How does Linux actually perform protocol data unit (PDU) encapsulation?
I understand that as data goes from the upper layers (Application Layer) to the lower layers (Physical/Link Layer(s)), the data is encapsulated. When it goes back up the layers, it is decapsulated.
However, most articles about data encapsulation are very conceptual. What I want to know is how Linux actually perform en/decapsulation - what utilities are used? Or is it done by the kernel? If so, is it in the core, or some kernel modules?
To make potential answers more concrete, let's suppose we are talking about data that is sent from a Google Chrome web browser on a Linux machine to a remote API server. I assume the web browser is responsible for encapsulating the data into HTTP packets, but what is responsible for encapsulating the HTTP packet into a TCP segment, and then an IP datagram, and then the Ethernet frame (the network interface driver?)
I posted this on Network Engineering but it was deemed off-topic. I also considered posting this on Server Fault but think this SE site is the best fit.
linux networking kernel kernel-modules internet
asked 15 hours ago
dayulolidayuloli
226110
add a comment |
I understand that as data goes from the upper layers (Application Layer) to the lower layers (Physical/Link Layer(s)), the data is encapsulated. When it goes back up the layers, it is decapsulated.
However, most articles about data encapsulation are very conceptual. What I want to know is how Linux actually perform en/decapsulation - what utilities are used? Or is it done by the kernel? If so, is it in the core, or some kernel modules?
To make potential answers more concrete, let's suppose we are talking about data that is sent from a Google Chrome web browser on a Linux machine to a remote API server. I assume the web browser is responsible for encapsulating the data into HTTP packets, but what is responsible for encapsulating the HTTP packet into a TCP segment, and then an IP datagram, and then the Ethernet frame (the network interface driver?)
I posted this on Network Engineering but it was deemed off-topic. I also considered posting this on Server Fault but think this SE site is the best fit.
linux networking kernel kernel-modules internet
asked 15 hours ago
dayulolidayuloli
226110
Kernel. It happens that IP cannot be built as a loadable module (and TCP cannot be disabled separately from IP). CONFIG_INET is boolean - which means y/n only, cannot be set to "m". You don't suggest that this would make any difference for what you want to know though. It doesn't actually matter that much whether you load the code in separately or not. CONFIG_IP_SCTP is a tristate, so it can be set to "m". I don't see how that makes any difference to TCP v.s. SCTP en/decapsulation.
– sourcejedi
14 hours ago
add a comment |
I understand that as data goes from the upper layers (Application Layer) to the lower layers (Physical/Link Layer(s)), the data is encapsulated. When it goes back up the layers, it is decapsulated.
However, most articles about data encapsulation are very conceptual. What I want to know is how Linux actually perform en/decapsulation - what utilities are used? Or is it done by the kernel? If so, is it in the core, or some kernel modules?
To make potential answers more concrete, let's suppose we are talking about data that is sent from a Google Chrome web browser on a Linux machine to a remote API server. I assume the web browser is responsible for encapsulating the data into HTTP packets, but what is responsible for encapsulating the HTTP packet into a TCP segment, and then an IP datagram, and then the Ethernet frame (the network interface driver?)
I posted this on Network Engineering but it was deemed off-topic. I also considered posting this on Server Fault but think this SE site is the best fit.
linux networking kernel kernel-modules internet
asked 15 hours ago
dayulolidayuloli
226110
I understand that as data goes from the upper layers (Application Layer) to the lower layers (Physical/Link Layer(s)), the data is encapsulated. When it goes back up the layers, it is decapsulated.
However, most articles about data encapsulation are very conceptual. What I want to know is how Linux actually perform en/decapsulation - what utilities are used? Or is it done by the kernel? If so, is it in the core, or some kernel modules?
To make potential answers more concrete, let's suppose we are talking about data that is sent from a Google Chrome web browser on a Linux machine to a remote API server. I assume the web browser is responsible for encapsulating the data into HTTP packets, but what is responsible for encapsulating the HTTP packet into a TCP segment, and then an IP datagram, and then the Ethernet frame (the network interface driver?)
I posted this on Network Engineering but it was deemed off-topic. I also considered posting this on Server Fault but think this SE site is the best fit.
linux networking kernel kernel-modules internet
linux networking kernel kernel-modules internet
asked 15 hours ago
dayulolidayuloli
226110
asked 15 hours ago
dayulolidayuloli
226110
asked 15 hours ago
dayulolidayuloli
226110
asked 15 hours ago
dayulolidayuloli
226110
asked 15 hours ago
dayulolidayuloli
226110
226110
Kernel. It happens that IP cannot be built as a loadable module (and TCP cannot be disabled separately from IP). CONFIG_INET is boolean - which means y/n only, cannot be set to "m". You don't suggest that this would make any difference for what you want to know though. It doesn't actually matter that much whether you load the code in separately or not. CONFIG_IP_SCTP is a tristate, so it can be set to "m". I don't see how that makes any difference to TCP v.s. SCTP en/decapsulation.
– sourcejedi
14 hours ago
add a comment |
Kernel. It happens that IP cannot be built as a loadable module (and TCP cannot be disabled separately from IP). CONFIG_INET is boolean - which means y/n only, cannot be set to "m". You don't suggest that this would make any difference for what you want to know though. It doesn't actually matter that much whether you load the code in separately or not. CONFIG_IP_SCTP is a tristate, so it can be set to "m". I don't see how that makes any difference to TCP v.s. SCTP en/decapsulation.
– sourcejedi
14 hours ago
Kernel. It happens that IP cannot be built as a loadable module (and TCP cannot be disabled separately from IP). CONFIG_INET is boolean - which means y/n only, cannot be set to "m". You don't suggest that this would make any difference for what you want to know though. It doesn't actually matter that much whether you load the code in separately or not. CONFIG_IP_SCTP is a tristate, so it can be set to "m". I don't see how that makes any difference to TCP v.s. SCTP en/decapsulation.
– sourcejedi
14 hours ago
Kernel. It happens that IP cannot be built as a loadable module (and TCP cannot be disabled separately from IP). CONFIG_INET is boolean - which means y/n only, cannot be set to "m". You don't suggest that this would make any difference for what you want to know though. It doesn't actually matter that much whether you load the code in separately or not. CONFIG_IP_SCTP is a tristate, so it can be set to "m". I don't see how that makes any difference to TCP v.s. SCTP en/decapsulation.
– sourcejedi
14 hours ago
add a comment |
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Kernel. It happens that IP cannot be built as a loadable module (and TCP cannot be disabled separately from IP). CONFIG_INET is boolean - which means y/n only, cannot be set to "m". You don't suggest that this would make any difference for what you want to know though. It doesn't actually matter that much whether you load the code in separately or not. CONFIG_IP_SCTP is a tristate, so it can be set to "m". I don't see how that makes any difference to TCP v.s. SCTP en/decapsulation.
– sourcejedi
14 hours ago