From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- Documentation/networking/vxlan.rst | 88 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 Documentation/networking/vxlan.rst (limited to 'Documentation/networking/vxlan.rst') diff --git a/Documentation/networking/vxlan.rst b/Documentation/networking/vxlan.rst new file mode 100644 index 000000000..2759dc1cc --- /dev/null +++ b/Documentation/networking/vxlan.rst @@ -0,0 +1,88 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================================== +Virtual eXtensible Local Area Networking documentation +====================================================== + +The VXLAN protocol is a tunnelling protocol designed to solve the +problem of limited VLAN IDs (4096) in IEEE 802.1q. With VXLAN the +size of the identifier is expanded to 24 bits (16777216). + +VXLAN is described by IETF RFC 7348, and has been implemented by a +number of vendors. The protocol runs over UDP using a single +destination port. This document describes the Linux kernel tunnel +device, there is also a separate implementation of VXLAN for +Openvswitch. + +Unlike most tunnels, a VXLAN is a 1 to N network, not just point to +point. A VXLAN device can learn the IP address of the other endpoint +either dynamically in a manner similar to a learning bridge, or make +use of statically-configured forwarding entries. + +The management of vxlan is done in a manner similar to its two closest +neighbors GRE and VLAN. Configuring VXLAN requires the version of +iproute2 that matches the kernel release where VXLAN was first merged +upstream. + +1. Create vxlan device:: + + # ip link add vxlan0 type vxlan id 42 group 239.1.1.1 dev eth1 dstport 4789 + +This creates a new device named vxlan0. The device uses the multicast +group 239.1.1.1 over eth1 to handle traffic for which there is no +entry in the forwarding table. The destination port number is set to +the IANA-assigned value of 4789. The Linux implementation of VXLAN +pre-dates the IANA's selection of a standard destination port number +and uses the Linux-selected value by default to maintain backwards +compatibility. + +2. Delete vxlan device:: + + # ip link delete vxlan0 + +3. Show vxlan info:: + + # ip -d link show vxlan0 + +It is possible to create, destroy and display the vxlan +forwarding table using the new bridge command. + +1. Create forwarding table entry:: + + # bridge fdb add to 00:17:42:8a:b4:05 dst 192.19.0.2 dev vxlan0 + +2. Delete forwarding table entry:: + + # bridge fdb delete 00:17:42:8a:b4:05 dev vxlan0 + +3. Show forwarding table:: + + # bridge fdb show dev vxlan0 + +The following NIC features may indicate support for UDP tunnel-related +offloads (most commonly VXLAN features, but support for a particular +encapsulation protocol is NIC specific): + + - `tx-udp_tnl-segmentation` + - `tx-udp_tnl-csum-segmentation` + ability to perform TCP segmentation offload of UDP encapsulated frames + + - `rx-udp_tunnel-port-offload` + receive side parsing of UDP encapsulated frames which allows NICs to + perform protocol-aware offloads, like checksum validation offload of + inner frames (only needed by NICs without protocol-agnostic offloads) + +For devices supporting `rx-udp_tunnel-port-offload` the list of currently +offloaded ports can be interrogated with `ethtool`:: + + $ ethtool --show-tunnels eth0 + Tunnel information for eth0: + UDP port table 0: + Size: 4 + Types: vxlan + No entries + UDP port table 1: + Size: 4 + Types: geneve, vxlan-gpe + Entries (1): + port 1230, vxlan-gpe -- cgit v1.2.3