Assigned a /56 static, told I can only use 1/256th of it.

That does not sound right to me. Im still experimenting with my setup, so I have not tried anything larger than a /64. What is your modem model, and how are you requesting your prefixes from the modem? There are known issues with the WIDE DHCPv6 client and prefix != /64

Yeah, I've got a Cisco as well. It will give a SLAAC, but I need to actually use at least 10 /64's, and ideally more.

I'm trying to use static, so I shouldn't be requesting prefixes. 

However, when I did request them, I was trying to get the /56 I've been assigned.  

You can use static from a PD, that's what I had been doing with my netgear. I was unable to utilize more than the /60 I was delegated, but I had a segment that was not SLAAC enabled and I was statically assigning the host addresses. When i used addresses outside of that /60 I saw administratively denied errors, but admittely that was like 9 months ago. Also, no matter what you request, you'll get whatever the DHCP service is configured to hand you. I was originally requesting a /64 and receiving a /60. I never really understood the purpose of the hint. 

I have an understanding that you are assigned a /56 and feel like you need to have the entire address space available to you for use.  I have static IPv4 and was assigned a static /56 IPv6 as well.   On my Netgear FVS318Gv2 firewall, I received a /64 delegation from which I allocated a DHCPv6 pool and a set of static addresses.

So, my question to you is this.  What makes you think you need more than (in my case anyway) the /64 worth of IPv6 addresses wich turns out to be 18,446,744,073,709,551,616 (in words that is eighteen quintillion, four hundred forty-six quadrillion, seven hundred forty-four trillion, seventy-three billion, seven hundred nine million, five hundred fifty one thousand, six hundred and 16) for your network?  A single /64 is the ENTIRE  32 bit IPv4 address space squared!

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@gguldens56 wrote:

I have an understanding that you are assigned a /56 and feel like you need to have the entire address space available to you for use.  I have static IPv4 and was assigned a static /56 IPv6 as well.   On my Netgear FVS318Gv2 firewall, I received a /64 delegation from which I allocated a DHCPv6 pool and a set of static addresses.

 

So, my question to you is this.  What makes you think you need more than (in my case anyway) the /64 worth of IPv6 addresses wich turns out to be 18,446,744,073,709,551,616 (in words that is eighteen quintillion, four hundred forty-six quadrillion, seven hundred forty-four trillion, seventy-three billion, seven hundred nine million, five hundred fifty one thousand, six hundred and 16) for your network?  A single /64 is the ENTIRE  32 bit IPv4 address space squared!

What make me think that? Well, the RFCs from the people that designed IPv6 make me think that.

RFC 5375 explains that a /64 is the subnet size per broadcast domain, or VLAN. I have 10 VLANs at my main site, plus over 30 VPN tunnels to remote sites. That means I need at least 40 /64 subnets.

RFC 6177 says I should be getting a /48 as a business cusomter. As you point out, that is a lot of subnets, so I can be OK with a /56, even though that isn't following the standard. HOME users are to be assigned a /56, but Comcast normally does a /60.
Again, those are reasonable for most people, so I can live with that, even though, I shouldn't have to.

RFC 7421 explains why the /64 subnet bountry was chosen.

If you think you know better than the people that wrote these RFCs, go write your own RFC and explain why they're not as smart as you. Maybe you'll change their mind.

Until that point, I'll take the IPs I'm pay for and I'm entitited to, thank you very much. 

Couldn't agree more with you.

I went round and round with Comcast trying to statically assign subnets from my /56 delegation.  What I learned was that they do not yet have a cable modem that will allow static (e.g. manual) assignments.

Right now it appears that we have to accept the dynamic allocation of subnets from the /56 delegation from the cable modem.  I am using a Barracude F-Series and I have two internal networks that each need their own subnet.  I wanted to pick the subnets and statically assign them because I didn't want them to change.

But for now it appears that we have to let the cable modem pick which subnets are assigned to internal interfaces as there is no provision in the cable modem to set up static routes.  

If you have a router that will handle the prefix delegation and you have multiple internal interfaces, it should pick up separate subnets for each from the cable modem.  This now works for us.  But we still want the cable modem to allow us to define which numbers we want so there is no chance it will get changed on us.

Hope this helps.

Kevin