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AEQ Audio Over IP
Routing System
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APPENDIX 7: DANTE based AEQ AoIP Ethernet Switches.
A7.1. General configuration of DANTE based AEQ AoIP Ethernet Switches.
The vast majority of AEQ AoIP systems will require a network switch.
This document will provide information which will help the decision of which switch to purchase
and provides data for its correct configuration.
Requirements:
•
Switches must be Gigabit rated (1000 Mbps). In the case of NETBOX 4 MH and
PHOENIX VENUS V3, 100 Mbps switches can also be used.
•
Quality of Service (QoS) with four queues.
•
Diffserv (DSCP) QoS with strict priority.
•
A managed switch is required to allow custom configuration as well as detailed
operation information.
•
Switches prioritise packets using DSCP/Diffserv Values. The packet priority values used
for Dante have been chosen to make it simple to configure QoS with a wide range of
switches. Some switches require additional configuration to recognise and prioritise
specific DSCP values. The table below shows the various Diffserv Code Points (DSCP)
packet priority values:
Priority Usage DSCP Label Hex Decimal Binary
High Time critical PTP events CS7 0x38 56 111000
Medium Audio PTP EF 0x2E 46 101110
Low (reserved) CS1 0x08 8 001 000
None Other traffic BestEffort 0x00 0 000000
Whilst most switches support DSCP they may default to either not using it, or having the
priorities incorrectly mapped for AEQ AoIP / Dante. For this reason, managed switches must be
used in an AEQ AoIP system. Managed switches allow the user to interrogate and, if necessary,
change the settings of the switch, usually via a web interface. Some switches came with EF
(Audio) prioritised over CS7 (Clocking). If Audio packets are prioritised above PTP (sample
clock timing) packets, it can lead to higher clock jitter and longer lock times. In extreme
situations (high audio traffic), it could lead to a network node loosing sync and dropping audio
packets because the sample timing has become skewed.
Please refer to the user documentation of your specific switch for more information regarding
configuring QoS.
Whilst not an exhaustive list, the following switches were found to be suitable generally for AEQ
AoIP after the aforementioned setup was carried out:
•
Cisco SG300
•
Cisco SG200
•
Netgear GS724T
NETBOX 4 MH admits PoE or PoE+ power supply. This option advises the use of switches that
provide that type of power supply. Some switches of Cisco SG300 and SG350 family are
suitable, with different capacity regarding Ethernet ports and PoE+ power:
•
Cisco SG300 - 10 PP-K9 with 62 W PoE for 8 ports (2 of them for NETBOX 4 MH).
•
Cisco SG350 - 10 MP-K9 with 128 W PoE for 8 ports (5 of them for NETBOX 4 MH).
•
Cisco SG300 - 52 MP-K9 with 740 W PoE for 48 ports (30 of them for NETBOX 4 MH).
When a NETBOX 4 MH is added to a system with a switch previously selected that is not a PoE
or PoE+ one and there is no socket where the NETBOX 4 MH should be installed, a PoE+
injector can be installed between a switch port and the unit. For this purpose, the following
switch is approved:
•
Linksys Profesional LACPI30 - PoE Injector.