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254 Chapter 10

ing together. If we converge and take the best of both worlds, we can
migrate to what appears in Figure 10-14 and have a combined net-
working strategy, which is what the other services have been trying
to achieve.

Another Thought

In 1992, I wrote a book on disaster recovery planning for telecom-
munications networks. In that book, several concepts were discussed
regarding the guaranteed connections, the redundant networking
strategies, and the recovery efforts for an end-user and carrier alike.
The main thought was to use the dual-fed fiber in a building and
place half of the mission-critical services on each of the feeds. That
way, in the event of backhoe fade (a cable cut), only half of the mis-
sion-critical services would be potentially impacted. Moreover, by
having SONET architecture, we could automatically recover by
using the benefits of the ring topology.
The assumption that I made when writing about this was that the
carriers would have fiber to the door for all of their business cus-
tomers.That fiber would also be fed via a SONET ring.The reality is
that this has not happened as quickly as we expected and it has only
recently begun to appear. Large customers can take advantage of
the fiber feeds to a building and they are using the range of OC-1 to
OC-3. That means that the end users are still stuck on 50- to 155-

Figure 10-14
Convergence in
the future