Call Quality Issues with BigLeaf SDWAN
Recommended Settings for BigLeaf
Note: 8x8 does not recommend anycast DNS servers. Using anycast DNS servers with 8x8 VoIP service sometimes (but not always) results in significant problems such as geo-routing issues, phone connectivity and registration issues, as well as call quality problems.
- Recommended to put VoIP phones on a separate VLAN, which enables you to give the phones 8x8's DNS and NTP servers via custom DHCP settings.
- Using 8x8's DNS servers apparently enables regional failover between 8x8's global datacenters. Using anycast DNS (Bigleaf, Google, etc.) will often, but not always cause less than optimal performance.
- The NTP servers are handed out to the phones via DHCP option 42. 8x8's DNS servers won't resolve the NTP server IPs. So this step must be done, otherwise phones will have the wrong time and can malfunction.
- BigLeaf default rules will automatically classify and prioritize 8x8 traffic, so no custom rules should be needed.
Note, it's possible to use Bigleaf's regional DNS servers' non-anycast IPs with 8x8.
Sites With Their Own DNS Servers
The ideal solution if someone has their own DNS servers is to set up conditional DNS forwarding, so all computers refer to the local DNS server. Then the local DNS server resolves 8x8 domains by using 8x8's DNS servers, and all other DNS requests go to different DNS servers.
Or, as explained above, it's possible to use Bigleaf's regional DNS servers' non-anycast IPs. For a site with its own DNS servers, such as one with an on-site Active Directory server, it can be configured with one Bigleaf non-anycast DNS server as the primary, a second as the secondary, a third as the tertiary, and so on.
Sites Without Their Own DNS Servers
This type of configuration will leave the customer without regional DNS server redundancy. The customer's firewall could hand out one of our non-anycast DNS servers' IPs to its DHCP clients. Multiple regional DNS servers cannot be added at once, because computers will consider this a round-robin configuration, where the first DNS request goes to server one, the second to server two, etc., and this would break 8x8's VoIP model. If one of our regional DNS servers goes down, then they would need to manually reconfigure the firewall to hand out a different DNS server in DHCP requests, and all DHCP clients would need to renew their leases or possible release and renew their leases.