Its a small doubt, please clarify- When STP Max age timer expires, we can conclude that Root Bridge is down . what conclusion we can made when STP Hello timer expires on a non root bridge? If a non root bridge doesnt get a Configuraton BPDU with in a Hello interval , i.e for 10 seconds, then will the non-root bridge will wait till max age timer expires or will non-root bridge take action before max age timer expires?
The Hello timer dictates the frequency of sending Configuration BPDUs and is set to 2 sec by default. If the Hello timer expires, a new BPDU is originated and sent out. Note that if a switch is not authorized to originate a BPDU then it does not use the Hello timer at all. In Legacy 802.1D STP, only root bridge originated BPDUs and they were only relayed by other switches. However, other switches did not originate their own Configuration BPDUs. If the STP driver failed on the root bridge, there would be 20 seconds (max_age) of no BPDUs in the network at all.
The RSTP changes this a bit: each switch in RSTP originates its own BPDUs on Designated ports. So when the Hello timer expires on any switch, it sends out a Configuration BPDU.
So in 802.1D if a non root bridge doesnt receive configuration BPDUs in
Hello time interval, will the non-root bridge take any actions or will
it wait untill max age timer expires?
It will wait until max_age timer expires. Remember, because a non-root bridge does not generate its own BPDUs, the Hello timer is of no use for such a switch. The Hello timer is used exclusively to control the sending of BPDUs.
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.