CCIE SP MPLS FAQ: MPLS VPN Troubleshooting Figure: Sample MPLS VPN Network Q1. What are the common errors that occur in an MPLS VPN network that are not a result of MPLS VPN design or configuration error? Answer: The common errors, apart from the users reporting a network error when something else is broken, are MPLS MTU issues in the core of the MPLS backbone and … [Read more...]
CCIE SP MPLS FAQ: IP Tunneling to MPLS/VPN Migration Case Study
CCIE SP MPLS FAQ: IP Tunneling to MPLS/VPN Migration Case Study Figure: SampleNet VPN Connectivity Using GRE Tunnels Q1. List two of the several items that must be addressed during the migration planning stage. Answer: Define the deployment requirements. Assign the necessary naming conventions. Define the RD and RT format. Define the PE-CE link … [Read more...]
CCIE SP MPLS FAQ: Carrier’s Carrier and Inter-provider VPN Solutions
CCIE SP MPLS FAQ: Carrier’s Carrier and Inter-provider VPN Solutions Q1. Which architecture can you use to reduce the overhead on PE routers for VPN clients that want to exchange large amounts of routing information between their sites? Answer: The carrier's carrier architecture. Figure: Carrier's Carrier—No MPLS Within ISP Sites Q2. How does the carrier's carrier … [Read more...]
CCIE SP MPLS FAQ: Guidelines for the Deployment of MPLS/VPN
CCIE SP MPLS FAQ: Guidelines for the Deployment of MPLS/VPN Q1. In an IP routed backbone, why is it necessary for P routers to hold full external routing information? Answer: P routers forward packets based on their destination IP address. If this address is not within the forwarding table the packets are Q2. How does the full routing requirement change with the introduction … [Read more...]
CCIE SP MPLS FAQ: Advanced MPLS/VPN Topics
CCIE SP MPLS FAQ: Advanced MPLS/VPN Topics Figure: VPN and Backbone Network Convergence 1: During periods of convergence, why does a cell-mode MPLS implementation typically take longer to converge than a frame-mode implementation? Answer: Cell-mode MPLS uses downstream-on-demand label distribution with conservative retention mode This means that an upstream 2: How … [Read more...]
CCIE SP MPLS FAQ: Provider Edge (PE) to Customer Edge (CE) Connectivity Options
CCIE SP MPLS FAQ: Provider Edge (PE) to Customer Edge (CE) Connectivity Options Figure: PE-to-CE Connectivity Options—Sample Topology Q1. What are the four ways in which routing information can currently be learned from a CE router? Answer: Static, BGP, OSPF, and RIP version 2. Q2. When running a dynamic routing protocol between PE and CE, how can the PE identify … [Read more...]
CCIE SP MPLS FAQ: MPLS/VPN Architecture Operation
CCIE SP MPLS FAQ: MPLS/VPN Architecture Operation Figure: Basic MPLS/VPN Intranet Topology Structure Q1. Using the basic MPLS VPN mechanisms, is it possible to have overlapping IP addresses within the same extranet VPN? Answer: No. During the import process, one or more updates are lost because BGP selects one as the best path to the given Q2. How can the issue of … [Read more...]
CCIE SP MPLS FAQ: MPLS/VPN Architecture Overview
CCIE SP MPLS FAQ: MPLS/VPN Architecture Overview Figure: Virtual Routers Created in a PE Router Q1. How can overlapping IP addresses be supported between customer sites when MPLS VPN is deployed? Answer: Each VPN has access to its own routing and forwarding tables Q2. What routing information is contained within the global routing table on PE routers? Answer: Routes … [Read more...]
CCIE SP MPLS FAQ: MPLS Troubleshooting
CCIE SP MPLS FAQ: MPLS Troubleshooting Q1. What are the prerequisites for successful MPLS deployment? Answer: MPLS requires CEF enabled globally and on all interfaces on which the label imposition needs to be performed. Q2. What are the reasons that a TDP neighbor would not be discovered? Answer: A TDP neighbor would not be discovered because of a protocol mismatch (TDP … [Read more...]
CCIE SP MPLS FAQ: MPLS Migration and Configuration Case Study
CCIE SP MPLS FAQ: MPLS Migration and Configuration Case Study Figure: TransitNet Backbone Network Topology Q1. Carrying external customer routes within BGP has two advantages; list them. Answer: Having numerous routes within the IGP can lead to stability and scalability issues that are not present within BGP. The internal routing infrastructure of the service provider … [Read more...]