Splynx IPv6 support

Starting from 3.0 version, Splynx has native IPv6 support. In this topic we will cover 3 main areas of IPv6 deployment:
1. IPv6 address management in Splynx;
2. Activation of IPv6 in ISP infrastructure;
3. IPv6 assignments to end-users.

If you want to know more about Mikrotik IPv6 configuration or Home router IPv6 configuration, please read following articles :

IPv6 address management
In Splynx IPv6 management is similar to IPv4 network management. Under Networking there is an IPv6 networks submenu with the ability to add network, show available networks and display detail of usage of each network.



In the selected example, we have added a /32 IPv6 network. It is the network that is usually assigned to the ISP company by the local registry.

From the /32 network we can choose /48 networks to route them on certain site or PPPoE concentrator. In total, /32 network consists of 65536 /48 networks. It means that we can have up to 65k different high-sites or PPPoE/DHCP NAS routers. Each NAS or PPPoE server or DHCP server (depends on your topology and authentication method), can connect up to 65k subscribers. Always /64 network is delegated to end user’s LAN network or his CPE. Inside one /48 IPv6 network there are 65536 /64 networks.

This basic IPv6 topology design we recommend to use inside small and medium size ISP networks. Of course, there are plenty of other IPv6 planning options that can be found on the Internet, but all these IP plans are quite complicated and just bring more complexity to IPv6 address deployment.

In our example, we have received a network 2a0f:f041::/32 from RIPE NCC.
We decided to dedicate one /48 network to Infrastructure needs – 2a0f:f041:f::/48
PPPoE concentrators will assign IPs from the ranges : 2a0f:f041:1000::/48 and 2a0f:f041:2000::/48.
In case when we have more PPPoE servers, we can use IP networks like 2a0f:f041:1100::/48 or 2a0f:f041:1011::/48 or 2a0f:f041:3050::/48. Actually we used 4-5 /48 IPv6 networks to cover all our NAS routers and infrastructure. And there are still over 65k IPv6 /48 networks left.

As was mentioned above – customers receive /64 prefixes. From these prefixes CPE/home router device creates a pool (similar to IP lan pools in IPv4 world) and IPs from this pool will be assigned to end devices.

Below is an example, how IPv6 appears in Splynx IPv6 networks when a CPE got /64 prefix delegated :


Activation of IPv6 in infrastructure
Okay, we have designed a simple IPv6 address plan, let’s recap what should be done during the first phase of IPv6 deployment :
1. BGP peering configured on IPv6 addresses
2. IPv6 network announced to BGP and BGP filters configured
3. Internal connections between infrastructure routers is established on subnetworks from

2a0f:f041:f::/48. Actually all traffic can be routed between routers using Link-local IPv6 addresses, but we have enabled IPs from range 2a0f:f041:f::/48 on our routers to check IPv6 visibility to and from outside.
4. Static routes to 2a0f:f041:1000::/48 and 2a0f:f041:2000::/48 created from BGP infrastructure to PPPoE routers.

IPv6 assignments to the end users
When all above is working, we can start with the most tricky part of IPv6 deployment – assignments of IPv6 to the end users.
Mostly everywhere, end users have own wireless router that connects their devices to the Internet.
Below is the topology of connection of advanced home user, that have one router and two access-point bridges with many devices, such as PCs and phones.

As we can see in this topology, SOHO router has one public IPv4 on it’s WAN interface and one IPv4 from LAN range that is used as a default gateway for all devices at home. It’s obvious that a router acts as a NAT server in this scenario, when all customers from home are leaving LAN network and connect to Internet from one public IP and all traffic is sent back to the network via this one single public IP address.

IPv6 world has no NAT. It means that CPE or SOHO/Home router should route public IPv6 network instead of private range. How small home office router will know what IPv6 network it should use and route? This is the job of ISP’s equipment to tell it to CPE/Home router.
In general, ISP router assignes IPv6 address to WAN interface in the same way as it did with IPv4 address, but also it should assign a “LAN” network. This is called Delegated IPv6 network and it’s the network of mask /64. Below is an example.

In our example, Home router received one single IPv6 address 2a0f:f041:a:1::1 on pppoe-client tunnel and additionally it got a prefix, that is automatically configured on LAN interface 2a0f:f041:1000:1::/64. All IPv6 end devices will receive the IP address with ND (Neighbor discover) technology that is called SLAAC. This is a technology of stateless automatic IPv6 address configuration for end users that should be used in local area networks.

In Splynx each customer has Internet service, under settings of this service there are options to assign IPv4 and IPv6 addresses.
The first option “IPv6 network” is for IPv6 assignment to the WAN interface and the second “Delegated IPv6 network” is for the network, that should be used by CPE/Home router inside LAN network.

You can also check the Mikrotik IPv6 configuration example by following this link. Should you have any questions about IPv6 support in Splynx or want to try it in action feel free to contact us.