Hardware Requirements - Bosch DICENTIS Installation Manual

18 en | System installation design and planning
4.2

Hardware requirements

Switches
The following minimum requirements and recommendations apply to switches used in a
DICENTIS:
Requirement
Gbit Ethernet
Packet forwarding in
HW per port
>1.2Mpps
Quality of Service
With strict priority
Warning: IEEE802.1p is also used for QoS, but is limited to layer 2. Since OMNEO uses IP
communication, this mechanism is not suitable, so make sure the used equipment uses
DiffServ QoS!
The table below gives an overview of the used DSCP values which need to be configured in
the switch:
Data
PTP sync,
delay req
PTP follow-
up, delay
response,
audio
(reserved)
Control
Warning: Please check thoroughly if your switch's highest priority queue is label as #1 or e.g.
#8, because this may differ per brand. Unfortunately this is not consistent over the different
brands. Setting it wrong is worse than not having priority.
2023-02 (draft) | 4.3-draft |
Standard Settings
IEEE802.3 Switch latency is maximally 10µSec with Gbit.
Valid for both copper and/or fiber ports.
n.a. If SW is responsible for packet switching, this would
result in variable latency which is unacceptable.
DiffServ To make sure PTP synchronization packets and
audio packets get priority over control packets.
OMNEO uses QoS on IP level to avoid
synchronization and audio problems on busy
networks. Although the system does work without
problems on relatively quiet networks (< 10%
network load) it is important to configure your
network switches correctly.
The used QoS is Differentiated Services or DiffServ,
which is part of the Type of Services field (ToS) in
the IP header. For more details on
header, see Wikipedia.
DSCP dec DSCP hex
56 0x38
46 0x2E
8 0x08
0 0x00
Installation manual
DSCP Label TOS byte
(hex)
CS7 0xE0
EF 0xB8
CS1 0x20
Best effort 0x00
Bosch Security Systems B.V.
DICENTIS
DiffServ & IP
Switch
Priority
queue
Highest
High
Low
None