To what extent can ISPs control routing in a packet-switched network?
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As an application developer my entire understanding of networks was a high level 'acceptance' of http request/response pairs along with some DNS addressing.
Somewhere in the back of my mind I understood that HTTP was built on top of TCP and that TCP packets need to be routed across networks, and that the routing of these packets can vary. I have never, until now, considered the complexity that must be present in routing packets via 'hops' from origin/destination.
How much control do ISPs and other entities have over this process? i.e. my understanding is that an ISP can conceptually be seen as a destination within a multi-hop route - does an ISP have the ability/authority to decide on the next destination of a particular packet? If so, how is this controlled?
routing network traffic-engineering
asked Sep 5 at 8:26
Zach Smith
22628
add a comment |Â
up vote
1
down vote
favorite
As an application developer my entire understanding of networks was a high level 'acceptance' of http request/response pairs along with some DNS addressing.
Somewhere in the back of my mind I understood that HTTP was built on top of TCP and that TCP packets need to be routed across networks, and that the routing of these packets can vary. I have never, until now, considered the complexity that must be present in routing packets via 'hops' from origin/destination.
How much control do ISPs and other entities have over this process? i.e. my understanding is that an ISP can conceptually be seen as a destination within a multi-hop route - does an ISP have the ability/authority to decide on the next destination of a particular packet? If so, how is this controlled?
routing network traffic-engineering
asked Sep 5 at 8:26
Zach Smith
22628
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
As an application developer my entire understanding of networks was a high level 'acceptance' of http request/response pairs along with some DNS addressing.
Somewhere in the back of my mind I understood that HTTP was built on top of TCP and that TCP packets need to be routed across networks, and that the routing of these packets can vary. I have never, until now, considered the complexity that must be present in routing packets via 'hops' from origin/destination.
How much control do ISPs and other entities have over this process? i.e. my understanding is that an ISP can conceptually be seen as a destination within a multi-hop route - does an ISP have the ability/authority to decide on the next destination of a particular packet? If so, how is this controlled?
routing network traffic-engineering
asked Sep 5 at 8:26
Zach Smith
22628
As an application developer my entire understanding of networks was a high level 'acceptance' of http request/response pairs along with some DNS addressing.
Somewhere in the back of my mind I understood that HTTP was built on top of TCP and that TCP packets need to be routed across networks, and that the routing of these packets can vary. I have never, until now, considered the complexity that must be present in routing packets via 'hops' from origin/destination.
How much control do ISPs and other entities have over this process? i.e. my understanding is that an ISP can conceptually be seen as a destination within a multi-hop route - does an ISP have the ability/authority to decide on the next destination of a particular packet? If so, how is this controlled?
routing network traffic-engineering
routing network traffic-engineering
asked Sep 5 at 8:26
Zach Smith
22628
asked Sep 5 at 8:26
Zach Smith
22628
asked Sep 5 at 8:26
Zach Smith
22628
asked Sep 5 at 8:26
Zach Smith
22628
asked Sep 5 at 8:26
Zach Smith
22628
22628
add a comment |Â
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
4
down vote
accepted
TCP in turn runs on top of IP which is then routed from the source to the destination host.
The routing of each packet is a local decision which is entirely up to the forwarding router. This routing decision is controlled by the local routing table and possible policies imposed by its administrator (based on source IP, protocol, transport-layer ports, tags, bandwidth, load, QoS, ...).
So, an ISP has total control over what their routers do. The same is true for anyone else controlling routers along the path (carriers, IX operators, your local network admin).
Technically, it's totally possible that anyone controlling a router on your path decides to route and terminate packets "somewhere else". Therefore, it's essential that routers and other important infrastructure components (switches, DNS servers, ...) are kept very safe.
answered Sep 5 at 8:42
Zac67
20.2k21047
does that mean that it's at least theoretically possible that my request reaches a router, and then instead of forwarding my request to that address - say chase.com - instead forwards my request to a server on their local network that is setup with a hostname of 'chase.com'?
– Zach Smith
Sep 5 at 8:52
Theoretically, yes. Routing is based on IP addresses though but an admin (or attacker) could route the destination IP to another server (directly, NATed, through tunneling) or manipulate DNS so you end up on a totally different IP address.
– Zac67
Sep 5 at 9:53
add a comment |Â
up vote
3
down vote
ISPs connect between them directly or using IXPs. The routers use a protocol to exchange information about the networks they are connected to and some of their features as speed and latency.
