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backup tftp server

Unanswered Question
thisisshanky Thu, 09/25/2003 - 18:47
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You dont need to setup really a redundant TFTP server. If you have a pub and a sub, the sub will be the active CCM which routes the calls between phones. The Pub should be configured as the backup. In this case, its better to configure the pub as the active TFTP server IP address. The advantage of making the pub as the active TFTP server is that, when subscriber fails, the pub is still available as the fallback server to route calls, as well as handle TFTP downloads.) (Assuming, The probability of a subscriber failure is less likely)

jasyoung Thu, 09/25/2003 - 19:32
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Make sure that TFTP services are started on all machines in the cluster (they are by default). After that, all you need to do is specify multiple TFTP servers in option 150 from your DHCP server. From a Microsoft DHCP server, make sure you have the 'Array' checkbox checked to enable entry of multiple addresses.

I don't recall offhand what the "official" recommendations are on splitting up services on a two-server cluster is, but I personally run all services on both boxes to provide redundancy and service through upgrades.

Here in reality-land, you don't have box or service failures all that often but you do go through service packs and OS patches like crazy. So you need to be able to survive taking a cluster member out of service for some time without functionality loss. The multiple TFTP server option helps because sometimes you make changes during upgrades, like updating phone loads, that require you have TFTP services up and running even if you've got your primary TFTP server down. I'm also told that the CCM 3.3 phone loads are supposed to be able to accept multiple A records returned on a DNS query for their Services and Directory button URLs and try the other hosts if one of them refuses a connection.


Thanks for your answer. I still got two questions here:

1. I usually user option 66 as tftp. How can I add 150 since it's not in the list.

2.Where is the "array" checkbox?I couldn't see it.

3.DId you notice if you go to the phone configuration from the phone, you actually only can see one TFTP server. So even if we are able to enable couple tftp server in the DHCP server, it still not show up on the phone configuration.


jasyoung Mon, 09/29/2003 - 10:50
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It's recommended that you use option 150. Option 150 needs to be added in a special way the first time you use it on that DHCP server. See the following document for how you define it:


In particular see step 11, where it shows you how to add the option, and step 12, where you see how to define it as an Array (turn on the checkbox) of IP addresses.

"TFTP Server 2" is there on all modern phone loads. What may confuse you is that it's not next to TFTP Server 1, because I guess they didn't want to renumber the existing list items when TFTP Server 2 was added. It's way down at line 42 on the phone's Network Configuration screen, as opposed to line 8 for TFTP Server 1.


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