Continuing my week in Chicago, for the IBM Storage Symposium 2009, I attended what in my opinion was the bestsession of the week. This was by a guy named Chip Copper, who covered IBM's set of Ethernet and Fibre Channelnetworking gear. Attributes are the four P's:
- Performance, non-blocking
- Port density
- Power and Cooling (electricity usage)
Equipment comes in two flavors: Top-of-Rack (ToR) thin pizza box switches, and Middle-of-Row (MoR) much larger directors.The MoR directors are engineered for up to 50Gbps per half-slot, so 10GbE and the future 40GbE can be easily accommodated in a single half-slot, and the future 100GbE can be done with a full slot (two half-slots).
While many companies might have been contemplating the switch from copper wires to optical fiber, there is a new reason for copper cables: Power-over-Ethernet (PoE). Many IP-phones, digital video surveillance cameras, and other equipment can have a single cable that delivers both signal and electricity over copper. If you have already deployed optical fiber throughout the building, there are "last mile" options where the signals are converted to copper wires and electrical energy added for these types of devices.
Two directors can be connected together with Inter-Chassis Link (ICL) cables to make them look like a single director with twice the number of ports. These are different than Inter-Switch Links (ISL) as they are not counted as an extra "hop" for networking counting purposes, especially important for FICON usage.
Today, we have 1Gbps, 2Gbps, 4Gbps and 8Gbps Fibre Channel. Since these all use 10-for-8 encoding (10 bits represents one 8-bit byte), then in was easy to calculate throughput: 8Gpbs was 800 MB/sec, for example. Auto-negotiation between speeds is not done at the HBA card, switch or director blade itself, but in the Short Form-factor Pluggable (SFP) optical connector. However, you can only auto-negotiate if the encoding matches. The 4/2/1 SFP can run at 4Gbps or auto-negotiate to slower 2Gbps and 1Gbps. The 8/4/2 SFP can run at 8Gbps, or auto-negotiate down to slower 4Gpbs and 2Gbps. Folks who still have legacy 1Gbps equipment, but want to run some things at 8 Gbps, can buy 8Gbps-capable switches or director blades, but then put some 4/2/1 SFPs into them. These 4/2/1 SFP are cheaper, so this might be something to consider if budgets are tight. Some SFPs handle up to 10km distances, but others only 4km, so be careful not to order the wrong ones.
Unfortunately, there are proposals in place for 10Gbps and 40Gbps that would use a different 66-for-64 encoding (66 bits represent 8 bytes), so 10Gbps would be 1200 MB/sec. These are used today for ISL between directors and switches.In theory, the 40Gbps could auto-negotiate down to 10Gbps, but not to any of the 8/4/2/1 Gbps that use different 10-for-8 encoding.
For those who cannot afford a SAN768B, there is a smaller SAN384B that can carry: 192 ports (4Gpbs/2Gbps), 128 ports (8Gbps) or 24 ports (10Gbps). The SAN384B can be ICL connected to another SAN384B or even the SAN768B as your needs grow.
On the entry-level side, the SAN24B-4 offers a feature called "Access Gateway". This makes the SAN24B look like an SAN end-point host, rather than a switch, and makes initial deployment of integrated bundled solutions easier. Once connected to everything, you can convert it over to full "switch" mode.The SAN40B-4 and SAN80B-4 provide midrange level support, including Fibre Channel routing at the 8Gbps level. In fact, all 8Gbps ports include routing capability. IBM offers both single-port and dual-port 8Gbps host bus adapter (HBA) cards to connect to these switches. These HBA offer 16 virtual channels per port, so that if you have VMware running many guests, or want to connect both disk and tape to the same HBA, you can keep the channel traffic separate for Quality of Service (QoS).
Chip wrapped up his session to discuss Fibre Channel over Ethernet (FCoE), and explained why we need to have a loss-less Convergence Enhanced Ethernet (CEE) to meet the needs of storage traffic as well as traditional Fibre Channel does today. IBM offers all of the equipment you need to get started today on this FCoCEE, with Converged Network Ethernet cards for your System x servers, and a new SANB32 that has 24 10GbE CEE ports and 8 traditional 8Gbps FC ports. This means that you can put the CNA card in your existing servers, connect to this switch, and then connect to your existing 10GbE LAN and your existing 8Gpbs or 4Gpbs FC-based SAN to the rest of your storage devices.
Worried that the FCoE or CEE standards could change after you deploy this gear? Aren't most LAN and SAN switches based on Application-specific integrated circuit [ASIC] chips which are created in the factory? Don't worry, IBM's equipment have put all the standards-vulnerable portions of the logic into separate Field-programmable gate array [FPGA] that can be updated with simplya firmware upgrade. This is future-proofing I can agree with!