Ahead IT

What’s the “big deal” about Cisco UCS ver 2.0 fabric?  Two words: bandwidth and flexibility.

Cisco recently expanded the UCS product line to include an additional Fabric Interconnect (model 6248), an additional Chassis IO Module (model 2208), as well as software release 2.0 with many new features. The new 2.0 components support existing chassis and server blades, and are back-compatible to inter-operate with existing first-generation UCS hardware (in original modes of use.)

Although the new models need not obsolete the original hardware, many of the recent Cisco UCS deployments by Ahead have opted to take advantage of the benefits of the new components.

The new 6248 Fabric Interconnect packs 48 Unified Ports into a 1 RU form factor. Any of the base Unified Ports may be configured to operate as 1GE/10GE Ethernet uplinks, 8-Gbps Fibre Channel uplinks, or Fabric Ports for connecting to Server Chassis IO Modules.

The new 2208 Server Chassis IO Module (also known as a Fabric Extender or FEX) doubles the bandwidth between each UCS Server Chassis and Fabric Interconnect and quadruples the bandwidth within the chassis to each server blade.

Most importantly, UCS ver 2.0 allows the Fabric to operate in a “Port Channel” mode rather than the original “Pinning” mode of UCS ver 1.0. Take a quick look at the following diagram.

Originally the traffic from a given server blade was pinned to a single Fabric cable between Server Chassis and Fabric Interconnect, as well as a single 10GE Ethernet uplink from the Fabric Interconnect. Pinning is an effective method to distribute traffic from multiple blades across multiple uplinks. Unfortunately pinning does not share all available bandwidth, and it is hypothetically possible to saturate one link while others go unused. (Although if you’ve never tried to saturate a 10 GE link, it takes a lot of server IO.)

UCS ver 2.0 introduces Port Channeling between IO Module and Fabric Interconnect. A hashing mechanism is used to distribute all server traffic across all Fabric links in a shared manner. With UCS ver 2.0, it is now possible for a server to have full access to the bandwidth of all Fabric links.

And the best is yet to come. Cisco plans to launch the new Virtual Interface Card (VIC) model 1280 next quarter. The VIC is a mezzanine card installed on each server blade, equivalent to a Converged Network Adapter in a rack-mount server. With this generation 2 VIC, a half-width server may utilize dual 40-GE network uplinks – one 40-GE uplink through IO Module 1 and the left Fabric Interconnect and a second, additional 40-GE uplink through IO Module 2 and the right Fabric Interconnect.

Keep in mind that all of this bandwidth is available to carry both Data LAN and Storage SAN traffic, as well as system management traffic. UCS Fabric bandwidth is protected with bi-directional Quality of Service, a feature that guarantees each type of traffic (LAN, SAN or Management traffic) has at least a minimum share of bandwidth available to satisfy expected services levels.

With UCS ver 2.0, Cisco continues to drive innovation and continues to advance the vision of the virtual data center.  Give Ahead a call to put the power of unified computing to work for your organization.