We had core(4503), distribution(3750), and access switches(2960) in our environment. Currently we configured the clock manually in each switch, but a reboot of the switch resets the clock also. We are planning to make a single switch as a NTP servers and others are clients to synchronise the correct time even after a reboot of the access switches.
Kindly provide valuable suggessions and advise regarding the requirement.
We have configured successfully the NTP in our environment as core switch as ntp master (currently not using the public NTP server, manually configured clock in the core switch) because the core switch having redundant power supply (least chance of a downtime to the switch). But as a worst case scenario if the entire power outage occurs, a chance of wrong time replication will happen.
1) Is there any way we can configure a hardware clock in the core switch(retain the date and time even after the reboot)?
If a switch is configured with ntp server to get NTP time from an external server (which I believe is what you are suggesting) then there is no need to configure ntp master. Once the switch has learned authoritative time from the external server then the switch will automatically be able to act as ntp server to other switches in the network.
If you do configure a switch with the command ntp master then the switch will assert that it has authoritative time and will offer NTP time to other devices even if it has not learned time from the external server. There is a scenario which illustrates what could happen:
- assume that you have configured the core 4503 as ntp master.
- if there is also configured ntp server, then assume that something has happened to disrupt connectivity from the 4503 to the external server.
- something causes the 4503 to reboot.
- when it comes up the 4503 will be using the arbitrary Cisco start time and date.
- since the switch is ntp master it will start announcing its time to clients in the network.
- now all the network devices are using that arbitrary Cisco date.
So I suggest that you be very careful about configuring ntp master on any device that does not have a reliable source for time.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.