NAME

libvdeplug_multi - multiplexing vdeplug module: multilink

SYNOPSIS

libvdeplug_multi.so

DESCRIPTION

This is a libvdeplug multiplex module implementing a multilink.

The common usage of this module is to support (usually temporary) multiple links between virtual machines or switches. This module can be used to implement hand-offs betweek links: a new link can be set-up and then the old one is closed. When both links are active, packets can be duplicated.

This module of libvdeplug4 can be used in any program supporting vde like vde_plug, kvm, qemu, user-mode-linux and virtualbox.

The vde_plug_url syntax of this module is the following:

multi://[path]
multi://[path][[OPTION][/OPTION][/OPTION]...]

If path is omitted the path of the multi is /tmp/vdenode_$USERNAME (e.g. /tmp/vdenode_john if the username is john).

OPTIONS

mode=MODE: define the permissions for the multilink (see chmod). MODE is an octal number. The standard permission mask is: 0600 (only processes owning to the same user can join the network).
dirmode=DIRMODE: define the permissions for the multilink control directory(see chmod). MODE is an octal number. If omitted, is computed from mode.
grp=GROUP: define the group ownership of the multilink.

EXAMPLES

multi:///tmp/multi
Other virtual machines, namespaces or vde_plug can join this multilink using vde:///tmp/hub or simply /tmp/hub
Given two virtual machines using multi:///tmp/vm1 and multi:///tmp/vm2 respectively, it is possible to connect them using vde_plug /tmp/vm1 /tmp/vm2. If the second virtual machine is running on a remote hosts; ip1.vm2.domain.org and ip2.vm2.domain.org are two ip addresses permitting to reach that remote host using different paths, the command vde_plug /tmp/vm1 = ssh ip1.vm2.domain.org vde_plug /tmp/vm2 connects the two vms. In a second time is possible to run vde_plug /tmp/vm1 = ssh ip2.vm2.domain.org vde_plug /tmp/vm2 to create another channel on the other path. When both connections are in place packets can arrive duplicated (the upper protocols can manage the problem). Then the process connecting the remotevm using ip1.vm2.domain.org can be killed, completing in this way the (hiccup-less) handoff.
multi:///tmp/multi[mode=0666]
It is the same multilink, but everybody is allowed to connect their processes.

NOTICE

Virtual Distributed Ethernet is not related in any way with www.vde.com ("Verband der Elektrotechnik, Elektronik und Informationstechnik" i.e. the German "Association for Electrical, Electronic & Information Technologies").