[cisco-voip] DHCP Migration Strategy - RFC

Wes Sisk wsisk at cisco.com
Fri Sep 18 10:13:37 EDT 2009


that is correct, phones reboot if IP changes.

most dhcp servers will not NAK a renew request. This was implemented to 
facilitate redudant DHCP servers for an address scope.  Since DHCP 
servers will not NAK your client leases have to expire before they will 
get a new address.

/wes

On Thursday, September 17, 2009 5:44:11 PM, Scott Voll 
<svoll.voip at gmail.com> wrote:
> It's been a really long time ago, but has anyone had issue with short 
> lease times.  Doesn't the phone blip every time it gets a new IP?  IF 
> memory serves me correct I had calls cutting out when the phones 
> grabbed a new IP.  Was that just a Firmware load I had at the time?
>
> Scott
>
> On Thu, Sep 17, 2009 at 2:39 PM, Lelio Fulgenzi <lelio at uoguelph.ca 
> <mailto:lelio at uoguelph.ca>> wrote:
>
>     sweet! thanks.
>
>
>     ---
>     Lelio Fulgenzi, B.A.
>     Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1
>     (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
>     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>     "Bad grammar makes me [sic]" - Tshirt
>
>
>     ----- Original Message -----
>     From: "Matthew Loraditch" <MLoraditch at heliontechnologies.com
>     <mailto:MLoraditch at heliontechnologies.com>>
>     To: "Lelio Fulgenzi" <lelio at uoguelph.ca <mailto:lelio at uoguelph.ca>>
>     Cc: "cisco-voip voyp list" <cisco-voip at puck.nether.net
>     <mailto:cisco-voip at puck.nether.net>>, "Jason Fuermann"
>     <JBF005 at shsu.edu <mailto:JBF005 at shsu.edu>>
>     Sent: Thursday, September 17, 2009 5:36:34 PM GMT -05:00 US/Canada
>     Eastern
>     Subject: RE: [cisco-voip] DHCP Migration Strategy - RFC
>
>     Go Google: http://www.infoblox.com/import/
>
>     I just look at the parts of the wizard I could get to w/o an
>     infoblox and it says you can, albeit looks like you have to do the
>     whole server from the included instructions not sure if that would
>     mess you up or not
>
>      
>
>      
>
>     *Matthew Loraditch*
>     1965 Greenspring Drive
>
>     Timonium, MD 21093
>     support at heliontechnologies.com <mailto:support at heliontechnologies.com>
>     (p) (410) 252-8830
>     (F) (443) 541-1593
>
>     Visit us at www.heliontechnologies.com
>     <http://www.heliontechnologies.com>
>     Support Issue? Email support at heliontechnologies.com
>     <mailto:support at heliontechnologies.com> for fast assistance!
>
>      
>
>     *From:* Lelio Fulgenzi [mailto:lelio at uoguelph.ca
>     <mailto:lelio at uoguelph.ca>]
>     *Sent:* Thursday, September 17, 2009 5:32 PM
>     *To:* Matthew Loraditch
>     *Cc:* cisco-voip voyp list; Jason Fuermann
>     *Subject:* Re: [cisco-voip] DHCP Migration Strategy - RFC
>
>      
>
>     Central DHCP server is InfoBlox. I'll have to see if they can
>     import a Windows DHCP export file.
>
>     ---
>     Lelio Fulgenzi, B.A.
>     Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1
>     (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
>     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>     "Bad grammar makes me [sic]" - Tshirt
>
>
>     ----- Original Message -----
>     From: "Matthew Loraditch" <MLoraditch at heliontechnologies.com
>     <mailto:MLoraditch at heliontechnologies.com>>
>     To: "Lelio Fulgenzi" <lelio at uoguelph.ca
>     <mailto:lelio at uoguelph.ca>>, "Jason Fuermann" <JBF005 at shsu.edu
>     <mailto:JBF005 at shsu.edu>>
>     Cc: "cisco-voip voyp list" <cisco-voip at puck.nether.net
>     <mailto:cisco-voip at puck.nether.net>>
>     Sent: Thursday, September 17, 2009 5:27:51 PM GMT -05:00 US/Canada
>     Eastern
>     Subject: RE: [cisco-voip] DHCP Migration Strategy - RFC
>
>     Is your central DHCP server windows as well? If so you can migrate
>     the Scope, I’ve done it many times, shut down current dhcp server,
>     export to file, copy file to new server, import and activate it
>     and update ip helper,  can be done in 5 to 10 minutes.  all
>     current leases and all other settings related to the scope come
>     over. You can do it scope by scope or the whole server at the same
>     time.
>
>      
>
>      
>
>     *Matthew Loraditch*
>     1965 Greenspring Drive
>
>     Timonium, MD 21093
>     support at heliontechnologies.com <mailto:support at heliontechnologies.com>
>     (p) (410) 252-8830
>     (F) (443) 541-1593
>
>     Visit us at www.heliontechnologies.com
>     <http://www.heliontechnologies.com>
>     Support Issue? Email support at heliontechnologies.com
>     <mailto:support at heliontechnologies.com> for fast assistance!
>
>      
>
