multi interfaces(vlans) configuration

glenn.satchell at glenn.satchell at
Thu Oct 8 07:53:53 UTC 2020


The size of the server depends on two things - the number of clients and 
how often they renew their lease.

Eg if they renew once every hour versus once every day then that takes 
24 times as much cpu reources in the work done to renew the leases and 
record the updates.

Secondly a large amount of the lease data is kept in memory, so the 
number of lease affects the memory size.

So, how many sites? You say 500 vlans - which I guess equates to subnets 
- that's what dhcpd configuration needs. And how many devices per subnet 
typically? A subnet doesn't have to be a /24, it can be any size that is 
suitable for that subnet, eg multiple /24 pools, /21 will give 2048 
addresses, /20 will give 4096, or bigger if needed.

Others running large number of clients, say 10-20k can probably offer 
better advice, but I don't think a PI4 with 8GB is not going to have 
enough memory, cpu or storage I/O.

You'll probably want a server with 32 or 64GB memory and SSD or NVME 
disks for high throughput. With that many clients then 10 or 25 Gigabit 
network is probably needed too.

You'll also need to think about what bandwidth you have in your 
back-haul networks back to the central network where the dhcp server is.

However, a PI4 is cheap so you could try one out to see how it goes.


On 2020-10-08 15:57, ahiya wrote:
> I'm new to isc/kea.I have multi-sites with around 2000-5000 devices per
> site.the real issue is that they are spread across 500 different 
> wanted to know is isc/kea is the right solution for that task.and what 
> is
> the right way to implement it?if the only service I need is dhcp4 
> serving
> all these segments, what will be the HW requirements for this task?
> Raspberry PI4 with 8G mem will be enough?should I use .conf files or 
> should
> I go for the backend server?ill appreciate any feedback.thanks a lot.
> --
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