TweetFollow Us on Twitter

MacTech Magazine Article Archives

Volume Number: 23 (2007)
Issue Number: 01
Column Tag: Network Administration

Jumbo Frame Networks

Tap into extra Ethernet speed

By Steve Modica

Approximately one year ago, Apple introduced its first dual Ethernet G5 PowerMac. The system sported an internal Broadcom chip that provided the user with two high-speed Gigabit Ethernet ports.

Why would Apple include a second Ethernet port on their new PowerMac systems? One reason (probably the most obvious) is for Xsan support. To add a system to an Xsan storage network (or almost any clustered filesystem network), the system must be connected to the Fibre Channel based storage, its normal internet connection, and a dedicated "Meta-data" network.

On the previous generation of PowerMacs, this would require the customer to purchase an extra Gigabit Ethernet NIC (network interface card), which uses up one PCIX or PCIE slot and requires the user to open up the machine to install the device. When you consider the extra Fibre Channel card (which may have been ordered directly from Apple), you're now down to one free PCI slot to house your high-speed video capture or other application specific devices.

Given the minimal price premium for going to a dual port Gigabit Chip from a single port, adding that second connector was a no-brainer for Apple.

Xsan and clustered filesystems in general, have a lot of promise. Systems can be attached directly to the shared storage using Fibre Channel, and the Ethernet based "meta-data" network is used as the traffic cop. It assures that multiple systems aren't modifying the same filesystem structures simultaneously.

The problem with these new filesystem technologies is the entry point cost. Purchasing an Apple XRAID is quite economical given their cost per byte ratio (one of the lowest in the industry), but when you add in the cost of a Fibre Channel switch, Fibre Channel adapters for each machine, additional Ethernet ports for the meta-data network and the software licenses, the cost begins to approach $30,000 for even the smallest network. When compared to even high-end NAS storage devices, the choice is easy.

So assuming you are one of the many 5-10 system shops that simply can't justify a $30,000 entry point for storage, but you've paid for all of these great PowerMac and Mac Pro systems with second Gigabit Ethernet ports, what can you do to take advantage of them? There's nothing worse than buying something and leaving it sit idle, especially when shared network performance is one of the most common complaints at small shops.

One very common use of these extra ports is to create a dedicated storage network that uses Gigabit Ethernet's built-in "jumbo frame" technology to speed up the transfer of data, while reducing the amount of cpu overhead created when transferring that data.

A configuration like this can significantly improve network performance for file-transfers, captures and downloads, while freeing the "normal" office network for things like email, web browsing and DHCP services. This setup will also increase the amount of CPU cycles available on the server and the clients for local image processing -- a big win for everyone in the office.

What are Jumbo Frames? Seven years ago, when Gigabit Ethernet was just becoming available, processors were a lot slower than they are today. Vendors weren't crowing about how many Ghz their systems were clocked at. They were still working on hitting the 1Ghz mark! These new "high-speed" Gigabit adapters were expensive and quirky. Finding adapters (which typically ran $1500 or more) that worked with all your platforms and a switch that worked with all your adapters was no small task.

During this period, a typical Gigabit Ethernet adapter would easily eat up an entire CPU just for interrupt processing. It was rare to see a Gigabit adapter perform at "line rate" (IE 1 Gb). More typically, adapters would get between 400 and 600Mbits/sec. This is still plenty good, but it must be remembered that while maintaining these rates, your machine wasn't doing anything else.

Enter the notion of "Jumbo Frames"

Ethernet (and all of its add-on features) are defined as IEEE 802.3. This spec includes things like auto-negotiation, link aggregation, 10MbEthernet, 100Mb/Ethernet and even 10Gb/Ethernet. The spec defines the size of an Ethernet frame as 1500 bytes -- typically somewhere between 1488 and 1514 bytes depending on the platform.

Receiving 1 billion bits of data adds up to 83,333 packets per second. Theoretically, each one of these packets requires the CPU to stop what its doing, receive the packet from the Gigabit card, process the headers, and provide the data to the waiting application (you).

At 83,333 packets per second, most of the CPUs time is spent context switching. It's constantly saving and recalling what it was doing just prior to processing your last packet. No real work is getting done.

Vendors quickly realized that unless they wanted to wait for processor and bus speeds to catch up, they wouldn't sell many cards. They needed a solution that would allow their products to work on the slower processors available at that time. Jumbo frames provided one such solution.

