Identical mac addresses in the provider network?

Question and theoretical and practical at the same time. What would happen if one network provider but not in the same house (one switch) are 2 devices with the same Mac addresses? Mac address controls only at the level of the switch in the house or on the provider? Or depends on the specific provider and its network devices? If you take for example the options (arranged probably in every city in different ways but I will give the example as in our):
1. The network of Rostelecom dhcp is bound to the Mac (the system inserted the cable and Internet there)
2. The network Beeline, the local ip issued via dhcp+l2tp(on port 5 Mac addresses stored particularly interesting in this case is not the same Mac as different but the same memory port that operates at a different house, a typical example take the laptop and go to visit the house next door there enter the name and password for l2tp, it turns out that my home Mac is not active on a port where a Mac as active as it could be? Mac will be removed from the port from home and will be prescribed in a different place?).
3. Network Dom ru/MTS, binding to Mac it seems not everything works as soon as you enter the name and password on pppoe interface no local address is not given.

Now a practical question, it so happened that I stitched the Mac address of the computer in the router that he even resetting it restores, now decided to unsubscribe from the router and connected all on the line, the router decided to give to my nephew, he has the same ISP that I have but live in a different street, if we in a network have the same Mac will not have any collisions on the network? Simply put Mac is globally visible in the network or only switch in the house?
April 3rd 20 at 18:27
5 answers
April 3rd 20 at 18:29
And what prevents to stick Yes check? Now hardly someone from employees of your provider with the help of a magic ball he learned that you are their client and say how to work their network.
And even if I found out it is likely too could not answer, and what prevents to sew up the router's native Mac back by the same method that Mac computer?
Well, I wrote that the question is theoretical, just wondering. - kaleb.Bartell15 commented on April 3rd 20 at 18:32
@kaleb.Bartell15,
Question and theoretical and practical at the same time.

So check in practice. Really beat you, no one will - Alfonzo_MacGyv commented on April 3rd 20 at 18:35
April 3rd 20 at 18:31
Problems can arise if cards with the same MAC addresses are in the same network segment (not shielded from each other by the router). On L2 there are collisions in the ARP, and the switch is unlikely to be able to properly understand which port to send traffic from specific mac addresses. And, in particular, dhcp will be a problem (one big Mac will be allocated a single IP address).
the switch will understand: at first, before the restructuring arp table - Lamar_Becker4 commented on April 3rd 20 at 18:34
April 3rd 20 at 18:33
Mas working within a segment bounded by routers

the problem will be if the switch is not smart (XS, whether there were such), type "hub" and stuck two links with odinakovymi poppies at the end

and Mac works more often than it seems: think of how many provider clients, and which pool of real IP as the wiring to cope with the routing

in short - don't bother

another thing is that SORM, perhaps, would not be happy.))) renew the contract )
April 3rd 20 at 18:35
And tell me how the default behavior of the network if conditional on one port recorded compliance 5 Mac addresses (Beeline so due to the fact that there is a switch connected iptv boxes) at one time is 1 and the remaining 4 at this time are connected to the same network in the same network segment, the sample was connected to the Beeline and installed 2 consoles, I like these 2 consoles carry on connection to a nearby house, write on a port the first client is immediately overwritten or remain hanging and it does not stop until they are active? Or when you connect to any network to verify the master had hooked his laptop, write on a port is left, then he goes to a nearby house and connects his laptop already there, dormant Mac written to the port affect the operation of the network?
And interestingly, there are still bound to the Mac to perepryatat enough to go to BOS, we have to call and hang on the line for half an hour (it was a local provider and they did not work after 9.00 to 17.00 and at weekends) so many people simply prescribe (so did all, when buying a router or upgrading MP even on my local forum wrote that do not worry us, the brain and prescribe themselves), and these routers were years and then iron with this Mac was sold later at the local flea market in this same forum why not have any problems? Because all prescribed his old Mac?
And maybe someone knows another question, why in the same Beeline if there is a device long ago that dhcp gives out a local ip for a week, but if you put a new device then the ip only on the hour and how it relates to Mac?
April 3rd 20 at 18:37
As I recall, if the switch is smart - it attached Mac PORT of the switch. Hence no problem in other places
About Beeline - who the hell knows how the network is arranged. This is most likely done for the Adjusters came, stretched cable, stuck my laptop, checked the network. the Internet. Then peridol in the router client, unless of course he is))

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