Kategorie: Linux Networking

All around Linux networking

Switching Performance – Chaining OVS bridges

The Openvswitch installed on a Linux system provides the feature to configure multiple bridges. Multiple OVS bridges behave like independent local switches. This is the way OVS is providing switch virtualization. It is possible to chain multiple OVS bridges on one system. Chaining multiple bridges is used by Openstack neutron, when using the default networking […]

Updated: 17/01/2021 — 13:18

Openstack Neutron using VXLAN

The networking part of Openstack provides several models for the L2 networks to be used as L2 tenant broadcast domains. An overlay network can be used to separate the MAC addresses and „vlans“ of the tenant networks from the transport layer network. Openstack neutron in Havana supports two overlay network technologies, GRE and VXLAN. VXLAN […]

Updated: 17/01/2021 — 13:18

How to find namespaces in a Linux system

Namespaces in Linux are heavily used by many applications, e.g. LXC, Docker and Openstack. Question: How to find all existing namespaces in a Linux system? The answer is quite difficult, because it’s easy to hide a namespace or more exactly make it difficult to find them. Exploring the system In the basic/default setup Ubuntu 12.04 […]

Updated: 17/01/2021 — 13:18

Linux Network Namespaces – Background

Namespaces Managing network namespaces using the ip command is the prefered way. It is helpful to understand, what’s going on in the (kernel) background. If you create two network namespaces using ip netns add ns1 ip netns add ns2 you find to entries in the directory /var/run/netns/ ls -la /var/run/netns/ total 0 drwxr-xr-x 2 root […]

Updated: 17/01/2021 — 13:18

Switching Performance – Connecting Linux Network Namespaces

In a previous article I have shown several solutions to interconnect Linux network namespaces (http://www.opencloudblog.com). Four different solutions can be used – but which is the best solution with respect to performance and resource usage? This is quite interesting when you are running Openstack Networking Neutron together with the Openvswitch. The systems used to run these […]

Updated: 26/04/2014 — 15:25

Linux Switching – Interconnecting Namespaces

Switching in software on Linux is one of the important parts when using virtualization technologies like KVM or LXC. Typical hosts do not provide one or more physical adapters for each NIC of a virtual machine in KVM or per container when using LXC. Something else must take the part to interconnect the virtual network […]

Updated: 18/05/2014 — 10:56