Maximum Time difference between DHCP primary and DHCP failover Server

Thomas Markwalder tmark at isc.org
Tue Jan 19 13:05:38 UTC 2021


Excuse the typo "least update" should be "lease update"

On 1/19/21 8:03 AM, Thomas Markwalder wrote:
> This is going to vary largely on site dynamics. The primary challenge 
> to failover performance, is that it is a synchronous protocol. Servers 
> are supposed to wait until their peers acknowledge that a least update 
> has been received prior to sending the corresponding response (i.e. 
> DHCPACK) to the client.
>
> In other words, this adds the round trip latency to the response time 
> for a given client's DHCPREQUEST.  If DHCPREQUESTs are coming in too 
> fast, the server will fall behind and clients will stop getting 
> responses. If you need as sustained 10 DORAs a second, then 250ms 
> round-trip latency between the peers is going to be a deal breaker.
>
> I'm sure others on this list will have plenty to share on the subject.
>
>
> On 1/19/21 6:38 AM, kraishak wrote:
>> Hi Thomas,
>>
>> Thanks for sharing information, Can you also please comment or share 
>> your
>> experience if you have any, about what could be the maximum network 
>> latency
>> between the primary and failover DHCP servers that does not impact the
>> server performance
>>
>> Thanks in advance
>> Kraishak
>>
>>
>>
>> -- 
>> Sent from: http://isc-dhcp-users.2343191.n4.nabble.com/
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