Rather than moving data in 1500 byte chunks, they allowed their cards to use much larger packets. Some vendors supported 16384 bytes, others supported smaller numbers. The "de facto" standard was 9000 bytes.

At 9000 bytes per frame, the packet processing load is reduced by a factor of 6 (13,888 packets per second). The CPU has 1/6th the number of headers to process and theoretically, 1/6th the number of interrupts to handle.

Today, all but the very cheapest switches support jumbo frames and switch ports for Gigabit are well under $100 per port. This makes it extremely easy and economical to create a dedicated jumbo frame network.

Benefits

1. Having a separate network means less bandwidth contention for critical operations like captures or online editing.

2. Jumbo frames allow local systems to have more CPU cycles available for things like Final Cut Pro, improving the users experience running the application.

3. A jumbo frame network can support a larger class of systems including Apple Macbook, Macbook Pros, Mac Minis and iMacs.

4. Jumbo frames can be used to access "storage over Ethernet" devices like iSCSI and AoE RAIDS, such as those designed by companies like 2 Degrees Frost. These products eliminate typical bottlenecks found in client/server networks.

Conclusion

Having extra Gigabit ports on your machines makes using jumbo frames easier than ever and the benefits are tremendous. All small video capture and post houses, audio and pre-press shops should consider this simple, elegant solution to improve their network without breaking the bank.


Steve Modica is the Chief Technical Officer of Small Tree Communications. Mr. Modica brings over 15 years of experience in the field of high performance operating systems to the company. Prior to founding STC, he worked at Silicon Graphics Inc. managing a group of device driver engineers and managing third party vendor relationships. For the four years prior to joining SGI, he owned and operated HPC Consulting; a company specialized in customizing corporate networks. Mr. Modica attended Wayne State University in Detroit on a Merit Scholarship and received his degree in Electrical Engineering in 1992.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

1Password 6.6.1 - Powerful password mana...
1Password is a password manager that uniquely brings you both security and convenience. It is the only program that provides anti-phishing protection and goes beyond password management by adding Web... Read more
Safari Technology Preview 10.2 - The new...
Safari Technology Preview contains the most recent additions and improvements to WebKit and the latest advances in Safari web technologies. And once installed, you will receive notifications of... Read more
Eye Candy 7.2.0.50 - 30 professional Pho...
Eye Candy renders realistic effects that are difficult or impossible to achieve in Photoshop alone, such as Fire, Chrome, and the new Lightning. Effects like Animal Fur, Smoke, and Reptile Skin are... Read more
Microsoft Office 2016 15.31 - Popular pr...
Microsoft Office 2016 - Unmistakably Office, designed for Mac. The new versions of Word, Excel, PowerPoint, Outlook and OneNote provide the best of both worlds for Mac users - the familiar Office... Read more
Spotify 1.0.49.125. - Stream music, crea...
Spotify is a streaming music service that gives you on-demand access to millions of songs. Whether you like driving rock, silky R&B, or grandiose classical music, Spotify's massive catalogue puts... Read more
QuickBooks 16.1.12.1564 R13 - Financial...
QuickBooks helps you manage your business easily and efficiently. Organize your finances all in one place, track money going in and out of your business, and spot areas where you can save. Built for... Read more
Dash 4.0.1 - Instant search and offline...
Dash is an API documentation browser and code snippet manager. Dash helps you store snippets of code, as well as instantly search and browse documentation for almost any API you might use (for a full... Read more
Tinderbox 7.0.0 - Store and organize you...
Tinderbox is a personal content management assistant. It stores your notes, ideas, and plans. It can help you organize and understand them. And Tinderbox helps you share ideas through Web journals... Read more
Apple Remote Desktop Client 3.9 - Client...
Apple Remote Desktop Client is the best way to manage the Mac computers on your network. Distribute software, provide real-time online help to end users, create detailed software and hardware reports... Read more
Sparkle 2.1.1 - $79.99
Sparkle will change your mind if you thought building websites wasn't for you. Sparkle is the intuitive site builder that lets you create sites for your online portfolio, team or band pages, or... Read more

