Cluster building is becoming ever-more common with InfiniBand, but these clusters
never operate in isolation. This means a connection to the outside world, one
that runs Ethernet. With the ConnectX hardware architecture from Mellanox, the
two networking fabrics come together ().
The ConnectX hardware interface will find a home in Mellanox's next iteration
of host adapter chips. The same interface will be used for both InfiniBand and
the new Ethernet chips. Planned as an interface with Ethernet and InfiniBand
interfaces, the first chip will target the cluster nodes between an Ethernet
front end and InfiniBand back end ().
This approach works well because 10-Gbit (10G) Ethernet uses the same serial-deserializer
(SERDES) as InifiniBand. Mellanox implements stateless Ethernet hardware acceleration
that brings significant performance advances with low host overhead, but it's
less than a TCP/IP offload engine (TOE). Most TOE implementations running at
1 Gbit/s already consume more than twice the power than InfiniBand, which runs
significantly faster (40 Gbits/s/port).
The InfiniHost III Ex Dual-Port InfiniBand adapter consumes only 6 W. The stateless
approach will use more host resources, but it will already have extra cycles
available because the Infini-Band interface imposes significantly less host
overhead.
COMPATIBILITY IS KEY
ConnectX is compatible with standard IP-based protocols used with Ethernet,
including IP, TCP, UDP, ICMP, FTP, ARP, and SNMP, making it compatible with
third-party 1-Gbit/s and 10-Gbit/s Ethernet products. These protocols work over
InfiniBand as well, though it's more efficient to use the OpenFabric interface.
The InfiniBand interface will include all of the InfiniHost III features, including
OpenFabric RDMA (remote direct memory access) support. The Ethernet interface
doesn't provide the RDMA support.
Some vendors of TOE Ethernet adapters have promised or are delivering RDMA
support (see "iSCSI Does 10G Ethernet" at www.electronicdesign. com, ED Online
ID 13285). InfiniBand offers other features, such as quality-of-service support
and end-node application congestion management.
PRICE AND AVAILABILITY
Single-and dual-port InfiniBand-only adapters are
available from Mellanox right now. The mixed Ethernet/InfiniBand adapters will
arrive in the first quarter of 2007. Both 1-Gbit/s and 10-Gbit/s Ethernet interfaces
will be available. Pricing is expected to be comparable to the InfiniBand adapters.
Mellanox
www.mellanox.com