Algorithm (DUAL) for calculating routes. A balanced hybrid protocol exchanges more
topology information than does a distance vector routing protocol, but it does not require full
topology and does not require the computationally intensive Dijkstra algorithm for computing
loop-free routes.
covered on the CCNA exam; only RIP Version 1 (RIP-1) and IGRP should be covered in-depth.
RIP-1 and IGRP are similar in most details, with the big exception being that IGRP uses a much
more robust metric. Both RIP-1 and IGRP are covered in more detail later in this chapter.
2 (RIP-2). RIP-2 includes many improvements over RIP-1. Most notably, the subnet mask
associated with each advertised route is included in the routing update. The mask allows routers
to use features such as variable-length subnet masks (VLSMs) and route summarization, both
features sure to be covered on the CCNP exams.
advanced features to avoid loops and speed convergence. (EIGRP is also unlikely to be covered
on the CCNA exam but is fair game for the CCNP.) The underlying algorithm is called the
be used if the current route fails. An alternate route, using what DUAL defines as a neighboring
and route summarization are easily supported.
avoid routing loops by transmitting and keeping more detailed topology information, which
allows the protocol to use calculations that prevent loops. With OSPF, the subnet mask
information is also transmitted, allowing features such as VLSM and route summarization.
routing protocol includes subnet mask information in the routing updates is listed for future
reference.