4 ms·

I don't know if this qualifies as legitimate, but Comcast has already decided to allocate /128 to customers with "directly connected CPE", which sounds like peo

by guan 15y ago

I don't know if this qualifies as legitimate, but Comcast has already decided to allocate /128 to customers with "directly connected CPE", which sounds like people who have just a cable modem and didn't pay for a "home gateway device". NAT could be useful if you plug that cable modem into a Linux box. http://blog.comcast.com/2011/11/ipv6-deployment-technology.html http://blog.comcast.com/2011/11/ipv6-deployment-technology.h...

wmf 15y ago
You're interpreting it wrong; Comcast is going to provide at least /64 to each customer but they just haven't turned on prefix delegation yet.
- agwa 15y ago
  /64 is almost as bad and will lead to IPv6 NATing. What if you want multiple subnets (for example, a separate guest network, which some high-end consumer access points already tout as a selling point)? You don't want to sub-divide your /64 because then stateless auto configuration won't work. You could bridge multiple subnets with the same /64 prefix and use a layer 2 firewall (ebtables in Linux), but that's ugly. NAT is the only other option. That said, Comcast did leave open the possibility for shorter prefixes, possibly as early as 2012, and they have already received quite a thrashing on their IPv6 beta tester forums for using /64 prefixes. So they might eventually do the right thing. I'm optimistic :-).
pasbesoin 15y ago
My opinion is that when you're dependent upon a (possibly recalcitrant) upstream provider, it's best to have means of dealing with whatever they give you. If in some circumstance someone hands you only one address (or, one address too few, perhaps), you can still hang your own network behind it.
syncsynchalt 15y ago
I think you're reading that wrong. The CPE (the cable modem itself) gets a /128, similar to the 10.0.0.0/8 address that it currently gets (that is not visible to the end user). They then go on to say that the home gateway gets a /64.
- wmf 15y ago
  No, in this case CPE means whatever is attached to the cable modem.

by guan 15y ago

wmf 15y ago

You're interpreting it wrong; Comcast is going to provide at least /64 to each customer but they just haven't turned on prefix delegation yet.

agwa 15y ago
/64 is almost as bad and will lead to IPv6 NATing. What if you want multiple subnets (for example, a separate guest network, which some high-end consumer access points already tout as a selling point)? You don't want to sub-divide your /64 because then stateless auto configuration won't work. You could bridge multiple subnets with the same /64 prefix and use a layer 2 firewall (ebtables in Linux), but that's ugly. NAT is the only other option. That said, Comcast did leave open the possibility for shorter prefixes, possibly as early as 2012, and they have already received quite a thrashing on their IPv6 beta tester forums for using /64 prefixes. So they might eventually do the right thing. I'm optimistic :-).

pasbesoin 15y ago

My opinion is that when you're dependent upon a (possibly recalcitrant) upstream provider, it's best to have means of dealing with whatever they give you. If in some circumstance someone hands you only one address (or, one address too few, perhaps), you can still hang your own network behind it.

syncsynchalt 15y ago

I think you're reading that wrong. The CPE (the cable modem itself) gets a /128, similar to the 10.0.0.0/8 address that it currently gets (that is not visible to the end user). They then go on to say that the home gateway gets a /64.

wmf 15y ago
No, in this case CPE means whatever is attached to the cable modem.