Server hardware is advised for constructing a digital TV headend due to its designed capability for continuous operation and high quality and reliability. Key components include:
Server cases often include multiple power supplies equipped with surge protection
Memory modules incorporate error correction systems
Redundant cooling systems
These elements, among others, contribute to a robust digital TV headend setup.
CPU
The optimal CPU frequency for a digital TV headend is 2.5 - 3GHz or higher. Processors with many cores, but lower frequency (e.g. 1.8-2.5 GHz) are not well suitable for tasks requiring low latency.
Processors with L2 cache only may not be so bad, but in 99% it indicates that the rest of the equipment such as motherboard and RAM is deprecated and not suitable for use.
An example of a good processor:
Intel Xeon 10C E5-2680v2
Xeon 8C E5-2670
Intel Xeon 6C X5670
Core i5-9600K
RAM
The frequency of RAM is also quite an important thing. Approximate figures for comparison:
DDR1 400 MHz - not suitable
DDR2 600 MHz - suitable for small configurations, like receiving 10-15 channels and broadcasting them in udp
DDR3 1333-1600 MHz - suitable
DDR4 2133-2800 MHz - suitable
DDR4 2800-3400 Mhz - expensive and unnecessary
The amount of RAM is important only for storing HLS chunks (segments). The average amount of RAM for 100 hls channels is 16Gb.
Network adapters
rx/tx buffer size
NIC ring buffer sizes differ according to the NIC vendor and grade. A larger buffer size reduces the chance of packet loss during scheduling delays.
less than 1024 are generally not recommended
between 2048 and 4096 are considered good
8192 is deemed excellent
queues
Packets are transmitted between the NIC ring buffer and the operating system kernel via queues. Each queue is assigned one dedicated CPU core. Network adapters equipped with multiple queues can process packets simultaneously.
Network adapters with single queue for consumer use only and not recommended for digital TV headend setup.
Recomended network adapters
Intel
82599ES, 82599EB (2 ports)
82599EN (1 port)
i350AM2
Mellanox
MT27520
SolarFlare
SFN7122F
NOT recommended network adapters
D-Link, Realtek
Any models by for consumer use only and not suitable for digital TV headend.
Intel
Although we recommend Intel network cards, we do not recommend these models specifically. Only one queue and all data will be processed by only one CPU core.
Broadcom Corporation NetXtreme II BCM5709 - although there are multiple queues, RSS can only start working on one of them, creating a high load on a single running kernel
Broadcom Corporation NetXtreme II BCM5716 , supports allocation of interrupts to available cores, but still leaves the bulk of packets on the core 0
Others
VIA Technologies, Inc. VT6105/VT6106S Rhine-III (rev 86)
Qualcomm Atheros AR8121/AR8113/AR8114 Gigabit or Fast Ethernet
Marvell Technology Group Ltd. 88E8057 PCI-E Gigabit Ethernet Controller
Marvell Technology Group Ltd. 88E8050 PCI-E ASF Gigabit Ethernet Controller
QLogic Corp. cLOM8214 1/10GbE Controller (rev 54) - does not work changing the number of queues, by default 3 rx, 1 rx tx.
Network card NC326i
NVidia Corporation MCP55 Ethernet (rev a3) - only one queue. As a result, even with a small amount of traffic gives a very high load on the processor core, which is engaged in processing traffic from this network card, which leads to unacceptably slow packet processing.