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Cisco ASA Series CLI Configuration Guide
Chapter 1 Configuring EIGRP
Licensing Requirements for EIGRP
The hello packets are sent out as multicast messages. No response is expected to a hello message. The
exception to this is for statically defined neighbors. If you use the
neighbor
command, or configure the
Hello Interval in ASDM, to configure a neighbor, the hello messages sent to that neighbor are sent as
unicast messages. Routing updates and acknowledgements are sent out as unicast messages.
Once this neighbor relationship is established, routing updates are not exchanged unless there is a change
in the network topology. The neighbor relationship is maintained through the hello packets. Each hello
packet received from a neighbor includes a hold time. This is the time in which the ASA can expect to
receive a hello packet from that neighbor. If the ASA does not receive a hello packet from that neighbor
within the hold time advertised by that neighbor, the ASA considers that neighbor to be unavailable.
The EIGRP protocol uses four key algorithm technologies, four key technologies, including neighbor
discovery/recovery, Reliable Transport Protocol (RTP), and DUAL, which is important for route
computations. DUAL saves all routes to a destination in the topology table, not just the least-cost route.
The least-cost route is inserted into the routing table. The other routes remain in the topology table. If
the main route fails, another route is chosen from the feasible successors. A successor is a neighboring
router used for packet forwarding that has a least-cost path to a destination. The feasibility calculation
guarantees that the path is not part of a routing loop.
If a feasible successor is not found in the topology table, a route recomputation must occur. During route
recomputation, DUAL queries the EIGRP neighbors for a route, who in turn query their neighbors.
Routers that do no have a feasible successor for the route return an unreachable message.
During route recomputation, DUAL marks the route as active. By default, the ASA waits for three
minutes to receive a response from its neighbors. If the ASA does not receive a response from a neighbor,
the route is marked as stuck-in-active. All routes in the topology table that point to the unresponsive
neighbor as a feasibility successor are removed.
Note
EIGRP neighbor relationships are not supported through the IPsec tunnel without a GRE tunnel.
Using Clustering
For information about using clustering with EIGRP, see the
“Dynamic Routing and Clustering” section
.
Licensing Requirements for EIGRP
The following table shows the licensing requirements for this feature:
Model
License Requirement
All models
Base License.
Summary of Contents for 5505 - ASA Firewall Edition Bundle
Page 28: ...Glossary GL 24 Cisco ASA Series CLI Configuration Guide ...
Page 61: ...P A R T 1 Getting Started with the ASA ...
Page 62: ......
Page 219: ...P A R T 2 Configuring High Availability and Scalability ...
Page 220: ......
Page 403: ...P A R T 2 Configuring Interfaces ...
Page 404: ......
Page 499: ...P A R T 2 Configuring Basic Settings ...
Page 500: ......
Page 533: ...P A R T 2 Configuring Objects and Access Lists ...
Page 534: ......
Page 601: ...P A R T 2 Configuring IP Routing ...
Page 602: ......
Page 745: ...P A R T 2 Configuring Network Address Translation ...
Page 746: ......
Page 845: ...P A R T 2 Configuring AAA Servers and the Local Database ...
Page 846: ......
Page 981: ...P A R T 2 Configuring Access Control ...
Page 982: ......
Page 1061: ...P A R T 2 Configuring Service Policies Using the Modular Policy Framework ...
Page 1062: ......
Page 1093: ...P A R T 2 Configuring Application Inspection ...
Page 1094: ......
Page 1191: ...P A R T 2 Configuring Unified Communications ...
Page 1192: ......
Page 1333: ...P A R T 2 Configuring Connection Settings and QoS ...
Page 1334: ......
Page 1379: ...P A R T 2 Configuring Advanced Network Protection ...
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Page 1475: ...P A R T 2 Configuring Modules ...
Page 1476: ......
Page 1549: ...P A R T 2 Configuring VPN ...
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Page 1965: ...P A R T 2 Configuring Logging SNMP and Smart Call Home ...
Page 1966: ......
Page 2059: ...P A R T 2 System Administration ...
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Page 2098: ...1 8 Cisco ASA Series CLI Configuration Guide Chapter 1 Troubleshooting Viewing the Coredump ...
Page 2099: ...P A R T 2 Reference ...
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