Tavern Guardians (Games)
Tavern Guardians 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Tavern Guardians is a Hack-and-Slash action game played in the style of a match-three. You can experience high pace action... | Read more »
Slay your way to glory in idle RPG Endle...
It’s a golden age for idle games on the mobile market, and those addictive little clickers have a new best friend. South Korean developer Ekkorr released Endless Frontier last year, and players have been idling away the hours in the company of its... | Read more »
Tiny Striker: World Football Guide - How...
| Read more »
Good news everyone! Futurama: Worlds of...
Futurama is finding a new home on mobile in TinyCo and Fox Interactive's new game, Futurama: Worlds of Tomorrow. They're really doing it up, bringing on board Futurama creator Matt Groening along with the original cast and writers. TinyCo wants... | Read more »
MUL.MASH.TAB.BA.GAL.GAL (Games)
MUL.MASH.TAB.BA.GAL.GAL 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: ENDLESS UPGRADES. CONSTANT DANGER. ANCIENT WISDOM. BOUNCY BALLS. Launch Sale, 40% OFF for a very limited time!!! MUL.... | Read more »
Dungeon Rushers (Games)
Dungeon Rushers 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dungeon Rushers is a 2D tactical RPG combining dungeon crawler’s gameplay and turn based fights. Manage your team, loot dusty... | Read more »
Blasty Bubs is a colorful Pinball and Br...
QuickByte Games has another arcade treat in the works -- this time it's a mishmash of brick breaking and Pinball mechanics. It's called Blasty Bubs, and it's a top down brickbreaker that has you slinging balls around a board. [Read more] | Read more »
Corsola and Heracross are the new region...
Generation 2 finally launched in Pokémon GO, unleashing a brand new batch of Pokémon into the wild. Even before the update went live people were speculating on how to catch elusive Pokémon like the legendary "dogs", Unknown, and whether or not... | Read more »
The Warlock of Firetop Mountain (Games)
The Warlock of Firetop Mountain 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: An epic adventure through a mysterious mountain filled with monsters, magic and mayhem! “...it looks downright... | Read more »
Fantasy MMORPG MU Origin’s receives a hu...
Developer Webzen are looking to take their highly popular fantasy battler MU Origin to the next level this month, with its most ambitious overhaul yet. The latest update introduces the long sought after Server Arena, new treasure dungeons, and much... | Read more »

Price Scanner via MacPrices.net

Apple restocks refurbished 11-inch MacBook Ai...
Apple has Certified Refurbished 11″ MacBook Airs (the latest models recently discontinued by Apple), available for up to $170 off original MSRP. An Apple one-year warranty is included with each... Read more
Apple Park Opens to Employees in April With T...
Apple has announced that Apple Park, the company’s new 175-acre campus, will be ready for employees to begin occupying in April. The process of moving more than 12,000 people will take over six... Read more
Manhattan Neighbors for Safer Telecommunicati...
A new education and advocacy group focused on cell phone and wireless risks, Manhattan Neighbors for Safer Telecommunications, launched today at http://www.ManhattanNeighbors.org. Manhattan... Read more
Portable Dual DisplayPort Monitor Dock Enable...
IOGEAR has announced the launch of its USB-C Dual DisplayPort Monitor Portable Dock (GUC3CMST). The dock enables users to easily connect two DisplayPort monitors to a USB-C or Thunderbolt 3 laptop to... Read more
13-inch 2.7GHz Retina MacBook Pro on sale for...
Amazon.com has restocked the 13″ 2.7GHz/128GB Retina MacBook Pro (MF839LL/A) for $200 off MSRP including free shipping: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1099 $200 off MSRP This model tends to... Read more
Apple’s New iPad Ads Don’t Address Pro Users’...
Apple launched a new tranche of iPad Pro TV ads last week addressing actual queries and challenges from the Twitterverse, albeit using actors for the visuals. That’s great. As an iPad fan and heavy... Read more
Free Verbum Catholic Bible Study App For iOS
The Verbum mobile app runs on Logos’ powerful Bible software and is an advanced resource for mobile Catholic study. The Verbum app surrounds the Bible with the Tradition. Verbum comes with 15 free... Read more
27-inch Apple iMacs on sale for up to $200 of...
B&H Photo has 27″ Apple iMacs on sale for up to $200 off MSRP, each including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2099.99 $200 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $... Read more
15-inch 2.2GHz Retina MacBook Pro on sale for...
Amazon has 2015 15″ 2.2GHz Retina MacBook Pros (MJLQ2LL/A) available for $1849.99 including free shipping. Apple charges $1999 for this model, so Amazon’s price is represents a $150 savings. Read more
Apple refurbished iPad Air 2s available start...
Apple has Certified Refurbished iPad Air 2 WiFis available for starting at $319 including free shipping. A standard Apple one-year warranty is included: - 16GB iPad Air 2 WiFi: $319 $60 off original... Read more

Jobs Board

Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.