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AW: [lwip-users] Connect several boards EVK1100


From: Mathias Zenger
Subject: AW: [lwip-users] Connect several boards EVK1100
Date: Wed, 3 Feb 2010 07:25:47 +0100

Obviousely some of my statements were pretty wrong. Sorry! Thanks for correcting me and for the perfect information David.
-----Ursprüngliche Nachricht-----
Von: David Empson [mailto:address@hidden
Gesendet: Dienstag, 2. Februar 2010 23:24
An: address@hidden; Mailing list for lwIP users
Betreff: Re: [lwip-users] Connect several boards EVK1100

Mathias Zenger wrote:
Usually you need to obtain your own MAC addresses at IANA (your own OUI costs about $160).
I can't see any mention of OUIs or MAC addresses at IANA.
 
The official registry for allocating MAC addresses is run by IEEE, and no other organisation is allowed to on-sell them.
 
 
It costs US$1650 to register an OUI, which reserves 16 million MAC addresses permanently for your use. (This is a one-off fee.) If you don't want your allocation listed in the public registry there is an additional annual fee of US$2000.
 
You can also register an individual address block for US$550, which reserves 4096 MAC addresses permanently for your use. (This is a one-off fee.) If you don't want your allocation listed in the public registry there is an additional annual fee of US$1000.
 
If you are eventually going to need more than 12000 MAC addresses, it is cheaper to get an OUI.
 
You need to do either of these before your device can be sold or connected to anyone else's network (except in limited testing situations).
 
The only other semi-legitimate way to get a small number of MAC addresses would be to get hold of sufficient existing Ethernet devices, note down their MAC addresses and then destroy them or at least ensure they are never connected to a network.
 For testing purposes in your private network you probably just can vary
 
ETHERNET_CONF_ETHADDR0..5
 
and
 
ETHERNET_CONF_IPADDR0..3
It is also worth mentioning that there is a range of MAC addresses specifically reserved for local administration, which can be useful for testing purposes. Their intended purpose is to allow a network administrator to allocate their own private MAC address to every device on the network, rather than using the manufacturer-supplied MAC address. In practice I doubt this is used much.
 
This means that the locally administered MAC address range is very likely to be free for your own use within your network, but you can't use it with devices that you are supplying for use on other networks. You should check with your network administrator before using this MAC address range.
 
See http://standards.ieee.org/regauth/groupmac/tutorial.html for details, but in short, if you start the MAC address with 0x40 in the first octet (MSB first) it is a locally administered address and is guaranteed to not conflict with any universally administered MAC address (one assigned by a hardware manufacturer).
 

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