Engineering Guidelines
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tagged, but traffic from the data VLAN must be sent untagged for the devices that are not able
to handle VLAN information.
The requirement to use VLAN and priority queuing becomes obvious when both data and voice
information must share a link between units within the network. It is important that the
deterministic voice information gets priority over the non-deterministic data traffic. This is where
IEEE 802.1p comes into play (IEEE 802.1p is a subset of IEEE 802.1Q).
Routers or Layer 3 switches involved in segmenting the network also need connections to the
different VLANs. Each VLAN is identified by a VLAN number and by a unique subnet address.
Routers and Layer 3 switches that are unaware of VLAN can still pass data between the VLANs.
A separate physical connection to each VLAN must exist and ports on the Layer 2 switch must
pass information only to and from one specific VLAN. At the Layer 2 port, the VLAN information
is removed on egress and added on ingress according to the port or VLAN configurations.
Some routers are VLAN-aware and are considered to include a virtual Layer 2 switch within
the unit, which then directs data according to the VLAN information. These devices are often
referred to as including virtual ports. Their advantage is that only one physical connection is
required to handle multiple VLANs.
In a Cisco based environment the recommended settings are:
•
Voice Packets: DSCP: 46, 802.1p:5
•
Signalling Packets: DSCP: 26, 802.1p:3
•
Other Packets: DSCP:0 802.1p:0
For Cisco based environments refer to “Network QoS settings in a Cisco Environment” on
page 252.
LAN QOS POLICIES
The 3300 can apply different LAN QoS policies to voice packets, signalling packets and other
packets. The LAN Policy (QoS) form in ESM is used for setting the LAN QoS policy values.
Refer to “LAN policy values for media, signalling and other” on page 238.
TOS-TO-COS (IEEE 802.1P) MAPPING AND SOFTPHONES
In a converged environment with voice and data traffic on the network, some form of priority
mechanism should be used. If a voice device is resident on a data device, it may not be possible
to separate the traffic to independent network interfaces. In this case it is likely that both voice
and data appear from the same IP address and within the same subnet. This is the situation
for a softphone running on a PC.
Often the PC does not support VLAN, although it may support priority. Be careful with this
setting, since the VLAN tagging is added and the VLAN 0 is used. Different vendors treat VLAN
0 in different ways. If operation cannot be determined it is better to treat the PC as non-VLAN
aware and let the Layer 2 switch tag this with the Default or Native VLAN settings. For
non-VLAN-aware PCs, the only form of priority identification is from within the voice application.
The Type-of-Service field is set by this application on the PC. To get the correct VLAN priority,
configure the access port in the network to map this Type-of-Service (TOS) information, either
precedence or DSCP, to a VLAN priority (COS). Voice is still on the same subnet (and
Содержание MiVOICE BUSINESS
Страница 1: ...Mitel MiVoice Business RELEASE 7 2 ENGINEERING GUIDELINES ...
Страница 15: ...Chapter 1 ABOUT THIS DOCUMENT ...
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Страница 22: ...Engineering Guidelines 8 ...
Страница 23: ...Chapter 2 SYSTEM OVERVIEW ...
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Страница 28: ...Engineering Guidelines 14 ...
Страница 29: ...Chapter 3 TYPICAL CONFIGURATIONS ...
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Страница 73: ...Chapter 4 PHONES AND VOICE APPLICATIONS ...
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Страница 95: ...Phones and Voice Applications 81 Figure 9 ICP Connection Paths and Limitations ...
Страница 100: ...Engineering Guidelines 86 ...
Страница 101: ...Chapter 5 POWER ...
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Страница 129: ...Chapter 6 PERFORMANCE ...
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Страница 135: ...Chapter 7 APPLICATIONS ...
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Страница 142: ...Engineering Guidelines 128 ...
Страница 143: ...Chapter 8 EMERGENCY SERVICES ...
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Страница 151: ...Chapter 9 IP NETWORKING ...
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Страница 167: ...Chapter 10 LICENSING ...
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Страница 183: ...Chapter 11 BANDWIDTH CODECS AND COMPRESSION ...
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Страница 209: ...Chapter 12 NETWORK CONFIGURATION CONCEPTS ...
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Страница 245: ...Chapter 13 NETWORK CONFIGURATION SPECIFICS ...
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Страница 309: ...Appendix A CAT 3 WIRING ...
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Страница 315: ...CAT 3 Wiring 301 Figure 55 CX MX MXe AX and LX Minimum Cable Standard ...
Страница 316: ...Engineering Guidelines 302 ...
Страница 317: ...Appendix B INSTALLATION EXAMPLES ...
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Страница 335: ...Appendix C LLDP AND LLDP MED CONFIGURATION EXAMPLES ...
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Страница 347: ...Appendix D VOIP AND VLANS ...
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Страница 353: ...Appendix E VOIP SECURITY ...
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