Quote:
Originally Posted by muddly001
Sorry, lost me there totally! Could you explain that in lay persons language?
Regards
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Gee - if I was a layperson I might be able to...
however I'll give it a stab - just re-post if it's still not crystal? Assuming all of it was unclear:
For many (mainly historical) reasons many cable ISP's limited the MAC address (unique factory assigned id) of the network interface card of the equipment connected(reistered) to the cable modem. On domestic service (and specifcally with VM) the connection is limited to 1 device. (as typically defined by "cpe_max" stanza in the CM configuration file downloaded from TFTP server during CM reboot sequence)
When you reboot the CM then the MAC addy will be interogated and compared to a "mac bridging table"..... if it's changed then a re-registration process is required which may also additionally change your IP.
In the old NTL/TW/BY days different franchises had somewhat different ways of doing this ....from allowing so many changes in a set time period to actually requiring customer to contact ISP...
VM have attempted to automate (or correlate the different frot ends of) this process recently (within last 18 months) to minimise this incovenience, however occasionally authentication servers do "cough" and you can (albeit rarely) sometimes find yourself in a restricted "Walled garden" with a web page requiring you submit a userid/account number and password that NTL/TW/BY sent to you on your welcome pack a decade or so previous. Thus you only have limited access to VM servers but not the rest of Internet.!!
(In fact on corporate LANs MAC address's were often similarly used for security)
To avoid this (as problem affected many cable ISP's worldwide) then most (but not all) router manufacturers began incorporating firmware over the years that allowed the NIC MAC on the WAN side to be changed (or cloned).
The idea being if you originally registered with your ISP using a specific PC (with it's unique MAC) then you could "clone" that MAC address onto the WAN port of the replacement router. Almost virtually giving you a "hot replacement" facility (but not quite<g>). The CM would still be addressing the same MAC address at the lower physical media level of the ISO stack and and essentially would not be able to detect any difference.
Unfortunately (for reasons debated ad nauseam over the years) Apple Airports Express/Extreme (utilised within a TC) etc have not included this functionality!. AFAIK they haven't' yet produced hardware/firmware version to provide this either - but who knows in the future?.....
Now if VM's "auto-registration" process works as intended this should only be a minor (almost seamless) inconvenience.
However if like me you do get involved in the rare occasional "hiccups" that requires temporarily removing a router and cabling a PC/workstation to CM directly to diagnose an intermittent problem then you should be aware of this limitation.
If like me you don't suffer fools gladly then you won't tolerate some undertrained idiot in Mumbai telling you to reboot your modem because it potentially will promptly overwrite (wrap) some or all the existing error logs...thus loosing valuable forensics as the CM goes thru it's cold start/re-IPL initialisation process.
Hope this clarifies a little better...