5 ms·

Why?

by api 2y ago

Why?

Joel_Mckay 2y ago
In general, the IPv6 stack is not supported on many smaller mcu. It is not that options like FreeRTOS can't support the stack, but rather the resource constraints pose a challenge. That being said, most modern SoCs are competitively priced... and will boot Linux just fine for under $5/part. =3
- elcritch 2y ago
  Some of the new IoT protocols build on ipv6 natively. The resource overhead is minimal for modern mcus. Dropping dhcp and arp can save a lot of resources too. Also I have mcus with more ram than my first pc.
  - jeroenhd 2y ago
    Disabling IPv6 in ESP-IDF can save about 40KiB of flash and 2KiB of RAM. Not enough that I'd do it by default, but I've hit the limit of some of my hobbyist ESP32s to the point where I've disabled modules to cram my code in there. Disabling IPv4 saves 25KiB of flash and less than a KiB of RAM. If you're down to the last kilobytes, disabling IPv6 makes more sense than disabling IPv4. Both options are choices of last resort, though.
    - Joel_Mckay 2y ago
      A dual core 240MHz cpu with hardware paged flash and spi ram expansion support is not "small" in my opinion. However, I am a fan of their price point for hobby projects. Best regards =3
LegionMammal978 2y ago
Eliminating NAT makes virtual networking much hairier. E.g., my desktop is currently connected to a big enterprise network that keeps track of all devices and will only allocate one IP address per MAC address. That leaves no IPs for any VMs on my desktop to use, so they must go through NAT if they want to communicate with the outside world.
- pcpuser 2y ago
  That's definitely a limitation of your network. I don't see how ipv6 can shoulder any responsibility here.
- Dylan16807 2y ago
  Are you talking about eliminating NAT on IPv4? IPv6, set up the normal way, does not allocate IPs. Devices can and will have several at once and their VMs can easily get some too.
  - wmf 2y ago
    The enterprise corrupted IPv6 and disabled SLAAC so devices have to use whatever DHCPv6 gives them.
    - somanyphotons 2y ago
      How does that work for android devices? I heard they don't allow dhcp provided addresses?
      - wmf 2y ago
        The Android problem only occurs in an IPv6-only enterprise network which is very rare. Otherwise Android can use IPv4.
- pjc50 2y ago
  Shouldn't the VMs have their own MACs?
  - jeroenhd 2y ago
    If they're not routed directly through the network card but use a virtual switch instead, the network upstream only sees the server MAC. If they're directly hooked into the network card they can have their own MACs, but that approach can make it hard to communicate between host and VM.
deleted 2y ago
[deleted]
positr0n 2y ago
Great question that I don't think the other commentors really answered. Sadly I don't really know "why" either. Second system effect? Instead of making IPv6 just "IPv4 with 128bit instead of 32bit address space" the designers changed a bunch of things. NDP is new and different than ARP. ICMPv6 is extended and different. MLD instead of IGMP for multicast group membership. DHCP is extended and has a bunch of other alternatives, like SLAAC. IPsec is mandatory now. All the new IPv6 protocols seem more secure, more powerful, and more efficient. So I guess that is "why". But I bet in an alternative history where backwards compatibility and the upgrade process were prioritized IPv6 would be a lot more widespread.

Why?

by api 2y ago

Why?

In general, the IPv6 stack is not supported on many smaller mcu. It is not that options like FreeRTOS can't support the stack, but rather the resource constraints pose a challenge. That being said, most modern SoCs are competitively priced... and will boot Linux just fine for under $5/part. =3

elcritch 2y ago
Some of the new IoT protocols build on ipv6 natively. The resource overhead is minimal for modern mcus. Dropping dhcp and arp can save a lot of resources too. Also I have mcus with more ram than my first pc.
- jeroenhd 2y ago
  Disabling IPv6 in ESP-IDF can save about 40KiB of flash and 2KiB of RAM. Not enough that I'd do it by default, but I've hit the limit of some of my hobbyist ESP32s to the point where I've disabled modules to cram my code in there. Disabling IPv4 saves 25KiB of flash and less than a KiB of RAM. If you're down to the last kilobytes, disabling IPv6 makes more sense than disabling IPv4. Both options are choices of last resort, though.
  - Joel_Mckay 2y ago
    A dual core 240MHz cpu with hardware paged flash and spi ram expansion support is not "small" in my opinion. However, I am a fan of their price point for hobby projects. Best regards =3

LegionMammal978 2y ago

Eliminating NAT makes virtual networking much hairier. E.g., my desktop is currently connected to a big enterprise network that keeps track of all devices and will only allocate one IP address per MAC address. That leaves no IPs for any VMs on my desktop to use, so they must go through NAT if they want to communicate with the outside world.

pcpuser 2y ago
That's definitely a limitation of your network. I don't see how ipv6 can shoulder any responsibility here.
Dylan16807 2y ago
Are you talking about eliminating NAT on IPv4? IPv6, set up the normal way, does not allocate IPs. Devices can and will have several at once and their VMs can easily get some too.
- wmf 2y ago
  The enterprise corrupted IPv6 and disabled SLAAC so devices have to use whatever DHCPv6 gives them.
  - somanyphotons 2y ago
    How does that work for android devices? I heard they don't allow dhcp provided addresses?
    - wmf 2y ago
      The Android problem only occurs in an IPv6-only enterprise network which is very rare. Otherwise Android can use IPv4.
pjc50 2y ago
Shouldn't the VMs have their own MACs?
- jeroenhd 2y ago
  If they're not routed directly through the network card but use a virtual switch instead, the network upstream only sees the server MAC. If they're directly hooked into the network card they can have their own MACs, but that approach can make it hard to communicate between host and VM.

deleted 2y ago

[deleted]

positr0n 2y ago

Great question that I don't think the other commentors really answered. Sadly I don't really know "why" either. Second system effect? Instead of making IPv6 just "IPv4 with 128bit instead of 32bit address space" the designers changed a bunch of things. NDP is new and different than ARP. ICMPv6 is extended and different. MLD instead of IGMP for multicast group membership. DHCP is extended and has a bunch of other alternatives, like SLAAC. IPsec is mandatory now. All the new IPv6 protocols seem more secure, more powerful, and more efficient. So I guess that is "why". But I bet in an alternative history where backwards compatibility and the upgrade process were prioritized IPv6 would be a lot more widespread.