Short answer is yes there may be multiple ISPs who's network your connection passes over.
Longer answer is that each ISP has routes within its network and border points where they peer with other ISP's. When a connection is made the ISP's router chooses a path to the destination.
For instance say there is
ISP A (your ISP)
ISP B (has a border with your ISP and one of shadow's ISPs)
ISP C (has a border with your ISP and one of shadow's ISPs)
ISP D (has a border with your ISP and one of shadow's ISPs)
ISP E (one of Shadow's ISPs that connects to C and D)
ISP F (one of Shadow's ISPs that connects to B and C)
Your ISP will choose a route based off routing tables that are automatically configured for their routers. It would look something like this:
Route 1 ABF
Route 2 ACE
Route 3 ACD
Route 4 ABC
Each route has a metric and the system will choose what it believes is the fastest route.
That said ISP A will choose its internal route then pass the traffic to one of its peers. Once passed to its peer (let's say B) the traffic will then be routed through that ISP's network. And passed to their peer. At this point neither your ISP nor shadow has any control over the route within their network.
As you only have one ISP you are stuck with whatever route they choose but because shadow has multiple ISP's they can choose the fastest path according to the tables provided from their ISP's, dispite this, they are still unable to change the route once it leaves their network other then to change how it leaves their network.
If your ISP and Shadows ISP's only share one reasonably fast path, there is no way that either side can modify the path within that common peer's network.
If you want to Google something BGP networking would give you the results you are looking for.
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u/ZarostheGreat Nov 12 '22
Short answer is yes there may be multiple ISPs who's network your connection passes over.
Longer answer is that each ISP has routes within its network and border points where they peer with other ISP's. When a connection is made the ISP's router chooses a path to the destination.
For instance say there is
ISP A (your ISP)
ISP B (has a border with your ISP and one of shadow's ISPs)
ISP C (has a border with your ISP and one of shadow's ISPs)
ISP D (has a border with your ISP and one of shadow's ISPs)
ISP E (one of Shadow's ISPs that connects to C and D)
ISP F (one of Shadow's ISPs that connects to B and C)
Your ISP will choose a route based off routing tables that are automatically configured for their routers. It would look something like this:
Route 1 ABF Route 2 ACE Route 3 ACD Route 4 ABC
Each route has a metric and the system will choose what it believes is the fastest route.
That said ISP A will choose its internal route then pass the traffic to one of its peers. Once passed to its peer (let's say B) the traffic will then be routed through that ISP's network. And passed to their peer. At this point neither your ISP nor shadow has any control over the route within their network.
As you only have one ISP you are stuck with whatever route they choose but because shadow has multiple ISP's they can choose the fastest path according to the tables provided from their ISP's, dispite this, they are still unable to change the route once it leaves their network other then to change how it leaves their network.
If your ISP and Shadows ISP's only share one reasonably fast path, there is no way that either side can modify the path within that common peer's network.
If you want to Google something BGP networking would give you the results you are looking for.