Category: Switching
Catalyst 3750X licensing
While making a kit list for a network design with Cisco Catalyst 3750X switches, I got confused while looking at the different licensing features. The Cisco Catalyst 3750X switches are available with multiple licensing options, which can be upgraded. A new switch can be ordered with two licensing options. These are LAN Base (Enhanced Intelligent … Read More
Cisco error message: %SYS-2-MALLOCFAIL
While looking through some logging on a switch (Cisco Catalyst 3550), I noticed the following messages popping up multiple times in the buffer logging. -Process= "Pool Manager", ipl= 0, pid= 5 -Traceback= 1A57D0 1A6DF4 161B3C 1B2BF0 1B2E38 1C6440 Jan 26 14:45:48.970 CET: %SYS-2-MALLOCFAIL: Memory allocation of 1680 bytes failed from 0x161B38, alignment 0 Pool: I/O … Read More
Configuration Example, Switching
Link State Tracking
Last week a friend called me and told me he was having serious problems with his network. A complete blade environment wasn’t able to communicate with the rest of the network. I asked what changed in the network and he told me that he had added a VLAN to a trunk allowed lists. Because he … Read More
NVRAM corrupt or broken?
Today some of my colleagues and I “rebuild” an existing ESX with NetApp network. We change multiple VLAN’s and did a lot of reconfiguring. Unfortunately some other people were working on the power, so sometimes all equipment had to power down. After we did our job, we started testing the environment. All DMZ VM’s weren’t … Read More
Cisco ASA & ESX: strange ARP behavior
Last week I had a very strange problem with a Cisco ASA firewall. The firewall is configured with multiple interfaces, including a DMZ interface. There are multiple servers in the DMZ. These servers are physical and virtual servers. The virtual servers are VMware servers in a blade environment. I configured the feature ip verify reverse-path … Read More
IEEE 802.3x FlowControl between Cat3750E and Cat2960
I have a network with two Catalyst 3750E switch stacks, which are connected with a 2 x 10Gbps Etherchannel. Every stack facilitates a ring topology of approximately 10 to 15 Catalyst 2960 switches. Two of the 2960 are connected with 1Gbps links to a switch stack to create the ring topology. So lets say that … Read More