OSS_SNMP is a PHP SNMP library written by myself for people who hate SNMP. After a customer migration from PVST to MST (Multiple Spanning Tree), I have added a number of MST functions / MIBs to OSS_SNMP:
During a fairly significant network migration involving breaking / connecting a number of links, I wanted to be able to monitor the MST port role of significant ports at a glance. For this purpose, I wrote the mst-port-roles.php script and have committed it as an example to OSS_SNMP. First, here is what it looks like when run on the command line (with hostnames obfuscated):
From a very simple array of port details at the top of the script, it will poll all switches and for each port print:
- device and port name;
- port state and speed;
- port role for each applicable MST instance.
I run it on bash and use bash colouring. The script is well documented and can easily be repurposed for other networks. You’ll find the source here.
NOCtools (a mixed bag collection of tools and utilities for NOC engineers) and OSS_SNMP (a PHP SNMP Library for People Who HATE SNMP, MIBs and OIDs) have just gotten support for Multiple Spanning Tree.
Specifically, OSS_SNMP has two new MIBS (Cisco’s original MST tree which has a lot of deprecated nodes – MIBS\Cisco\MST; and the newer IEEE tree – MIBS\Cisco\SMST). With these, we can, for example, get an array of
[instanceID] => instanceName values from a switch by just coding:
$ciscosw = new \OSS_SNMP\SNMP( $ip, $community );
print_r( $ciscosw->useCisco_SMST()->instances() );
NOCtools has the more impressive use cases of these new features. Specifically (and just likes its RSTP/pvrspt functionality), it can:
- Show MST port roles (root, designated, alternate, etc) for a given (or all) MST instance(s) – this is equivalent to the RSTP version;
- From a given device, it can crawl all CDP neighbours and create a graph of all devices, their connecting ports and the MST roles of those ports. This is a really useful feature as it means you don’t need to log into multiple switches to get a handle on what links are blocking. See documentation and a sample diagram here.