Re: NTP on C2950 if you can help

MUHAMMAD SHAHEEN · ‎05-28-2003

Hi All,

I have read about NTP on Cisco link but I cannnot get it working on C2950's under the following setup.

I have 4 X C2950 connected to each other using Fibre Trunks. This is a dedicated LAN for CCTV. This particular LAN segment is independant and there is no other Layer 3 device. I am having problem to get NTP working. I have been trying to setup 2 or 3 of them as peer and point them to each other as I kbow they cannot be configured as NTP master. But when a switch is restrated it looses its time. Can someone help me by pasting some config hints ?

Regards

t.baranski · ‎05-28-2003

Each switch is going to lose its time when it rebooted, NTP or not. But it should get the right time back via NTP when it comes back up assuming that it can reach one of its NTP peers. Are you saying that this isn't happening in your case? Perhaps posting your configurations could help someone make a diagnosis.

MUHAMMAD SHAHEEN · ‎05-29-2003

Hi,

Thanks for your reply. Here is the relevant configs pasted....

SW1 with IP 10.10.5.202 has config as follows

!

clock timezone GMT 1

clock summer-time BST recurring 4 Sun Mar 2:00 4 Sun Oct 2:00

ip subnet-zero

no ip domain-lookup

!

ntp broadcastdelay 2

ntp clock-period 17180321

ntp max-associations 10

ntp server 10.10.10.202

ntp server 10.10.10.203

The above gets rebooted and does not re-sync the time with SW2. The SW2 has IP 10.10.5.203 has a config as follows:Please note there is no VLAN on these switches and its a flat networks dedicated for CCTV.

!

clock timezone GMT 1

clock summer-time BST recurring last Sun Mar 2:00 last Sun Oct 2:00

ip subnet-zero

no ip domain-lookup

!

!!

ntp broadcastdelay 2

ntp clock-period 17180321

ntp max-associations 10

ntp server 10.10.5.203

ntp server 10.10.5.202

end

the remaining 2 switches have exactly same config except the IP which is 10.10.5.204 and 10.10.5.205.

Any help will be much appriciated. I have 4 switches in total they all are C2950G-24-EI. Each one is in a separate building linked via Fibre. What I want to achieve is to setup all or at least 2 of them as ntp server so if any one or 2 of them gets rebooted, they should be able to re-sync the time with another.

Thanks

t.baranski · ‎05-29-2003

Have a look at the following: http://www.cisco.com/en/US/tech/tk648/tk362/technologies_white_paper09186a0080117070.shtml

I think you want to utilize the "ntp peer" and "ntp master" commands to put your switches in so-called symmetric active/passive mode. I've never tried to do this before but the above link indicates that it is indeed possible.

MUHAMMAD SHAHEEN · ‎05-30-2003

I have tried all these commands but I am getting no where. Does this mean C2950's do not have ntp server functionality ? Can anyone through some lights on this?

Or is it me doing something wrong ????

Many Thanks

mchallandes · ‎06-02-2003

I did try these 2, no success either..

I have the feeling that the 2950 needs and external clock to be syncronised...

Any other comments welcome