation, which is most often used when supporting multiple customers per port.

4. Answer: A. The Enterprise Style supports basic VLAN mapping via the family bridge vlan-rewrite function.

5. Answer: C. The ingress frame has a single C-TAG and the objective is to perform VLAN mapping to support both a S-TAG and a C-TAG. The tricky part of the requirement is that the original C-TAG is removed and the remaining S-TAG and a C-TAG are completely different VLAN IDs. The stack operation swap-push will swap the outer tag and push a new tag, resulting in the proper S-TAG and C-TAG.

6. Answer: B. When a bridge domain is configured with vlan-id none, it supports a single bridge domain and learning domain; it also requires that you use input-vlan-map and output-vlan-map to perform VLAN mapping.

7. Answer: D. When a bridge domain is configured with vlan-id all, it supports a single bridge domain with 4,094 learning domains.

8. Answer: D. MAC accounting will enable per MAC statistics that keep track of how many times it has been used as a source or destination address. Use the show route forwarding-table command to verify.

9. Answer: B. The interface irb is automatically set to a speed of 1,000 Mbps; however, this doesn’t actually ...