Which statement about Policy-Based Tunnel Selection implementation on Cisco CRS Series is true?
Policy-Based Tunnel Selection (PBTS) is a feature that allows traffic to be directed into specific tunnels based on specific policies or criteria. This feature is typically used in Multiprotocol Label Switching (MPLS) networks, where different traffic types may require different paths through the network.
In the context of the Cisco CRS Series, the correct answer is B: IGP and LDP are the default path for traffic that do not meet any of the classification criteria.
The Cisco CRS Series is a high-end carrier-grade router that is designed for use in large-scale service provider networks. PBTS is one of the features that is supported on this platform, and it allows service providers to define policies that can be used to select specific tunnels for different types of traffic.
However, load balancing across multiple MPLS TE tunnels is not supported on the Cisco CRS Series (answer A is incorrect). This means that if multiple tunnels are available, PBTS will not automatically balance traffic between them.
Answer C is partially correct. PBTS can use classification criteria such as IP precedence, EXP, or TOS fields in the packet to determine which tunnel to use for specific traffic. However, this is not the only criteria that can be used. Other criteria can include the source or destination IP address, the source or destination port number, or the protocol type.
Answer D is incorrect. PBTS can be used independently of policy-based routing (PBR) on the Cisco CRS Series. PBR is a separate feature that allows network administrators to define routing policies based on various criteria, such as source IP address, destination IP address, or protocol type.
In summary, the correct answer to the question is B. IGP and LDP are the default path for traffic that do not meet any of the classification criteria, and PBTS can be used independently of PBR on the Cisco CRS Series.