And 5 for a falseticker fault protection: *"Note that four upstream time servers will protect you against only one falseticker. Using the 2n+1 algorithm, five upstreams will protect you against two falsetickers, seven will protect you against three falsetickers, etc....* *Conventional wisdom is that using at least five upstream time servers would probably be a good idea, and you may want more."*
Source: 5.3.4. Excessive Number of Upstream Time Servers <http://support.ntp.org/bin/view/Support/SelectingOffsiteNTPServers#Section_5.3.3> On Mon, May 8, 2017 at 9:49 AM Matthew Huff <[email protected]> wrote: > If you are going to have local NTP servers, you will need 3 for a quorum. > 4 for redundancy. > > > > ---- > > Matthew Huff | 1 Manhattanville Rd > > Director of Operations | Purchase, NY 10577 > > OTA Management LLC | Phone: 914-460-4039 <(914)%20460-4039> > > aim: matthewbhuff | Fax: 914-694-5669 <(914)%20694-5669> > > > > *From:* cisco-voip [mailto:[email protected]] *On Behalf > Of *Ryan Huff > *Sent:* Monday, May 8, 2017 10:42 AM > *To:* Ben Amick <[email protected]>; [email protected] > *Subject:* Re: [cisco-voip] CCX and NTP > > > > Hey Ben, > > > > This has less to do with UCCX and more to do with the lack of time > precision in Windows SNTP / NTP compared to the needs of UCOS. Yes, I know, > die hard Redmond boys and girls will say that ever since Win2003 that isn't > the case but sorry, it is. (read: > https://technet.microsoft.com/en-us/library/cc773013%28v=ws.10%29.aspx). > In fact, on page 84 (PDF page) of the latest SRND ( > http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/collab11/collab11.pdf) > Windows NTP is a flat nono for Cisco UC period. > > > > IOS routers are great but here is how I like to roll (excuse the crudeness > of the drawing, put it together this morning before coffee). I typically > use Linux servers for NTP because they are so darn useful for other > utilitarian things ..... can't count how many times just having a Linux box > on the network somewhere helped me out. > > > > [image: image001.png] > > > > = Ryan = > > > > > ------------------------------ > > *From:* cisco-voip <[email protected]> on behalf of Ben > Amick <[email protected]> > *Sent:* Monday, May 8, 2017 10:12 AM > *To:* [email protected] > *Subject:* [cisco-voip] CCX and NTP > > > > What do you guys use for NTP on your CCX hosts? I’ve been informed by TAC > that “CCX does not support Windows based NTP” so I was thinking about just > pointing NTP towards my CCM hosts – is that a valid scenario? I figure that > since CCM is pretty much authoritative on everything for CCX as it is it > wouldn’t be a problem? > > > > *Ben Amick* > > Telecom Analyst > > > > > Confidentiality Note: This message is intended for use only by the > individual or entity to which it is addressed and may contain information > that is privileged, confidential, and exempt from disclosure under > applicable law. If the reader of this message is not the intended recipient > or the employee or agent responsible for delivering the message to the > intended recipient, you are hereby notified that any dissemination, > distribution or copying of this communication is strictly prohibited. If > you have received this communication in error, please contact the sender > immediately and destroy the material in its entirety, whether electronic or > hard copy. Thank you > _______________________________________________ > cisco-voip mailing list > [email protected] > https://puck.nether.net/mailman/listinfo/cisco-voip >
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