Switch entering into sleep mode

vinoth.kumar · ‎11-26-2008

Hi,

We are using the catalyst 6500 with the CATOS (WS-C6506 Software, Version NmpSW: 8.1(3)) In that we have created one management interface SC0 and 4 VLAN interface in switch

Now our problem is Still its a new site there is no traffic between the interface so what suddenly when we start to ping some interface IP it REQUST TIMED OUT for the few times and getting the reply

i suggesting it might be interface is going in sleep mode

Please advice me

Regards,

Vinu

John Blakley · ‎11-26-2008

The arp entry is timing out. When it can't find an entry in the table, it will broadcast for the owner of the address. When the mac address is found, it will add the arp entry to it's table and start responding to pings. You can check this by doing:

sh arp | inc

on the switch. If it comes back to the prompt without any results, then it's not in the table. You can then ping the device, and do the same command above, and it should be there.

HTH,

John

HTH, John *** Please rate all useful posts ***

sachinraja · ‎11-26-2008

Hello Vinodh

There is nothing called a "sleep mode" on cisco devices.. If it sleeps, the admins would be DEAD !

One reason to this might be because of the ARP entries aging out ! if you do not have IP communication happening, the ARP table can drop out the entry, and when you try pinging again, after a while, it might take 2-3 seconds to build up the entry ! that is why you can see a coupple of drops before the connection gets established..

this is true only for PC ports, but not point to point interfaces ! Request timed can happen due to other reasons too.. Bad link (look at reliability), duplex/ speed mismatches on switches etc.. So you gotta analyze everything

Hope this helps.. all the best..

Raj