Chapter Summary and Review

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Building a fault-tolerant, rapid-recovery network is a concept that is new to the data world. One reason for this is that data communications philosophy hinges on the premise that the data will either reach its destination or be retransmitted until it does. This philosophy does not work well in voice networks. To ensure that MPLS is both competitive with ATM and on par with voice networks, rapid-recovery procedures must be implemented.

Several methods of providing network protection are currently under study. Vendors recommend approaches that are supported by their overall design concepts and specifications; therefore, failure-recovery procedures and protocols are not necessarily interoperable among different vendors. Design teams must carefully select vendors with interoperable recovery methods.

The failure-recovery method that has received much favorable press lately is RSVP-TE. The soft-state operations of RSVP-TE make it very suitable for failure recovery. One reason is that the polling (reservation/path) functions are already in place for signaling. If RSVP-TE is already used for a signaling protocol, it makes for a logical selection in protection of MPLS tunnels.

Knowledge Review 

Answer the following true/false questions.

  1. A challenge for MPLS networks is to recover from a failure within 60ms.

  2. Despite many of its disadvantages, most routing protocols use adaptations of the error message method for network recovery.

  3. The one-to-one redundancy method of network protection is the most effective and reliable but is also the most expensive to implement.

  4. The MPLS failure recovery protocol must only be able to perform rapid switching.

  5. LDP and CR-LDP protocols are best suited for the error message method of error detection in an MPLS network.

  6. RSVP-TE is best suited for the heartbeat method of error detection in an MPLS network.

Answers: 1. True; 2. true; 3. true; 4. false; 5. true; 6. true.



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Rick Gallagher's MPLS Training Guide. Building Multi-Protocol Label Switching Networks
Rick Gallahers MPLS Training Guide: Building Multi Protocol Label Switching Networks
ISBN: 1932266003
EAN: 2147483647
Year: 2003
Pages: 138

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