Arista switch pioneers 100 GbE uplinks in top-of-rack

Arista Networks announced the industry's first top-of-rack switch to offer 100 GbE uplink ports. It also introduced a universal transceiver that will allow data center operators to upgrade network links from 10 to 40 GbE without replacing cables.

The 7280E is a new top-of-rack Arista switch series designed for high-end data centers. It has 100 Gigabit Ethernet (GbE) uplink ports, 9 GB of packet buffering capacity, and a hitless software upgrade feature.

There are three models in the 7280E Arista switch series, each shipping with 48 server-facing 1/10 GbE ports. The models vary in their uplink port configurations.

• The Arista 7280SE-72 has two MXP interfaces, which enable uplink port combinations of dual 100 GbE, 6x40 GbE or 24x10 GbE.
• The Arista 7280SE-68 has two QSFP 100 interfaces, which enable uplink port combinations of dual 100 GbE, 2x40 GbE or 8x10 GbE.
• The Arista 7280SE-64 has four QSFP+ interfaces, which can support either 4x40 GbE or 16x10 GbE uplinks. This model is for data centers that don't require 100 GbE uplinks, but need the other features of the 7280E.

The 100 GbE uplinks on the 7280E series will help data centers that are seeing saturation of their 40 GbE uplinks. "If you have high-performance computing or storage nodes on [hosts], you'll see most of them have the ability to push 10 Gb on a per-flow basis," said Martin Hull, Arista's senior product line manager. "You can fill a pipe with just four flows. Replacing those uplinks with 100 Gb will bring better throughput and performance."

Only Arista's most advanced customers will need 100 GbE uplinks today, said Christian Renaud, senior analyst at 451 Research, especially those who take advantage of servers with 10 GbE network interface cards (NICs) and use technologies like Intel's Data Plane Development Kit to offload packet processing from the x86 CPU to the NIC. Renaud said those data centers are tuning their applications to be so efficient that they can push out 10 Gbps flows that demand fat uplinks to the spine or core switch.

Arista also added its Smart System Upgrade (SSU) feature to the 7280E series. SSU is a hitless software upgrade feature that allows network administrators to update the operating system on the switches with minimal network downtime. SSU was already available on Arista's 7500E spine switches, but the 7280E series will be the first top-of-rack switch with such a capability.

The 7280E SSU feature will roll out in phases. Today, administrators can upgrade 7280E software with only 30 seconds of downtime. By the fourth quarter, SSU will reduce upgrade downtime to microseconds.

The Arista switch has unprecedented packet buffering capacity. Most top-of-rack switches ship with no more than a few dozen megabytes, but the 7280E ships with 9 GB of buffer memory.

"It's all to reduce packet loss and retransmissions, because packet retransmissions exacerbate network problems," said Mike Fratto, principal analyst at Current Analysis. "It's meant for bursts. If you're not running a leaf-spine [network] with one-to-one [subscription ratios], you're going to have oversubscription. Buffering helps. [Arista] can get to 100 milliseconds of buffering at every port."

Both the 7280E series and the universal transceiver are shipping today. The 7280SE-64 sells for less than $500 per port, or about $32,000. The 7280SE-72, which ships with embedded optics, sells for about $50,000, Hull said.

Arista's universal 40 GbE optics

Arista's 40G-UNIV QSFP transceiver allows 40 GbE to run over a single pair of multi-mode or single-mode fiber that the typical data center already has in place for 10 GbE networks. Most 40 GbE network links require four pairs of such fiber.

"The universal transceiver is using four different wavelengths," said Current Analysis' Fratto. "Rather than using four strands of 10 Gb, they're using one strand of 10 Gb, but using four wavelengths to transmit the data. So you can use your existing fiber. That's a big deal."

The Arista 40G-UNIV will have a reach of 150 meters over multi-mode fiber and 500 meters over single-mode fiber. It will also interoperate with IEEE LR4 optics, Arista said.

Arista 7500E spine switch updates

Arista extended its Data Analyzer (DANZ) feature to its 7500E spine switch, which will allow engineers to use the chassis as a network packet broker. Arista also enhanced DANZ tap aggregation management, deep packet inspection and advanced traffic steering functions.

Finally, Arista added OpenFlow 1.3 support to the 7500E. This feature will immediately enable its research and university customers to establish 100 GbE connections to Internet2 for bulk data transfers, Arista's Hull said.

Let us know what you think about the story; email: Shamus McGillicuddy, news director, or follow him on Twitter @ShamusTT.