TFTP - Ticket Opened with Tech Support

[danramirez]

Hi, I just opened a ticket with Tech Central, I just like to share it with you guys, I would appreciate your comments as well.

Be patient, it's a long story...

We recently networked two PBXs together as “Cluster” and then programmed some phones to be resilient on the mate controller.

Note that PBXs are in different subnets, different Vlans, but there’s one common DHCP server that provides Options to many scopes. (Scopes are: DataA Vlan, DataB Vlan, PBXA Vlan, and PBXB Vlan).

DHCP is an MSL Server with four SCOPES; note we are using Option 125 for Mitel Phones.

Also each PBX is being used as TFTP server for its phones.
Ports on switch are Tagged to correspondent Voice Vlan and UNTagged to Data Vlan, L3 Switch forwards DHCP/BootP broadcasts to IP Address of DHCP Server (DHCP Helper).

DHCP Scope for PBXA Vlan has got IP Address of “PBXA” Controller, then IP address of “PBXB” Controller separated by a “,” (Call server address: 172.16.10.10,172.16.20.10), and also these same addresses for TFTP (TFTP server address: 172.16.10.10,172.16.20.10).

DHCP Scope for PBXB Vlan has got IP Address of “PBXB” Controller, then IP address of “PBXA” Controller separated by a “,” as well. (Call server address 172.16.20.10,172.16.10.10) , and also these same addresses for TFTP (TFTP server address: 172.16.20.10,172.16.10.10).

Note that: When entering into debug mode on the phone, (Vol UP, Vol DWN, CFG…) I see: Current Controller, ICP1, ICP2, BUT ONLY ONE TFTP SERVER, Phone is 5312. I don’t see the second IP address of TFTP.

Resilient phones are programmed to have a secondary controller.
I have made an effort to program everything according to “the book”, Resiliency Guidelines, Help online, etc.

Up to this point almost everything works fine.

A phone that is registered to controller A nicely registers to secondary controller when PBXA is disconnected from the network, and then it rehomes back to controller A when it’s back connected to the network.

Resiliency also works fine when somebody on PBXB loses its home controller.

Now, here is where we have a problem:

If a phone which home element is PBXA, loses its controller (i.e PBXA is disconnected form the network) the phone will register on its secondary controller with no problem. But now, if that same phone is unplugged from the network while its home controller is out of service, and then the phone is plugged back in to the network, the phone will not boot up.

I think that the phone will receive options from DHCP server and will be asked to look for ICP1, or ICP2, but also to look for TFTP server on ICP1 (PBXA). At this point TFTP server on PBXA is not available as PBX is not connected to the network.

The phone doesn’t seem to get secondary TFTP server information, and that’s probably why it’s not booting up.

I have resolved this by setting only one external TFTP server (Only one TFTP server for both PBXs) and setting the DHCP Server to provide TFTP information. Option 125 for all DHCP scopes will point to TFTP server address: 172.16.20.4 (The External TFTP Server).

Questions:

1. Is this the way to do this? Do I need External TFTP servers when implementing resiliency?
2. If the answer to 1. is YES, where do I download TFTP files from? –I can’t find those on MOL. By now I had to get all the files from one of the 3300 controllers (/sysro/tftp) and load them on the external TFTP Server (solarwinds).
3. Any TFTP server that Mitel recommends for this purpose.
4. The customer surely will ask that they need TFTP redundancy, how is this achive? Should we leave this to the IT guys?

Please let me know if I’m doing something wrong or I’m missing some programming, maybe there’s a way to tell the phone to look for an alternative TFTP server in case its primary is not available.

Regards,

 

[danramirez]

...forgot to include: PBXs are, vMCD5.0 and MXe MCD5.0

 

[boycey9]

All is explained in the 3300 resiliency guidelines, See TFTP extract below.

The TFTP server is used to provide the application code to the IP Phones. There is an internal
TFTP server within the MCD system. An external TFTP server can also be used. For a larger
system it is suggested that having a central TFTP server would be of benefit in reducing
administration, especially when upgrades or changes are needed. The more dedicated TFTP
server also has the advantage of potentially providing increased number of accesses and so
the overall system will boot quicker than using the on board TFTP server.
Whether the internal, or an external, TFTP server is used, it will be necessary to ensure that
the same application code and version are used for both the primary and secondary servers.
This will ensure that there are no compatibility issues when the phones transition from their
primary to secondary ICPs. Should there be a difference in the software versions and the ICP
requires new code to be downloaded, it will override the DHCP option and force the phone to
reboot after loading new code.
The entry in the appropriate DHCP Server should identify the associated TFTP server. So
where the information in the scopes between the primary and secondary DHCP servers are
virtually identical, this is where they differ. Thus, the primary DHCP should reference the primary
TFTP server, and the secondary DHCP should reference the secondary TFTP server. In this
way if the DHCP server and TFTP server are linked and they fail, new devices will be directed
to the secondary DHCP and hence secondary TFTP server.
There is one snag to consider though. If the TFTP server is independent of DHCP and fails,
any new phones will not be able to obtain their application code and hence will not be brought
into service. Phones that are already operational and maintain an/their IP address will not be
required to re-boot and hence will not require access to the TFTP server.

 

[danramirez]

boycey,

In case I choose the option of having an externat TFTP server, where do I download all files from? Do I need to get them from one of the controller via FTP? or can I download from MOL, where?

Thanks for the text you posted,

Regards,

 

[Mitel100]

Option 125 only supports 1 TFTP address. This is why you are only seeing one within the phone debug.

__________________________

There is no 'I' in 'Team'
__________________________

 

[boycey9]

I would get them from the controller to ensure the same versions. I have never seen a full download on MOL only updates for problem loads.

mitel100 - Although I know you are correct on that it is unfortunate that the mitel does allow you to enter multiple addresses separated by commas in option 125, Just to confuse matters...lol

 

[danramirez]

That would solve a lot of things... having two IPs for TFTP

 

[LoopyLou]

When you create Option 125 does it have to be global? If it could be applied to a subnet could you then not assign a different TFTP server to different subnets ( scopes )?

I'd tell you a UDP joke but I'm afraid you won't get it. TCP jokes are the best because you always get them.

 

[danramirez]

Definetly Loopy,

When you do DHCP by subnet you can assign different IPs for TFTP, but only ONE IP at a time/per subnet.

Not like the ICP where you can enter two IPs, ICP1 and ICP2.

Regards,