The routers store that information as a routing table, so when an IP packet comes, it checks the routing table and decides through which interface it will forward the packet.
For example, a user connecting to YouTube from an Access ISP will be routed to its destination through Regional or Global ISPs because they have lower latency and higher speeds than any other Access ISP.
answered Sep 5 at 9:02
jcbermu
3,848817
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
accepted
TCP in turn runs on top of IP which is then routed from the source to the destination host.
The routing of each packet is a local decision which is entirely up to the forwarding router. This routing decision is controlled by the local routing table and possible policies imposed by its administrator (based on source IP, protocol, transport-layer ports, tags, bandwidth, load, QoS, ...).
So, an ISP has total control over what their routers do. The same is true for anyone else controlling routers along the path (carriers, IX operators, your local network admin).
Technically, it's totally possible that anyone controlling a router on your path decides to route and terminate packets "somewhere else". Therefore, it's essential that routers and other important infrastructure components (switches, DNS servers, ...) are kept very safe.
answered Sep 5 at 8:42
Zac67
20.2k21047
does that mean that it's at least theoretically possible that my request reaches a router, and then instead of forwarding my request to that address - say chase.com - instead forwards my request to a server on their local network that is setup with a hostname of 'chase.com'?
– Zach Smith
Sep 5 at 8:52
Theoretically, yes. Routing is based on IP addresses though but an admin (or attacker) could route the destination IP to another server (directly, NATed, through tunneling) or manipulate DNS so you end up on a totally different IP address.
– Zac67
Sep 5 at 9:53
add a comment |Â
up vote
4
down vote
accepted
TCP in turn runs on top of IP which is then routed from the source to the destination host.
The routing of each packet is a local decision which is entirely up to the forwarding router. This routing decision is controlled by the local routing table and possible policies imposed by its administrator (based on source IP, protocol, transport-layer ports, tags, bandwidth, load, QoS, ...).
So, an ISP has total control over what their routers do. The same is true for anyone else controlling routers along the path (carriers, IX operators, your local network admin).
Technically, it's totally possible that anyone controlling a router on your path decides to route and terminate packets "somewhere else". Therefore, it's essential that routers and other important infrastructure components (switches, DNS servers, ...) are kept very safe.
answered Sep 5 at 8:42
Zac67
20.2k21047
does that mean that it's at least theoretically possible that my request reaches a router, and then instead of forwarding my request to that address - say chase.com - instead forwards my request to a server on their local network that is setup with a hostname of 'chase.com'?
– Zach Smith
Sep 5 at 8:52
Theoretically, yes. Routing is based on IP addresses though but an admin (or attacker) could route the destination IP to another server (directly, NATed, through tunneling) or manipulate DNS so you end up on a totally different IP address.
– Zac67
Sep 5 at 9:53
add a comment |Â
up vote
4
down vote
accepted
up vote
4
down vote
accepted
TCP in turn runs on top of IP which is then routed from the source to the destination host.
The routing of each packet is a local decision which is entirely up to the forwarding router. This routing decision is controlled by the local routing table and possible policies imposed by its administrator (based on source IP, protocol, transport-layer ports, tags, bandwidth, load, QoS, ...).
So, an ISP has total control over what their routers do. The same is true for anyone else controlling routers along the path (carriers, IX operators, your local network admin).
Technically, it's totally possible that anyone controlling a router on your path decides to route and terminate packets "somewhere else". Therefore, it's essential that routers and other important infrastructure components (switches, DNS servers, ...) are kept very safe.
answered Sep 5 at 8:42
Zac67
20.2k21047
TCP in turn runs on top of IP which is then routed from the source to the destination host.
The routing of each packet is a local decision which is entirely up to the forwarding router. This routing decision is controlled by the local routing table and possible policies imposed by its administrator (based on source IP, protocol, transport-layer ports, tags, bandwidth, load, QoS, ...).
So, an ISP has total control over what their routers do. The same is true for anyone else controlling routers along the path (carriers, IX operators, your local network admin).
