#cisco-catalyst

Fix: Native VLAN mismatch and missing VLAN? #dev #programming #solution

Native VLAN mismatch and missing VLAN?

I’m trying to wrap my head around what exactly is going on here with a new site’s configuration of their networking stack. This particular piece I am working is pretty simple but I having a hard time figuring out what the original intention was. There is a Cisco Catalyst 3750x with three Port Channels (each with four interfaces a piece) going to three ESXi…

Fix: HP to Cisco spanning tree root flapping #programming #development #solution

HP to Cisco spanning tree root flapping

Per a recent question I recently configured both my HP (2x 2900) and Cisco (1x 3750) hardware to use MSTP for interoperability. I thought this was functional until I applied the change to the third device (HP switch 1 below) at which time the spanning tree root started flapping causing performance issues (5% packet loss) between my two HP switches. I’m not…

Fixed: High latency/drops between Cisco switches in two locations. How to troubleshoot? #answer #it #programming

High latency/drops between Cisco switches in two locations. How to troubleshoot?

I’m receiving user complaints about poor network application performance between two parts of a large warehouse facility. The software is a curses-based terminal application running on a Linux server. The clients are PCs running a telnet or SSH client. The trouble started a day ago with no recent (known) changes to…

Fixed: Is my Cisco switch port bad? #computers #solution #fix

Is my Cisco switch port bad?

I’ve been chasing a packet-loss and network stability issue for a handful of end-users on an internal network for the past few days… These issues surfaced last week, however the location was struck by lightning six weeks ago.

I was seeing 5-10% packet loss between a stack of four Cisco 2960’s and several PC’s and phones on the other side of a 77-meter run. The PC’s…