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ntp scaling

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geert.nijs at gmail

Mar 8, 2010, 5:13 AM

Post #1 of 5 (481 views)
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ntp scaling

Hi all,

Does anyone have an idea how many devices/clients can synchronise time to a
SUP720 C6500 module ?
How does it scale ? If i point 10, 100 , 1000, ... clients to a loopback
address on the supervisor ?

regards,
Geert
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nick at inex

Mar 8, 2010, 6:08 AM

Post #2 of 5 (445 views)
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Re: ntp scaling [In reply to]

On 08/03/2010 13:13, Geert Nijs wrote:
> Does anyone have an idea how many devices/clients can synchronise time to a
> SUP720 C6500 module ?
> How does it scale ? If i point 10, 100 , 1000, ... clients to a loopback
> address on the supervisor ?

Offhand no, but why on earth would you want to use a sup720 as an NTP time
server? You can get extremely cheap off-the-shelf hardware which will do a
much better job. And, if the server gets overloaded, you can buy a second
server and anycast the NTP server address (i.e. completely linear scaling)

Nick
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alex at digriz

Mar 8, 2010, 6:47 AM

Post #3 of 5 (444 views)
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Re: ntp scaling [In reply to]

Geert Nijs <geert.nijs [at] gmail> wrote:
>
> Does anyone have an idea how many devices/clients can synchronise time to a
> SUP720 C6500 module ?
>
> How does it scale ? If i point 10, 100 , 1000, ... clients to a loopback
> address on the supervisor ?
>
We are a medium sized university and are definately in the 10->100 range
and see no problems. All our edge stacks (25 of time) plus in theory
all the servers talk to our 6500's to sync and on there we see:
----
6509-1#show processes cpu | include NTP
556 291788 5634668 51 0.00% 0.00% 0.00% 0 NTP
----

I do cheat though and we anycast the NTP address (place the same address
on our two core boxes) so the clients speak to the nearest server.

Cheers

--
Alexander Clouter
.sigmonster says: An evil mind is a great comfort.

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alex at digriz

Mar 8, 2010, 7:56 AM

Post #4 of 5 (444 views)
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Re: ntp scaling [In reply to]

Nick Hilliard <nick [at] inex> wrote:
>
> Offhand no, but why on earth would you want to use a sup720 as an NTP time
> server?
>
...because it is a box typically in the core of the network that is
probably already always available and sync'ed up to the world. No harm
in letting it distrubute the time to the servers/switches on the LAN
rather than increasing your workload in maintaining a one or two
dedicated boxes (including the juice and possible OS hassles).

Cheers

--
Alexander Clouter
.sigmonster says: "Ahead warp factor 1"
-- Captain Kirk

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KaeglerM at tessco

Mar 8, 2010, 8:12 AM

Post #5 of 5 (443 views)
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Re: ntp scaling [In reply to]

As a datapoint, I was running NTP on ~315-340 devices against a
6500/sup2a for years before upgrading to a 720. Never had a problem. I
don't even think either sup noticed. :)
-porkchop

-----Original Message-----
From: cisco-nsp-bounces [at] puck
[mailto:cisco-nsp-bounces [at] puck] On Behalf Of Geert Nijs
Sent: Monday, March 08, 2010 8:14 AM
To: cisco-nsp [at] puck
Subject: [c-nsp] ntp scaling

Hi all,

Does anyone have an idea how many devices/clients can synchronise time
to a
SUP720 C6500 module ?
How does it scale ? If i point 10, 100 , 1000, ... clients to a loopback
address on the supervisor ?

regards,
Geert
_______________________________________________
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https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/

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