Technically, it's totally possible that anyone controlling a router on your path decides to route and terminate packets "somewhere else". Therefore, it's essential that routers and other important infrastructure components (switches, DNS servers, ...) are kept very safe.
answered Sep 5 at 8:42
Zac67
20.2k21047
answered Sep 5 at 8:42
Zac67
20.2k21047
answered Sep 5 at 8:42
Zac67
20.2k21047
answered Sep 5 at 8:42
Zac67
20.2k21047
20.2k21047
does that mean that it's at least theoretically possible that my request reaches a router, and then instead of forwarding my request to that address - say chase.com - instead forwards my request to a server on their local network that is setup with a hostname of 'chase.com'?
– Zach Smith
Sep 5 at 8:52
Theoretically, yes. Routing is based on IP addresses though but an admin (or attacker) could route the destination IP to another server (directly, NATed, through tunneling) or manipulate DNS so you end up on a totally different IP address.
– Zac67
Sep 5 at 9:53
add a comment |Â
does that mean that it's at least theoretically possible that my request reaches a router, and then instead of forwarding my request to that address - say chase.com - instead forwards my request to a server on their local network that is setup with a hostname of 'chase.com'?
– Zach Smith
Sep 5 at 8:52
Theoretically, yes. Routing is based on IP addresses though but an admin (or attacker) could route the destination IP to another server (directly, NATed, through tunneling) or manipulate DNS so you end up on a totally different IP address.
– Zac67
Sep 5 at 9:53
does that mean that it's at least theoretically possible that my request reaches a router, and then instead of forwarding my request to that address - say chase.com - instead forwards my request to a server on their local network that is setup with a hostname of 'chase.com'?
– Zach Smith
Sep 5 at 8:52
does that mean that it's at least theoretically possible that my request reaches a router, and then instead of forwarding my request to that address - say chase.com - instead forwards my request to a server on their local network that is setup with a hostname of 'chase.com'?
– Zach Smith
Sep 5 at 8:52
Theoretically, yes. Routing is based on IP addresses though but an admin (or attacker) could route the destination IP to another server (directly, NATed, through tunneling) or manipulate DNS so you end up on a totally different IP address.
– Zac67
Sep 5 at 9:53
Theoretically, yes. Routing is based on IP addresses though but an admin (or attacker) could route the destination IP to another server (directly, NATed, through tunneling) or manipulate DNS so you end up on a totally different IP address.
– Zac67
Sep 5 at 9:53
add a comment |Â
up vote
3
down vote
ISPs connect between them directly or using IXPs. The routers use a protocol to exchange information about the networks they are connected to and some of their features as speed and latency.
The routers store that information as a routing table, so when an IP packet comes, it checks the routing table and decides through which interface it will forward the packet.
For example, a user connecting to YouTube from an Access ISP will be routed to its destination through Regional or Global ISPs because they have lower latency and higher speeds than any other Access ISP.
answered Sep 5 at 9:02
jcbermu
3,848817
add a comment |Â
up vote
3
down vote
ISPs connect between them directly or using IXPs. The routers use a protocol to exchange information about the networks they are connected to and some of their features as speed and latency.
The routers store that information as a routing table, so when an IP packet comes, it checks the routing table and decides through which interface it will forward the packet.
For example, a user connecting to YouTube from an Access ISP will be routed to its destination through Regional or Global ISPs because they have lower latency and higher speeds than any other Access ISP.
answered Sep 5 at 9:02
jcbermu
3,848817
add a comment |Â
up vote
3
down vote
up vote
3
down vote
ISPs connect between them directly or using IXPs. The routers use a protocol to exchange information about the networks they are connected to and some of their features as speed and latency.
The routers store that information as a routing table, so when an IP packet comes, it checks the routing table and decides through which interface it will forward the packet.
For example, a user connecting to YouTube from an Access ISP will be routed to its destination through Regional or Global ISPs because they have lower latency and higher speeds than any other Access ISP.
answered Sep 5 at 9:02
jcbermu
3,848817
ISPs connect between them directly or using IXPs. The routers use a protocol to exchange information about the networks they are connected to and some of their features as speed and latency.
The routers store that information as a routing table, so when an IP packet comes, it checks the routing table and decides through which interface it will forward the packet.
For example, a user connecting to YouTube from an Access ISP will be routed to its destination through Regional or Global ISPs because they have lower latency and higher speeds than any other Access ISP.
answered Sep 5 at 9:02
jcbermu
3,848817
answered Sep 5 at 9:02
jcbermu
3,848817
answered Sep 5 at 9:02
jcbermu
3,848817
answered Sep 5 at 9:02
jcbermu
3,848817
3,848817
add a comment |Â
add a comment |Â
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