what about 48 bits?
Hi, Lots of traffic recently about 64 bits being too short or too long. What about mac addresses? Aren't they close to exhaustion? Should be. Or it is assumed that mac addresses are being widely reused throughout the world? All those low cost switches and wifi adapters DO use unique mac addresses?
Re: what about 48 bits?
2010/4/4 Scott Howard sc...@doc.net.au On Sun, Apr 4, 2010 at 1:51 PM, Matthew Kaufman matt...@matthew.at wrote: http://en.wikipedia.org/wiki/MAC_address The IEEE expects the MAC-48 space to be exhausted no sooner than the year 2100[3]; EUI-64s are not expected to run out in the foreseeable future. And this is what happens when you can use 100% of the bits on endpoint identity and not waste huge sections of them on the decision bits for routing topology. Having around 4 orders of magnitude more addresses probably doesn't hurt either... Although even MAC-48 addresses are wasteful in that only 1/4 of them are assignable to/by vendors, with the other 3/4 being assigned to multicast and local addresses (the MAC equivalent of RFC1918) Scott. Wasteful in many ways. While most of end user devices work with temporarily assigned IP addresses, or even with RFC1918 behind a NAT, very humble ethernet devices come from factory with a PERMANENTE unique mac address. And one of those devices are thrown away – let’s say a cell phone with wifi, or a cheap NIC PC card - the mac address is lost forever. Doesn’t this sound not reasonable? A.b. --
BER performance on fiber links
Hi all, What is the bit error rate that can be expected from a modern hi capacity mostly optical point to point circuits ? 10 E-7 would be too conservative or too agressive? What if the circuit is in fact Ethernet LAN to LAN transport? How many frames can one expect to be discarded due to link errors? Thank you in advance. A.B.
Re: Restrictions on Ethernet L2 circuits?
Linen, As far as I'm concerned, enterprises should just connect their various sites to the Internet independently, and use VPN techniques if and where necessary to provide the illusion of a unified network. In practice, this illusion of a single large LAN (or rather, multiple organization-wide LANs) is very important to the typical enterprise, because so much security policy is enforced based on IP addresses. And the typical enterprise wants a central chokepoint that all traffic must go through, for reasons that might have to do with security, or support costs, or with (illusions of) control. Most security policies are also based on 'local vs remote criteria. Most pieces of software believe that an access to a local IP is faster and safer than accesses to an IP address somewhere else. Emulate means lying to someone, and if you start lying too much you can end up messing everything. I agree that enterprises should use WANs as WANS (i.e., IP routed networks) and don't try to hide distance and security fragility from systems and security appliances. End to end VPN can be used in the very special cases where a special security is needed, by means of strong VPN encryption. It seems nice to have something that looks like a simple Ethernet cable. The problem is that it is *not* a simple cable, and will never be. Make the rest of the LAN believe that it is such a simple cable may raise huge trouble. Most of LAN protocols have a degree of TRUST on LAN traffic. Any security expert will tell you that trust is your enemy. Managing a router is a hassle? Oh, come on! If a net admin is unable to manage a simple sub net configuration and so some simple math with masks and prefixes he would rather find himself another job. Take care, A.B. Jr.
