Using /126 for IPv6 router links

Tim Durack tdurack at
Mon Jan 25 19:50:35 UTC 2010

On Mon, Jan 25, 2010 at 2:23 PM, Ryan Harden <hardenrm at> wrote:
> Hash: SHA1
> Our numbering plan is this:
> 1) Autoconfigured hosts possible? /64
> 2) Autoconfigured hosts not-possible, we control both sides? /126
> 3) Autoconfigured hosts not-possible, we DON'T control both sides? /64
> 4) Loopback? /128
> Within our /48 we've carved it into (4) /50s.
> * First, Infrastructure. This makes ACLs cake.
> ** Within this /50 are smaller allocations for /126s and /128s and /64s.
> * Second, User Subnets (16k /64s available)
> ** All non-infrastructure subnets are assigned from this pool.
> * Third, Reserved.
> * Fourth, Reserved.
> We believe this plan gives us the most flexibility in the future. We
> made these choices based upon what works the best for us and our tools
> and not to conserve addresses. Using a single /64 ACL to permit/deny
> traffic to all ptp at the border was extremely attractive, etc.
> - --

This is what we have planned:

2620:0000:xx00::/41 		AS-NETx-2620-0-xx00				

	2620:0000:xx00::/44 		Infrastructure					

		2620:0000:xx01::/48		Pop1 Infrastructure			

			2620:0000:xx01:0000::/64		Router Loopback (2^64 x /128)
			2620:0000:xx01:0001::/64		Transit net (2^48 x /112)

			2620:0000:xx01:0002::/64		Server Switch management
			2620:0000:xx01:0003::/64		Access Switch management

		2620:0000:xx0f::/48		Pop16	 Infrastructure		

	2620:0000:xx10::/44		Sparse Reservation					

	2620:0000:xx20::/44		Sparse Reservation					

	2620:0000:xx30::/44		Pop1 Services					

		2620:0000:xx30::/48		Cust1 Services

			2620:0000:xx30:0001::/64		VLAN_1
			2620:0000:xx30:4094::/64		VLAN_4094

		2620:0000:xx31::/48		Cust2 Services

			2620:0000:xx31:0001::/64		VLAN_1
			2620:0000:xx31:4094::/64		VLAN_4094

		2620:0000:xx32::/48		Cust3 Services

			2620:0000:xx31:0001::/64		VLAN_1
			2620:0000:xx31:4094::/64		VLAN_4094

		2620:0000:xx32::/48		Cust4 Services

			2620:0000:xx31:0001::/64		VLAN_1

			2620:0000:xx31:4094::/64		VLAN_4094

		2620:0000:xx32::/48	RES-PD-32	(4096 x /60)
		2620:0000:xx3f::/48	RES-PD-3f	(4096 x /60)

	2620:0000:xx40::/44		Pop2 Services					

	2620:0000:xx50::/44		Pop3 Services					

	2620:0000:xx60::/44		Pop4 services					

	2620:0000:xx70::/44		Pop5 Services					

This is a multiple campus network, customers are all internal. I have
had to squeeze Residential PDs down to /60s to make it fit. One Pop is
really 3 sites in one. This has had to be massaged into one Pop also.
To be safe, I'm thinking of adjusting loopbacks and ptp to be /64s.

I'm reasonably happy with the plan, but it doesn't seem to have that
much room to grow.

Sent from Brooklyn, NY, United States

More information about the NANOG mailing list