prefix delegation size with SB8200?

Question

I recently gave up my static IP addresses and figured I'd switch out my comcast provided modem with one I own. I purchased an Arris SB8200. Once provisioned, my CPE requested a prefix delegation (configuration unchanged). I received the same v4 address but only a single /64 for v6, which is insufficient since I run more than one VLAN. Comcast was unable to provide me any assistance as they said they can't see any configuration in that modem. The web interface provides no tunable options and very limited visibility into anything but the log and the HFC channels. Docs for the Arris aren't terribly helpful.

Long story short, I switched it back to the comcast gear and will be receiving a new device from comcast to address my v6 issue. My question is this:

Are there any folks out there running a business connection on a SB8200 and getting more than a /64 of v6 space? If so, how?

Thanks

ndb217 · Accepted Answer

Yes. I spoke with Arris support and this is the transcript detailing the capabilities.

TL;DR: according to Arris:

It is not configurable. Arris support, like so many others, don't really understand v6 and seem to by mostly guessing about the answers.

I find this odd based on my experience with dhcpv6-pd relay, but since I can't see anything inside the modem or HFC network, I have no idea and am just guessing at this point.

Transcript:

( 1m 56s ) Arris Support: Thank you, how may I help you?
( 2m 44s ) ndb217: I have a question about the configuration settings. When I provision this on Comcast I should receive a /56 of IPv6 address space as a prefix delegation. This modem only hands me a /64. Is there a way to change that?
( 3m 5s ) ndb217: Comcast states that it is a modem setting and that they cannot change it
( 3m 48s ) Arris Support: No ndb217. In modem's web manager page, we are unable to modify any setting because it is a cable modem not the gateway or the router.
( 4m 11s ) ndb217: Right, but this devices handles the prefix delegation
( 4m 32s ) ndb217: So the prefix delegation size for IPv6 is hard coded into the modem as a /64?
( 5m 48s ) Arris Support: Yes. Most of the router/ gateway doesn't support IPv6 and we can change the IPv4 address but not IPv6.
( 7m 3s ) ndb217: Well, most hardware does IPv6 by default now, and nearly all of the content is available via IPv6.You really should fix this as it is problematic for anyone that needs IPv6.
( 7m 14s ) ndb217: I will be returning this device
( 8m 3s ) Arris Support: I understand. If your router supports IPv6 then you can manually assign the IPv6 address because router is having option to d do that but in modem, we can't change any setting.
( 8m 28s ) ndb217: Thanks

CC_Michelle · Answer

Thanks so much for taking the time to reach out to us through our business forums. I am truly sorry for the delay in our response and truly appreciate your patience. I am sorry to hear that your purchased modem did not meet your expectations. Have you attempted to reach out to Arris directly to see if they can provide any more insight into the modem and its functions?

CC_Anisa · Answer

Thank you for providing this information and I understand how frustrating this can be and you have reached an amazing team to help look into this for you. Can you please send us a private message with your name, the full address, and the phone or account number?

ndb217

prefix delegation size with SB8200?

ndb217

CC_Michelle

CC_Anisa