Identical mac addresses in the provider's network?

Question

Computer networks

The question is both theoretical and practical at the same time. What happens if there are 2 devices with the same MAC addresses in the same provider network but not in the same house (one switch)? Does the poppy address affect only at the level of the switch in the house or at the level of the entire provider? Or does it depend on the specific provider and its network device? If we take options as an example (they are probably arranged differently in each city, but I will give an example as in ours):
1. The Rostelecom dhcp network is tied to a poppy (the system inserted a cable and the Internet appeared)
2. Beeline network, local ip is issued via dhcp + l2tp (on a port of 5 poppy addresses, it is especially interesting how in this case if there are not the same poppy but different but the same in the port memory with what works on another house, a typical example is a laptop and we go to visit a neighboring house, enter the name and password on l2tp there, it turns out that at home the poppy will not be active on the port, but at the party the poppy will be active how will it work? poppy will be removed from the port from the house and registered in another place?) .
3. The network is home ru / mts, there seems to be no binding to the poppy, everything works right away as you enter the name and password pppoe on the interface does not issue any local addresses.
Now a practical question, it so happened that I sewed the poppy address of the computer into the router that even when resetting it restores it, now I decided to abandon the router and connected everything directly, I decided to give the router to my nephew, he has the same provider that I have but lives on another street , if we have the same poppy on the network, will there be conflicts in the network? Simply put, is the poppy globally visible on the network or only at the switch level in the house?

Answer 1

What's stopping you from plugging in and checking? It is unlikely that now one of the employees of your provider with the help of a magic ball found out that you are their client and will tell you how their network will work.
And even if I had found out, I most likely would not have been able to answer unambiguously either, and what prevents the native poppy from being sewn back to the router in the same way as the computer's poppy?

Answer 2

Problems can arise if cards with the same MAC address are in the same network segment (not separated from each other by a router). There will be ARP collisions on L2, and the switch is unlikely to be able to correctly understand which port to send traffic to for a specific mac address. Well, in particular, there will be problems with dhcp (one IP address will be allocated to one poppy).

Answer 3

mac works within a segment limited by routers
; there will be problems if the switch is not smart (xs, are there any left), such as a "hub" and two links with the same poppies at the end are inserted into it,
and the poppy works much more often than you think: think about how much client provider and what pool of real IPs - how does the wire deal with routing
in short - you don’t have to worry
about another thing, that in SORM, perhaps, this will not be happy))) renegotiate the contract)

Answer 4

And tell me how the network behaves by default if, conditionally, correspondences to 5 poppy addresses are recorded on one port (in the beeline, because iptv set-top boxes are connected there through a switch) and 1 is used at the same time and the remaining 4 are connected at the same time in the same network in the same network segment, an example connected to the beeline and installed 2 set-top boxes, the client does not like it and these 2 set-top boxes are carried away to connect to a neighboring house, the entries on the port of the first client are overwritten immediately or remain hanging and this does not interfere until they are active? Or, when connecting to any network, to check, the master connected his laptop, the entry on the port remained, then he goes to a neighboring house and connects his laptop already there, inactive poppy recorded on the port affect the network?
And it’s interesting, there are networks still linked to a poppy, in order to reconnect it’s not enough to go to the personal account, you have to call and hang on the line for half an hour (it was a local provider and they didn’t work after 17.00 to 9.00 and on weekends) so many just they prescribe it (everyone did this when buying a router or updating mp, even on a local forum they wrote that don’t mess with our brains, but write it yourself), and these routers stood for years later and iron with this poppy was then sold at a local flea market on the same forum, why didn’t it arise problems? Because everyone was prescribing their old poppies?
And maybe someone else knows the question, why in the same beeline, if the device has been standing for a long time, then dhcp issues a local ip for a week, but if you put a new device, then the ip is only for an hour and how is this related to the poppy?

Answer 5

As far as I remember, if the switch is smart, then the poppy is attached to the PORT of the switch. Hence there are no problems in other places
As for the beeline - yes, hell knows how the network is arranged. Most likely this was done for the tuners - he came, extended the cable, plugged in his laptop, checked the network. the Internet. Then I plugged it into the client's router, if there is one, of course))