The SoftLayer Direct Link offering was created to allow customers to establish private and secure layer 3 connectivity between their remote network environments and their computing resources on the Softlayer platform. Direct Link can be viewed as an alternative to a traditional site to site VPN solution for customers that need more consistent, higher throughput connectivity between a remote network and their SoftLayer environments. A Direct Link data flow diagram is located below to show a high level overview of the Direct Link offering. The rest of this article will cover the different ways customers can connect their remote networks to the SoftLayer backbone via direct link.
Dual IP Remote Hosts
This option requires that a customer add an additional IP or reIP their remote hosts into a 172.x.x.x IP range provided by SoftLayer from 172.16.0.0/12. SoftLayer will route the 172.x.x.x IP block provided to the customer on the SoftLayer private network to ensure connectivity can be established between the customer's remote network and their hosts on the SoftLayer platform. A diagram depicting this solution can be found below.
This option requires that a customer configure NAT on the ingress/egress point of their network. If the customer's remote network does not conflict with the SoftLayer services network (10.0.0.0/14), the IP's assigned to the customers VLAN's within SoftLayer, or the /31 assigned to the Direct Link termination port, a simple source NAT can be configured as outlined in the diagram below. If the customer's remote network does conflict with one of the SoftLayer ranges mentioned above, source and destination NAT is the recommended NAT configuration and is outlined in the diagram below.
Tunneling for BYOIP
This option allows for customers to bring their own IP space into the SoftLayer platform. It requires that a customer create a GRE or IPSEC tunnel between the remote network and their network here at SoftLayer using a SoftLayer provided gateway appliance. With this option a customer can use whatever IP space they want on the SoftLayer side and route back across the tunnel to theirremote network. The example in the diagram below shows how to get this to work and still keep connectivity to the SoftLayer services network, which means that the customer defined IP space for use on the SoftLayer platform cannot conflict with the SoftLayer services network (10.0.0.0/14), the /31 assigned to the Direct Link port, and the SoftLayer routeable 10.x.x.x IP’s assigned to the transit and customer VLANs. It is important to note that this is a configuration that is managed and supported by the customer, independent of SoftLayer. This configuration can break connectivity to the SoftLayer services network if the customer uses a 10.x.x.x block that is in use for SoftLayer services. You will not be able to assign whatever IP space you want directly on your SoftLayer hosts (BYOIP) and have it routable on the SoftLayer network inherently.