lldp

LLDP is a wonderful protocol which paints a picture of datacenter topology. lldpd is a daemon to run on your servers to receive LLDP frames outputs network location and more. There’s also a recently patched lldp Ansible module. Like all tools, using LLDP/lldpd has had some issues. Here’s the ones I’ve seen in practice, with diagnosis and resolution: Switch isn’t configured to send LLDP frames Diagnosing: [code] tcpdump -i eth0 -s 1500 -XX -c 1 ’ether proto 0x88cc' [/code]...

Similar to this thread, I wanted to see what VLANs were allowed for a trunked port as reported by SNMP with Python. With the help of a couple of colleagues, I made some progress. [code language=“python”] vlan_value = ‘000000000020000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000’ for key,value in enumerate(format(int(vlan_value, 16), “0100b”).rjust(len(vlan_value) * 4, ‘0’)): … if value == ‘1’: … print key … … … 42 146 [/code] Convert the string returned to Hex Convert that to Binary Right fill 0s to the appropriate length to give offset (determined by the size of the string) Loop through the resulting value and each character that is a 1 is an enabled VLAN on the port In conjunction with LLDP, I’m able to query each switch/port and interface is connected to and determine if the VLANs are set properly on the port....