Implementing a full separation model for Internet access and MPLS L3VPN services enables EGP (Exterior Gateway Protocol) and IGP (Interior Gateway Protocol) to operate independently. This separation is crucial because EGP is used to exchange routing information between different autonomous systems, while IGP is used within an autonomous system. By maintaining separate routing instances for each service, the network can achieve enhanced performance and stability, as it prevents routing conflicts and ensures each protocol operates within its optimal context.
The Cisco MPLS TE forwarding adjacency feature allows an MPLS Traffic Engineering tunnel to be advertised as a link in the Interior Gateway Protocol (IGP) routing tables. This enables the MPLS core network to facilitate traffic engineering by providing the capability to include MPLS TE tunnels as part of the IGP’s topology.
When configuring TTL security with the command 'neighbor 2.2.2.2 ttl-security hops 2', the router expects to receive BGP packets from the neighbor with a TTL value of at least 253. This is calculated as 255 (the maximum TTL value) minus the number of hops set (2). Therefore, the correct answer is that the PE accepts packets from 2.2.2.2 with a TTL of 253 or more.