Just looking for some ideas to troubleshoot a Mgt Vlan issue. We have quite a large, flat L2 network running RSTP and have been having issues with the VLAN for some time. Basically its flakey with some switches (and devices behind them) dropping packets and inaccessible on Vl10. In such cases its possible to an extended ping to the device which wakes it up and then apparently populates the ARP cache. Vlan 10 interfaces are also showing ?ignored? errors and, to a lesser extent, ?throttles?.
? Approx 15 x 2950s run at aggregation layer and terminate on a 6506
? No physical errors on the trunk interfaces. No bandwidth saturation issues.
? High number ARP Vs IP packets on the mgt VLAN. Debug ARP showed no problems.
? Large number of throttles in Vlan.
? Large number of broadcasts in Vlan (especially in relation to input traffic).
? Large number of ignored packets in Vlan. Ignored packets are normally symptomatic of buffer/CPU issues which is not the case and Cisco docs don?t offer any further troubleshooting advice.
? ?Storm-control broadcast level x.x? and ?storm-control action trap? have been enabled on the trunk ports along with the ?allowed VLAN? cmd.
? The ARP time out default has also been changed from the default to 5 minutes to no effect (may account for some of the additional ARP traffic).
? There are also some trunks running the ?native vlan 10? cmd which Im not able to remove as it prevents access to the devices behind it. Carrying untagged traffic into Vlan may be an issue but wouldn?t be responsible for ?ignored? packets?
? Mgt VLAN is also using process switching.
Anyone had any similar issue or any ideas re any further troubleshooting? An example output from one of the 2950s below.
*Ignored and b?cast packets*
2950_01#sh int vlan 10
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
By default, all layer 2 ports are in dynamic desirable mode, so the layer 2 port tries to form a trunk link and sends out DTP packets to the remote device. When a layer 3 interface is connected to a layer 2 switchport, it is not able to interpret these frames, which results in Input errors, WrongEncap errors, and Input queue drops.
In order to resolve this, change the mode of the switch port to static access or trunk as per your requirement.
Maybe you can clarify or maybe I dont understand , you say it is a management vlan 10 . Is this really a management vlan in which it is just used to manage the the 2950's and you have a different vlan trunked along with it for the data ? If so then yes there seems to be too much data flowing across that vlan to be strictly a mgt vlan, half a meg per second for a mgt. vlan is too much . You might start looking for somewhere someone has accidently bridged your mgt and data vlan together . Also use the bug toolkit to look for bugs related to the code versions you are using.
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.