Twilio Voice SDK lets you select the specific Twilio data center used when your Call connects to Twilio. Network communication to and from Twilio will originate/terminate from the fixed, static IP address ranges listed below for each edge location. Refer to these ranges if you need to configure your local network to allow communication or apply Quality of Service routing rules to communication with Twilio.
By default, Programmable Voice SDK will use Twilio's Global Low Latency routing capability to determine which data center is closest to your user, establishing a connection through Twilio's nearest point of presence. Global Low Latency uses latency-based DNS lookups to determine the nearest data center. You may want to override this in some cases, especially when your users are working from a fixed location and using a DNS server in another edge.
For a full list of available edges, see Twilio Edges and Private Interconnect Edges
GLL requires the upstream DNS to support RFC 7871. See GLL requirements for more information
Global Low Latency uses latency-based DNS lookups to determine the nearest data center. We introduced setting an edge in Voice SDK because there can be cases where the DNS address used by the App using Programmable Voice SDK may not represent their correct edge. For example, if you are using a device in UK and the VPN server it is connected to is based in US. If we relied on latency-based DNS lookups, the edge Twilio will choose is going to be "ashburn" where "dublin" would have been preferred. Setting edge on the caller side will guarantee the least latency in this scenario.
Force connections through Twilio Ireland:
Voice.setEdge("dublin");
TwilioVoice.edge = "dublin";
Force connections through Twilio US East Coast edge over your private Interconnect connection to that edge:
Voice.setEdge("ashburn-ix");
TwilioVoice.edge = "ashburn-ix";
Let Twilio choose the nearest edge, skip setting the edge.