The tagged frame has 3 bits for the priority that is also known as Class of Service (CoS), see
also IEEE 802.1Q.
CoS bits Priority Type of the data traffic
000 0 (lowest) Background
001 1 Best Effort
010 2 Excellent Effort
011 3 Critical Applications
100 4 Video, < 100 ms delay (latency and jitter)
101 5 Voice (language), < 10 ms delay (latency and jitter)
110 6 Internetwork Control
111 7 (highest) Network Control
The prioritization of the data packets is possible only if there is a queue in the components in
which they can buffer data packets with lower priority.
The device has multiple parallel queues in which the frames with different priorities can be
processed. As default, first, the frames with the highest priority are processed. This method
ensures that the frames with the highest priority are sent even if there is heavy data traffic.
Canonical Format Identifier (CFI)
The CFI is required for compatibility between Ethernet and the token Ring.
The values have the following meaning:
Value Meaning
0 The format of the MAC address is canonical. In the canonical representation of the MAC
address, the least significant bit is transferred first. Standard-setting for Ethernet switches.
1 The format of the MAC address is not canonical.
VLAN ID
In the 12-bit data field, up to 4096 VLAN IDs can be formed. The following conventions apply:
VLAN ID Meaning
0 The frame contains only priority information (priority tagged frames) and no valid
VLAN identifier.
1- 4094 Valid VLAN identifier, the frame is assigned to a VLAN and can also include priority
information.
4095 Reserved
3.4 SNMP
Introduction
With the aid of the Simple Network Management Protocol (SNMP), you monitor and control
network components from a central station, for example routers or switches. SNMP controls the
communication between the monitored devices and the monitoring station.
Technical basics
3.4 SNMP
SCALANCE S615 Web Based Management
Configuration Manual, 11/2019, C79000-G8976-C388-08 37
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