>     *From:* cisco-voip-bounces at puck.nether.net
>     <mailto:cisco-voip-bounces at puck.nether.net>
>     [mailto:cisco-voip-bounces at puck.nether.net
>     <mailto:cisco-voip-bounces at puck.nether.net>] *On Behalf Of *Lelio
>     Fulgenzi
>     *Sent:* Thursday, September 17, 2009 5:23 PM
>     *To:* Jason Fuermann
>     *Cc:* cisco-voip voyp list
>     *Subject:* Re: [cisco-voip] DHCP Migration Strategy - RFC
>
>      
>
>     Good catch - I'll see if the new server can do a ping or something
>     first, and what ACLs we have to open to allow that.
>
>     ---
>     Lelio Fulgenzi, B.A.
>     Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1
>     (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
>     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>     "Bad grammar makes me [sic]" - Tshirt
>
>
>     ----- Original Message -----
>     From: "Jason Fuermann" <JBF005 at shsu.edu <mailto:JBF005 at shsu.edu>>
>     To: "Wes Sisk" <wsisk at cisco.com <mailto:wsisk at cisco.com>>, "Lelio
>     Fulgenzi" <lelio at uoguelph.ca <mailto:lelio at uoguelph.ca>>
>     Cc: "cisco-voip voyp list" <cisco-voip at puck.nether.net
>     <mailto:cisco-voip at puck.nether.net>>
>     Sent: Thursday, September 17, 2009 5:18:35 PM GMT -05:00 US/Canada
>     Eastern
>     Subject: RE: [cisco-voip] DHCP Migration Strategy - RFC
>
>     If I remember correctly we’ve had leases set to 30 minutes before
>     without any issues. I wouldn’t go below that because the phone is
>     going to be renewing at a 15 minute interval. I’d check on what
>     DHCP server you’re using, some will check if an address is in use
>     before issuing one (at least I’ve experienced that on windows
>     DHCP), and on that same note, make sure there is enough overlap in
>     the scopes so you don’t run out of leases due to addresses being
>     blocked for conflicts.
>
>      
>
>     *From:* cisco-voip-bounces at puck.nether.net
>     <mailto:cisco-voip-bounces at puck.nether.net>
>     [mailto:cisco-voip-bounces at puck.nether.net
>     <mailto:cisco-voip-bounces at puck.nether.net>] *On Behalf Of *Wes Sisk
>     *Sent:* Thursday, September 17, 2009 4:03 PM
>     *To:* Lelio Fulgenzi
>     *Cc:* cisco-voip voyp list
>     *Subject:* Re: [cisco-voip] DHCP Migration Strategy - RFC
>
>      
>
>     depending on your nw topology this could still be a problem:
>     CSCso60222    After DHCP Monitor service is stopped, IP is given
>     to DHCP clients
>
>     make sure DHCP DISCOVER (and renew as a subset of DISC) will not
>     reach the CM server.
>
>     Phones tend to go haywire when lease duration goes below something
>     like 5 minutes so I would stay very clear of that on the order of
>     1 hour.  I don't have the bug for that handy.
>
>     /Wes
>
>     On Thursday, September 17, 2009 4:51:28 PM, Lelio Fulgenzi
>     <lelio at uoguelph.ca> <mailto:lelio at uoguelph.ca> wrote:
>
>     So, I'm planning on moving the DHCP service off a CallManager
>     subscriber to our central DHCP service. Past experience tells me
>     that this shouldn't be too much of an issue, but there are some
>     things to look out for. For example, IP address conflicts on
>     phones causes both phones to reset.
>
>     Here's what I'm planning on doing (testing out on one scope to
>     begin with):
>
>        1. Lower lease time on CallManager subscriber DHCP server from
>           8 days to 1 hour. Wait until all phones have a 1 hour lease.
>        2. Change IP helper address on interface to new DHCP server.
>        3. Deactivate scope on CallManager subscriber DHCP server.
>        4. Wait one hour until all phones have new lease on new DHCP
>           server and all IP address conflicts are resolved.
>        5. Remotely reset phones that are not co-operating.
>
>     Two questions:
>
>         * Is having a 1 hour lease time on the subscriber an issue?
>           It's a 7835 from about 4 years ago and it does nothing else
>           other than DHCP/TFTP.
>         * Can I go a step further and lower the lease time to 30min or
>           even 15 min without significant concern?
>
>     We have about 7500 phones.
>     ---
>     Lelio Fulgenzi, B.A.
>     Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1
>     (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
>     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>     "Bad grammar makes me [sic]" - Tshirt
>
>      
>
>      
>
>      
>
>
>
>     ------------------------------------------------------------------------
>
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>
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>
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