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  1. Hi William,

    Under topology base you will find commands that have to do with the EIGRP topology table. Stuff like redistribution, filtering, etc. Here’s an overview of all commands:

    R1(config-router)#router eigrp TEST                               
    R1(config-router)#address-family ipv4 unicast autonomous-system 1 
    R1(config-router-af)#topology base                                  
    Address Family Topology configuration commands:
      auto-summary         Enable automatic network number summarization
      cts                  EIGRP Trustsec Configuration
      default              Set a command to its defaults
      default-information  Control distribution of default information
      default-metric       Set metric of redistributed routes
      distance             Define an administrative distance
      distribute-list      Filter entries in eigrp updates
      eigrp                EIGRP specific commands
      exit-af-topology     Exit from Address Family Topology configuration mode
      maximum-paths        Forward packets over multiple paths
      metric               Modify metrics and parameters for advertisement
      no                   Negate a command or set its defaults
      offset-list          Add or subtract offset from EIGRP metrics
      redistribute         Redistribute IPv4 routes from another routing protocol
      snmp                 Modify snmp parameters
      summary-metric       Specify summary to apply metric/filtering
      timers               Adjust topology specific timers
      topo-interface       Enter Topology interface configuration
      traffic-share        How to compute traffic share over alternate paths
      variance             Control load balancing variance


  2. Hi Minh,

    Address-families are used for different protocols. For example, in EIGRP there is an address-family for IPv4 and another address-family for IPv6.

    For BGP, there are address families for unicast, multicast, VPN routes and each of those for both IPv4 and IPv6.

    The service family for EIGRP is used for SAF (Service Advertisement Framework). SAF is some framework that is used for Voice over IP. Instead of IPv4/IPv6, you can exchange SAF stuff with EIGRP .


  3. Hi Lagapides ,

    Thanks …Well understand this explanation…

  4. Hello Network

    EIGRP named mode supports what is known as the Wide Metrics feature. This feature supports 64-bit metric calculations as opposed to EIGRP classic mode that use 32-bit calculations. This results in varying metric values between the two.

    Wide metrics was introduced in order to accommodate high-bandwidth interfaces and Ethernet channels. The increase in available speeds has resulted in incorrect or inconsistent routing behavior with the classic EIGRP routing metrics. The lowest delay that can be configured for an interface is 10 microseconds. As a result, interfaces with speeds of 10 Gbps or more including channeld interfaces will appear to EIGRP as a single GE interface. For this reason, the 64 bit metric calculation has been introduced resulting in different metric values. More on this can be found here:

    The new 64 bit metric calculations are designed to be backward compatible with classic EIGRP. However, sometimes scaling can be an issue. More on this can be found below.

    I hope this has been helpful!


  5. Hi Rene and staff

    i just look at EIGRP named to configure a lab in another lesson
    So i explore the commands of the configuration modes; in the labs i did, i only used the topology mode base
    I tried to test (just for fun) the command with EIGRP that i suppose to set Multi-Topology Routing

    As you see, IOS answer “VIDEO does not exist”
    Could you give me some explanation where i can set a topology that is not the topology base ?

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