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Airport Extreme with Gigabit Ethernet - Does it have jumbo frame support?

Please, can I get definite answer to this question? I do not need speculations as I read some reviews already. Can we have Apple finally put complete specification of the product rather than "popular one" with attachement of protocol numbers?

I just need simple answer possibly from Apple engineering team to the following questions:

1. Does current Airport Extreme have support for jumbo frames (everything above 1500bytes per frame)? (if one does not know what that is them perhaps understanding acronym "MTU" can help a bit)
2. If there is support then what is the maximum supported size of jumbo frame? (Some products do not go above 6k and I read some statistics that traffic somwhere is usually 66% at about 4k jumbo frames and above that there is not much...)
3. If there is no support then does Apple plan on update for this (firmware or hardware) in the future?

Please, do not tell me that someoene ran something with jumbo frame and it worked as I tried yesterday LaCie Ethernet drive with supposedly setup (I set it myself) of jumbo frame 4k and on soft reboot of the drive it worked when connected to Airp[ort Extreme, but after hard reboot the disk is not visible anymore. I will recover the disk, but I need to understand if I have chance of using jumbo frames that tremendously improve performance with large files (e.g. try movies stored for AppleTV on network drive) when using Airport Extreme with its gigabit Ethernet... or that is just Gigabit Ethernet for product marketing purposes only.

I just need reliable answer by product specification that should be on paper at Apple, but it is not so I hope that one of guys here has access to some engineering team.


Thank you,
Maciek Samsel

PowerMac G4 (dual), Intel Core Duo Mac Mini, Mac OS X (10.4.5), Dell 2005FPW, Logitech trackball, External DVD-ROM Region Free...

Posted on Nov 6, 2007 6:53 AM

Reply
5 replies

Nov 11, 2007 8:42 AM in response to Maciej Samsel

Thanks for lack of interest in this important issue that is known for anybody who actually works with gigabit networks.

Now I tested myself MTU sizes with Airport Extreme for n networks on its wired ports. Yes it seems to support jumbo frames finally in this release. If you need to know what size is maximum I can give you the number, but since the interest in the issue is so low I am not going to pulish it. Appple should do it.

Thanks,
Maciek

Nov 11, 2007 3:46 PM in response to Maciej Samsel

The spec. on the chip used by Apple support your conclusion.

BCM5395 Features
Complies with IEEE802.3, IEEE802.3u, IEEE802.3ab standards
5 10/100/1000Mbps Auto-Sense RJ45 ports supporting Auto-MDI/MDIX
All ports Support Full/Half Duplex transfer mode for 10/100Mbps and Full Duplex transfer mode for 1000Mbps
Port-based and MAC-based VLAN
IEEE 802.1Q-based VLAN with 4K entries
Port-based rate control
Port mirroring
Compact field processor (CFP)
512 rules
Filtering, classifications, remarking, and priority actions.
Priority modification on egress
DOS Attack Prevention
Loop detection for unmanaged configurations with Broadcom’s patented LoopDTech™ technology
CableChecker™ with unmanaged mode support
Double tagging
IEEE 802.3x programmable per-port flow control and back pressure, with IEEE 802.1x support for secure user authentication
4K entry MAC address table with automatic learning and aging
128-KB packet buffer
128 multicast group support
Jumbo Frame support up to 9728 byte

Nov 12, 2007 8:36 AM in response to Ein

Could not find that last line on any specs I saw for Airport Extreme. Especially when find in browser cannot find the word "Jumbo"

http://www.apple.com/airportextreme/specs.html


Also I believe that Apple states wrong number. Correct size number is rather 8182. Everything above that will bring error (and yes my switch supports much larger "jumbo frames" as most modern switches do).


Thanks,
Maciek

Airport Extreme with Gigabit Ethernet - Does it have jumbo frame support?

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