From 40744ef53956f8c82ada68ad2a17385e98788ced Mon Sep 17 00:00:00 2001 From: Kieran Forde Date: Mon, 14 Jul 2014 17:13:17 +0100 Subject: [PATCH] Gives clearer definition of a Linux Bridge Linux bridge doesn't behave like a hub, it behaves like a switch. Change-Id: I07a9d528f7a250ad00e7d728fb67c08230a5bf3c Closes-Bug: 1342619 --- .../networking/section_networking-scenarios.xml | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/doc/admin-guide-cloud/networking/section_networking-scenarios.xml b/doc/admin-guide-cloud/networking/section_networking-scenarios.xml index 685ce17ee3..3d1eca2495 100644 --- a/doc/admin-guide-cloud/networking/section_networking-scenarios.xml +++ b/doc/admin-guide-cloud/networking/section_networking-scenarios.xml @@ -103,10 +103,17 @@ bridge_mappings = physnet2:br-eth1 virtual network interfaces. An ethernet frame sent to one end of a veth pair is received by the other end of a veth pair. Networking uses veth pairs as virtual patch cables to make connections between virtual bridges. - A Linux bridge behaves like a hub: you can - connect multiple (physical or virtual) network interfaces devices to a Linux bridge. - Any ethernet frames that come in from one interface attached to the bridge is - transmitted to all of the other devices. + A Linux bridge behaves like a simple MAC + learning switch: you can connect multiple (physical or virtual) network + interfaces devices to a Linux bridge. The Linux bridge uses a MAC caching table to record + which interface on the bridge is used to communicate with a host on the link. + For any ethernet frames that come in from one interface attached to the bridge, the + host MAC address and port on which the frame was received is recorded in the MAC caching + table for a limited time. When the bridge needs to forward a frame, it will check + to see if the frame's destination MAC address is recorded in the table. If so, + the Linux bridge forwards the frame through only that port. If not, the frame + is flooded to all network ports in the bridge, with the exception of the port + where the frame was received. An Open vSwitch bridge behaves like a virtual switch: network interface devices connect to Open vSwitch bridge's ports, and the ports can be configured much like a physical switch's ports, including VLAN