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Cisco ASA Series CLI Configuration Guide
Chapter 1 Configuring RIP
Information About RIP
The ASA supports both RIP Version 1 and RIP Version 2. RIP Version 1 does not send the subnet mask
with the routing update. RIP Version 2 sends the subnet mask with the routing update and supports
variable-length subnet masks. Additionally, RIP Version 2 supports neighbor authentication when
routing updates are exchanged. This authentication ensures that the ASA receives reliable routing
information from a trusted source.
RIP has advantages over static routes because the initial configuration is simple, and you do not need to
update the configuration when the topology changes. The disadvantage to RIP is that there is more
network and processing overhead than in static routing.
Routing Update Process
RIP sends routing-update messages at regular intervals and when the network topology changes. When
a router receives a routing update that includes changes to an entry, it updates its routing table to reflect
the new route. The metric value for the path is increased by 1, and the sender is indicated as the next hop.
RIP routers maintain only the best route (the route with the lowest metric value) to a destination. After
updating its routing table, the router immediately begins transmitting routing updates to inform other
network routers of the change. These updates are sent independently of the regularly scheduled updates
that RIP routers send.
RIP Routing Metric
RIP uses a single routing metric (hop count) to measure the distance between the source and a destination
network. Each hop in a path from source to destination is assigned a hop count value, which is typically
1. When a router receives a routing update that contains a new or changed destination network entry, the
router adds 1 to the metric value indicated in the update and enters the network in the routing table. The
IP address of the sender is used as the next hop.
RIP Stability Features
RIP prevents routing loops from continuing indefinitely by implementing a limit on the number of hops
allowed in a path from the source to a destination. The maximum number of hops in a path is 15. If a
router receives a routing update that contains a new or changed entry, and if increasing the metric value
by 1 causes the metric to be infinity (that is, 16), the network destination is considered unreachable. The
downside of this stability feature is that it limits the maximum diameter of a RIP network to less than 16
hops.
RIP includes a number of other stability features that are common to many routing protocols. These
features are designed to provide stability despite potentially rapid changes in network topology. For
example, RIP implements the split horizon and hold-down mechanisms to prevent incorrect routing
information from being propagated.
RIP Timers
RIP uses numerous timers to regulate its performance. These include a routing-update timer, a
route-timeout timer, and a route-flush timer. The routing-update timer clocks the interval between
periodic routing updates. Generally, it is set to 30 seconds, with a small random amount of time added
whenever the timer is reset. This is done to help prevent congestion, which could result from all routers
Содержание 5505 - ASA Firewall Edition Bundle
Страница 28: ...Glossary GL 24 Cisco ASA Series CLI Configuration Guide ...
Страница 61: ...P A R T 1 Getting Started with the ASA ...
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Страница 218: ...1 56 Cisco ASA Series CLI Configuration Guide Chapter 1 Managing Feature Licenses Feature History for Licensing ...
Страница 219: ...P A R T 2 Configuring High Availability and Scalability ...
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Страница 358: ...1 22 Cisco ASA Series CLI Configuration Guide Chapter 1 Information About Failover Failover Messages ...
Страница 403: ...P A R T 2 Configuring Interfaces ...
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Страница 499: ...P A R T 2 Configuring Basic Settings ...
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Страница 516: ...1 16 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Basic Settings Monitoring DNS Cache ...
Страница 533: ...P A R T 2 Configuring Objects and Access Lists ...
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Страница 558: ...1 4 Cisco ASA Series CLI Configuration Guide Chapter 1 Information About Access Lists Where to Go Next ...
Страница 601: ...P A R T 2 Configuring IP Routing ...
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Страница 632: ...1 8 Cisco ASA Series CLI Configuration Guide Chapter 1 Defining Route Maps Feature History for Route Maps ...
Страница 680: ...1 48 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring OSPF Feature History for OSPF ...
Страница 745: ...P A R T 2 Configuring Network Address Translation ...
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Страница 780: ...1 34 Cisco ASA Series CLI Configuration Guide Chapter 1 Information About NAT Where to Go Next ...
Страница 844: ...1 32 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Twice NAT Feature History for Twice NAT ...
Страница 845: ...P A R T 2 Configuring AAA Servers and the Local Database ...
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Страница 859: ...1 13 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring AAA Servers and the Local Database Configuring AAA ...
Страница 871: ...1 25 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring AAA Servers and the Local Database Configuring AAA ...
Страница 981: ...P A R T 2 Configuring Access Control ...
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Страница 994: ...1 12 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Access Rules Feature History for Access Rules ...
Страница 1028: ...1 34 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Management Access Feature History for Management Access ...
Страница 1054: ...1 26 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring AAA Rules for Network Access Feature History for AAA Rules ...
Страница 1060: ...1 6 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Web Cache Services Using WCCP Feature History for WCCP ...
Страница 1061: ...P A R T 2 Configuring Service Policies Using the Modular Policy Framework ...
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Страница 1093: ...P A R T 2 Configuring Application Inspection ...
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Страница 1191: ...P A R T 2 Configuring Unified Communications ...
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Страница 1333: ...P A R T 2 Configuring Connection Settings and QoS ...
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Страница 1370: ...1 20 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring QoS Feature History for QoS ...
Страница 1379: ...P A R T 2 Configuring Advanced Network Protection ...
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Страница 1448: ...1 20 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Threat Detection Configuration Examples for Threat Detection ...
Страница 1474: ...1 18 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Filtering Services Monitoring Filtering Statistics ...
Страница 1475: ...P A R T 2 Configuring Modules ...
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Страница 1504: ...1 28 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring the ASA IPS Module Feature History for the ASA IPS module ...
Страница 1528: ...1 24 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring the ASA CX Module Feature History for the ASA CX Module ...
Страница 1548: ...1 20 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring the ASA CSC Module Feature History for the CSC SSM ...
Страница 1549: ...P A R T 2 Configuring VPN ...
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Страница 1592: ...1 42 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring IPsec and ISAKMP Supporting the Nokia VPN Client ...
Страница 1612: ...1 20 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring L2TP over IPsec Feature History for L2TP over IPsec ...
Страница 1796: ...1 6 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring the PPPoE Client Using Related Commands ...
Страница 1965: ...P A R T 2 Configuring Logging SNMP and Smart Call Home ...
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Страница 1988: ...1 22 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Logging Feature History for Logging ...
Страница 2002: ...1 14 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring NetFlow Secure Event Logging NSEL Feature History for NSEL ...
Страница 2036: ...1 34 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring SNMP Feature History for SNMP ...
Страница 2059: ...P A R T 2 System Administration ...
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Страница 2098: ...1 8 Cisco ASA Series CLI Configuration Guide Chapter 1 Troubleshooting Viewing the Coredump ...
Страница 2099: ...P A R T 2 Reference ...
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