Cisco Systems 3560 Manual Do Utilizador
36-34
Catalyst 3560 Switch Software Configuration Guide
OL-8553-06
Chapter 36 Configuring IP Unicast Routing
Configuring EIGRP
is shown in the packet. The reliable transport has a provision to send multicast packets quickly when
there are unacknowledged packets pending. Doing so helps ensure that convergence time remains
low in the presence of varying speed links.
there are unacknowledged packets pending. Doing so helps ensure that convergence time remains
low in the presence of varying speed links.
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The DUAL finite state machine embodies the decision process for all route computations. It tracks
all routes advertised by all neighbors. DUAL uses the distance information (known as a metric) to
select efficient, loop-free paths. DUAL selects routes to be inserted into a routing table based on
feasible successors. A successor is a neighboring router used for packet forwarding that has a
least-cost path to a destination that is guaranteed not to be part of a routing loop. When there are no
feasible successors, but there are neighbors advertising the destination, a recomputation must occur.
This is the process whereby a new successor is determined. The amount of time it takes to recompute
the route affects the convergence time. Recomputation is processor-intensive; it is advantageous to
avoid recomputation if it is not necessary. When a topology change occurs, DUAL tests for feasible
successors. If there are feasible successors, it uses any it finds to avoid unnecessary recomputation.
all routes advertised by all neighbors. DUAL uses the distance information (known as a metric) to
select efficient, loop-free paths. DUAL selects routes to be inserted into a routing table based on
feasible successors. A successor is a neighboring router used for packet forwarding that has a
least-cost path to a destination that is guaranteed not to be part of a routing loop. When there are no
feasible successors, but there are neighbors advertising the destination, a recomputation must occur.
This is the process whereby a new successor is determined. The amount of time it takes to recompute
the route affects the convergence time. Recomputation is processor-intensive; it is advantageous to
avoid recomputation if it is not necessary. When a topology change occurs, DUAL tests for feasible
successors. If there are feasible successors, it uses any it finds to avoid unnecessary recomputation.
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The protocol-dependent modules are responsible for network layer protocol-specific tasks. An
example is the IP EIGRP module, which is responsible for sending and receiving EIGRP packets
that are encapsulated in IP. It is also responsible for parsing EIGRP packets and informing DUAL
of the new information received. EIGRP asks DUAL to make routing decisions, but the results are
stored in the IP routing table. EIGRP is also responsible for redistributing routes learned by other
IP routing protocols.
example is the IP EIGRP module, which is responsible for sending and receiving EIGRP packets
that are encapsulated in IP. It is also responsible for parsing EIGRP packets and informing DUAL
of the new information received. EIGRP asks DUAL to make routing decisions, but the results are
stored in the IP routing table. EIGRP is also responsible for redistributing routes learned by other
IP routing protocols.
These sections contain this configuration information:
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Note
To enable EIGRP, the switch must be running the IP services image.
Default EIGRP Configuration
shows the default EIGRP configuration.
Table 36-7
Default EIGRP Configuration
Feature
Default Setting
Auto summary
Enabled. Subprefixes are summarized to the classful network
boundary when crossing classful network boundaries.
boundary when crossing classful network boundaries.
Default-information
Exterior routes are accepted and default information is passed
between EIGRP processes when doing redistribution.
between EIGRP processes when doing redistribution.