NAME¶
vale
—
a very fast Virtual Local Ethernet using the netmap
API
SYNOPSIS¶
device netmap
DESCRIPTION¶
vale
is a feature of the
netmap(4) module that implements multiple Virtual
switches that can be used to interconnect netmap clients, including traffic
sources and sinks, packet forwarders, userspace firewalls, and so on.
vale
is implemented completely in software,
and is extremely fast. On a modern machine it can move almost 20 Million
packets per second (Mpps) per core with small frames, and about 70 Gbit/s with
1500 byte frames.
OPERATION¶
vale
dynamically creates switches and ports
as clients connect to it using the
netmap(4) API.
vale
ports are named
vale[bdg:][port] where
vale is the prefix indicating a VALE switch
rather than a standard interface,
bdg
indicates a specific switch (the colon is a separator), and
port indicates a port within the switch.
Bridge and port names are arbitrary strings, the only constraint being that
the full name must fit within 16 characters.
See
netmap(4) for details on the API.
LIMITS¶
vale
currently supports up to 4 switches, 16
ports per switch, with 1024 buffers per port. These hard limits will be
changed to sysctl variables in future releases.
SYSCTL VARIABLES¶
vale
uses the following sysctl variables to
control operation:
- dev.netmap.bridge
- The maximum number of packets processed internally in each iteration.
Defaults to 1024, use lower values to trade latency with throughput.
- dev.netmap.verbose
- Set to non-zero values to enable in-kernel diagnostics.
EXAMPLES¶
Create one switch, with a traffic generator connected to one port, and a
netmap-enabled tcpdump instance on another port:
tcpdump -ni vale-a:1 &
pkt-gen -i vale-a:0 -f tx &
Create two switches, each connected to two qemu machines on different ports.
qemu -net nic -net netmap,ifname=vale-1:a ... &
qemu -net nic -net netmap,ifname=vale-1:b ... &
qemu -net nic -net netmap,ifname=vale-2:c ... &
qemu -net nic -net netmap,ifname=vale-2:d ... &
SEE ALSO¶
netmap(4)
http://info.iet.unipi.it/~luigi/vale/
Luigi Rizzo, Giuseppe Lettieri: VALE, a switched ethernet for virtual machines,
June 2012,
http://info.iet.unipi.it/~luigi/vale/
AUTHORS¶
The
vale
switch was designed and implemented
in 2012 by
Luigi Rizzo and
Giuseppe Lettieri at the Universita` di
Pisa.
vale
was funded by the European Commission
within FP7 Projects CHANGE (257422) and OPENLAB (287581).