Information Technology Reference
In-Depth Information
The Logical Domains manager implements duplicate MAC address detection
by sending multicast messages with the address it wants to assign and listening
for a possible response from another machine's Logical Domains manager saying
the address is in use. If such a message comes back, it randomly picks another
address and tries again. The message time-to-live (TTL) is set to 1, and can be
changed by the SMF property
ldmd/hops
. Recently freed MAC addresses from
removed domains are used first, to help prevent DHCP servers from exhausting
the number of addresses available.
3.3.2.2 Network Connectivity
Virtual switches are usually assigned to a physical network device, permitting
traffic between guest domains and the network segment to which the device is
connected. Network traffic between domains on the same virtual switch does not
travel to the virtual switch or to the physical network, but rather is implemented
by a fast memory-to-memory transfer between source and destination domains
using dedicated LDCs. Virtual switches can also be established without a con-
nection to a physical network device, which creates a private secure network not
accessible from any other server. Virtual switches can be configured for securely
isolated VLANs, and can exploit features such as VLAN tagging and jumbo frames.
3.3.2.3 Hybrid I/O
Network Interface Unit (NIU) Hybrid I/O is an optimization feature available on
servers based on the UltraSPARC T2 chip, the T5120 and T5220 servers, and the
Sun Blade T6320 server module. It is an exception to the normal Logical Domains
virtual I/O model, and provides higher performance network I/O. In hybrid mode,
DMA resources for network devices are loaned to a guest domain so it can perform
network I/O without going through an I/O domain. In this mode, a network device
in a guest domain can transmit unicast traffic to and from external networks
at essentially native performance. Multicast traffic, and network traffic to other
domains on the same virtual switch are handled as described above.
In current implementations, there are two 10 GbE NIU
nxge
N
devices per T2-
based server. Each can support three hybrid I/O virtual network devices, for a
total of six.
Service domains can have virtual disk services that export virtual block devices to
guest domains. Virtual disks are based on back-end disk resources, which may be
physical disks, disk slices, volumes, or files residing in ZFS or UFS file systems.
These resources could include any of the following:
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