ECDN has three runtime components:
- ECDN servers - VMs that run in your intranet. It is shipped as a virtual appliance. See specifications below.
- ECDN Management Portal - runs in the cloud and accessed via a browser.
- ECDN Backend services - set of api services that run in the cloud to support the ECDN service.
System requirements for ECDN server VM instances
Software for ECDN server is shipped as a virtual appliance image file, one for each supported hypervisor. During installation, you will use these image files to create ECDN server VM instances.
ECDN virtual appliance uses:
| Operating system | Ubuntu Linux 16.04 LTS (modified) |
The minimum requirements for ECDN server VMs are:
| CPU | 1 vCPU (2 vCPUs recommended) |
| Memory | 4GB RAM |
| Storage | 4GB of disk space |
| Optionally - you may attach a second hard disk to enable persistence of VOD cache content to disk. When this second hard disk is not attached, both live and VOD streams are cached in memory (and are lost when VMs are rebooted). The size of this second disk can be any. We suggest, the optimal size to at least be 20% of the size of your VOD library. |
Supported hypervisors are:
| VMware ESXi | version 6.5 | virtual appliance shipped as a .OVA file |
| Microsoft HyperV | version R2 2012 | virtual appliance shipped as a .VHDX file |
The host hardware can have:
| Network interface | 1Gbps or 10Gbps NICs |
ECDN server VMs may be deployed in a shared or dedicated host server.
Notes:
- With video streaming, the network capacity is usually the most constraining factor.
- Inbound WAN bandwidth limits the number of video streams that can be watched at the same time.
- Outbound LAN bandwidth limits the number of viewers that can be served by one ECDN server.
- You may deploy more than one ECDN server VM on the same host hardware to the extent that the underlying host NIC is not over-subscribed.
Number of viewers supported by one ECDN server instance
The number of viewers that can be supported by one ECDN server instance depends on:
- The bitrate of the incoming video stream, and ...
- The capacity of the NIC in the host hardware.
Consider the following example. Assume you have a:
- You want to support one 1080p (3Mbps bitrate) video stream, and ...
- ... the host hypervisor has 1Gbps NIC.
- Network flow overhead = 20%
The bandwidth calculations would be:
- Inbound WAN bandwidth: 3Mbps
- Outbound LAN bandwidth: 3Mbps / viewer
| Number of viewers | = | (Total NIC capacity * 0.8) – Inbound bandwidth | = | 800Mbps – 3Mbps | = | 265 |
| Outbound LAN bandwidth | 3Mbps |
If the hypervisor has a 10Gbps NIC, the number of supported viewers scales up to 2,665.
Notes:
- Required inbound bandwidth increases when for the same video, there are multiple bitrates streams that are sent to the server.
- Required inbound bandwidth also increases when there are multiple broadcast streams being watched at the same time from a given location.
- Lower bitrate streams reduces the per-viewer bandwidth requirement, and more viewers will be able to connect to the same ECDN server.