1 .\" Copyright (c) 2012 Luigi Rizzo, Universita` di Pisa
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36 .Nd a very fast Virtual Local Ethernet using the netmap API
43 module that implements multiple Virtual switches that can
44 be used to interconnect netmap clients, including traffic
45 sources and sinks, packet forwarders, userspace firewalls,
49 is implemented completely in software, and is extremely fast.
50 On a modern machine it can move almost 20 Million packets per
51 second (Mpps) per core with small frames, and about 70 Gbit/s
52 with 1500 byte frames.
55 dynamically creates switches and ports as clients connect
65 is the prefix indicating a VALE switch rather than a standard interface,
67 indicates a specific switch (the colon is a separator),
70 indicates a port within the switch.
71 Both SSS and PPP have the form [0-9a-zA-Z_]+ , the string cannot
72 exceed IFNAMSIZ characters, and PPP cannot be the name of any
73 existing OS network interface.
77 for details on the API.
80 currently supports up to 4 switches, 16 ports per switch, with
81 1024 buffers per port.
82 These hard limits will be
83 changed to sysctl variables in future releases.
86 uses the following sysctl variables to control operation:
87 .Bl -tag -width dev.netmap.verbose
88 .It dev.netmap.bridge_batch
89 The maximum number of packets processed internally
91 Defaults to 1024, use lower values to trade latency
93 .It dev.netmap.verbose
94 Set to non-zero values to enable in-kernel diagnostics.
97 Create one switch, with a traffic generator connected to one
98 port, and a netmap-enabled tcpdump instance on another port:
99 .Bd -literal -offset indent
100 tcpdump -ni valea:1 &
101 pkt-gen -i valea:0 -f tx &
105 each connected to two qemu machines on different ports.
106 .Bd -literal -offset indent
107 qemu -net nic -net netmap,ifname=vale1:a ... &
108 qemu -net nic -net netmap,ifname=vale1:b ... &
109 qemu -net nic -net netmap,ifname=vale2:c ... &
110 qemu -net nic -net netmap,ifname=vale2:d ... &
115 Luigi Rizzo, Giuseppe Lettieri: VALE, a switched ethernet for virtual machines,
116 June 2012, http://info.iet.unipi.it/~luigi/vale/
121 switch was designed and implemented in 2012 by
124 .An Giuseppe Lettieri
125 at the Universita` di Pisa.
128 was funded by the European Commission within FP7 Projects
129 CHANGE (257422) and OPENLAB (287581).