tailieunhanh - MPLS VPN Design Guidelines

1. What are the drawbacks of using unnumbered links? Individual WAN interfaces are no longer reachable by ping or telnet if you use unnumbered links. 2. Where should you use unnumbered links in the MPLS backbone? Unnumbered links are recommended in the ATM parts of the MPLS backbone. 3. Where would you use unnumbered links between PE and CE routers? Using unnumbered links between PE and CE routers is highly discouraged. There are, however, applications like dial-up access that benefit from unnumbered links. 4. Why would you use private address space in your IP backbone? IP backbones usually only use private address space if there is no public address space available. 5. What. | 3 MPLS VPN Design Guidelines Backbone and PE-CE Link Addressing Scheme Lesson Review 1. What are the drawbacks of using unnumbered links Individual WAN interfaces are no longer reachable by ping or telnet if you use unnumbered links. 2. Where should you use unnumbered links in the MPLS backbone Unnumbered links are recommended in the ATM parts of the MPLS backbone. 3. Where would you use unnumbered links between PE and CE routers Using unnumbered links between PE and CE routers is highly discouraged. There are however applications like dial-up access that benefit from unnumbered links. 4. Why would you use private address space in your IP backbone IP backbones usually only use private address space if there is no public address space available. 5. What are the drawbacks of using private address space in your IP backbone Traceroute across a public IP backbone using private address space usually does not work. 6. How would you hide the private address space from your customers If you disable MPLS TTL propagation the customers cannot see the P-routers. Using private address space between P-routers is then safe. 7. What is the impact of using private backbone addresses on traceroute ICMP replies received from private IP addresses would most likely be dropped by customer firewalls. IP address lookup through DNS would also fail. 8. Why should you allocate PE loopback addresses from a separate address block The PE loopback addresses should be allocated from a separate block to make sure they are not accidentally summarized in the backbone. 9. Why should you use registered addresses for PE-CE links Registered addresses should be used on PE-CE links to prevent potential overlap with the address space the customer is using. 10. Why is the reuse of registered addresses between VRFs not advisable You should not reuse addresses between VRFs as a customer connected to a wrong interface might gain connectivity within the VPN of another customer. 11. When can you reuse registered