5.1 R3 is sending 2 types of Hellos


The default hold time is three times the hello interval, or 15 seconds.

For slow-speed NBMA networks, the default hold time is 180 seconds.

This is because FR cloud is served by the ISP.

It is not our own property.

If we send so many Hellos through the cloud, it costs us a lot.

This is the reason why we sustain so many Hellos compared with non NBMA networks.


I presume?


  • NBMA is the slowest WAN link & it has limited bandwidth with large delay. So, if the interval for hello & delay are as fast as the broadcast & point-to-point link, it may not be consistent due to the delay & route flap will occur, that's why we have slower hello & dead interval than other media types.


    Thanks, Hari.


    My mistake, no reason of the cost effective.


    NBMA networks sound primitive.

    It is the slowest WAN link, limited bandwidth with large delay.

    But no choice but to utilize this system.

    Just like we are pulling our punches to weak opponent.


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