Redundant DHCP/TFTP Services

[megaco]

Has anyone done anything with redundant DHCP services?

Can this work with redundant TFTP services? Do I need to go the Enterprise Route?

Thanks in advance..

 

[NERIC]

DHCP redundancy doesn't seem to be much of an issue. At least not for us. Phones are configured using MAC addresses. A good measure would be to set a long lease time. tyipcally, the DHCP server is loaded on the call manager anyway. So, if you lose DHCP, you may have bigger issues to deal with. It might be wise to set up DHCP on one of the routers as a backup and leave it down unless there's a need for it. We run SRST on the routers also. This allows for limitted functionality in the event of a server outage.

 

[computerhighguy]

We have a seperate DHCP server for our voice vlan. Basically I used a Cisco switch to act as the DHCP server. You could easily add a second DHCP server (with a different range of IP addresses) to another switch and that would give you redundancy for your DHCP server.

You can specify multiple server in the option 150 of the DHCP server. So yes, you can have redundant TFTP servers also.

HOWEVER!!!

If you have a good quality install for your operating system and you don't have a substantial amount of phones, you probably won't have much to worry about. If the phones don't boot all the way, you know where the problem lies. I use the 7935 model for my CCM servers and with the RAID subsystem, I doubt they will crash (it has my TFTP server on it).


It is what it is!!
__________________________________
A+, Net+, I-Net+, Certified Web Master, MCP, MCSA, MCSE, CCNA, CCDA, and few others (I got bored one day)

 

[BuckWeet]

DHCP running on the callmanagers!!! umm unless they've changed it, that is not supported..

 

[computerhighguy]

ummm... right. Do you seriously think that Cisco won't support DHCP from their routers and switches?




It is what it is!!
__________________________________
A+, Net+, I-Net+, Certified Web Master, MCP, MCSA, MCSE, CCNA, CCDA, and few others (I got bored one day)

 

[BuckWeet]

did you read anything in this posting at all?? i think not..

because i'm not commenting on what you say, i'm commenting on what NERIC said..

he says to run DHCP on the callmanagers..


running it on the switches/routers is supported..


BuckWeet

 

[computerhighguy]

Yeah... my bad. I'll be quiet now.

(computerhighguy ducks away cause he can't read)





It is what it is!!
__________________________________
A+, Net+, I-Net+, Certified Web Master, MCP, MCSA, MCSE, CCNA, CCDA, and few others (I got bored one day)

 

[congogrey]

I have done both redundant DHCP (sort of) and redundant TFTP. For the DHCP I have split the scope across two or more DHCP servers (each one with half of the scope).

To have fully redundnat DHCP you will need to use something like Cisco Network Registrar for fully redundnat DHCP.

The TFTP is easy...using option 150 in your DHCP scope you can define the option as an array and put each of your CCM's in the list and the phones will then be aware of each TFTP server instance.

"For every complex problem, there is a solution that is simple, neat and wrong" -- H.L. Mencken

 

[BuckWeet]

I think with win2k3 the clustering services are there in the normal server edition, so you can do the dhcp redundancy..


BuckWeet

 

[AdmanOK]

I have a central DHCP server for all my remote sites using an 'ip helper-address' on a Cisco router out at the site. This works fine until the WAN drops out and nothing can get an IP address anymore. I wish there was some way in IOS that I could say ip helper over to 10.x.x.x, but if you don't get a response back to broadcast within x seconds then use an address from this local pool... would save many headaches. I have to have centralized DHCP for dynamic DNS registration of non windows devices.

 

[Wavesg]

DHCP on Call Manager not supported by cisco??? Where did you get that? Are you saying that you need a separe box to run DHCP. Why can't the publisher run it.

Stay cool; it’s not over yet!

 

[BuckWeet]

It is not supported on running on the callmanager servers, unless they have changed it recently..

The main reason, is because those servers are tehre to be processing IPT requests, not to process dhcp requests and such.. Its an application server for a specific set of applications, not a multi-purpose server just to run anything and everything on.

Can it do it? sure..


BuckWeet

 

[MG2005]

Typically, DHCP should be configured to run on a standalone server because a large number of devices requesting DHCP configuration could cause high CPU and memory usage, which can impact server performance. Therefore, you should not run DHCP on a Cisco CallManager server. In some instances, given a small Cisco CallManager deployment with no more than 1000 devices registering to the cluster, you may run DHCP on a Cisco CallManager server; however, if the server experiences high CPU load, you should move DHCP to a standalone server. If more than 1000 devices are registered to the cluster, DHCP must be run on a standalone server."