Mitel MiVOICE BUSINESS, Engineering Manualline

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Engineering Guidelines
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The sequence above assumes that the phones get information from a DHCP server. The
information can also be manually entered into a phone as it starts to boot up, to make sure the
information is fixed and requires little DHCP intervention. This method is particularly useful if
a phone is used on a remote WAN link and the router cannot forward DHCP requests, or if a
local DHCP server does not exist. It is also useful on VPNs, for the same reasons.
LLDP-MED AND IP PHONE NETWORK POLICY
Link Layer Discovery Protocol - Media Endpoint Discovery (LLDP-MED) is based on
VoIP-specific extensions to the IEEE 802.1AB LLDP standard. LLDP is the IEEE neighbor
discovery protocol and allows information to be gathered from network devices such as switches
and wireless access points. The information gathered with LLDP, aids in troubleshooting and
provides data to management systems so that management systems can create accurate views
of the network’s topology.
LLDP-MED allows for information sharing between VoIP endpoints such as IP phones and
network devices such as L2 Ethernet switches.
LLDP-MED can be used to simplify the deployment of IP phones with auto-discovery. This
means that IP phones can auto-discover network policy from an LLDP-MED compliant L2 switch
to obtain the following network policy information:
• VLAN (802.1.Q) information
• COS L2 Priority (802.1p) information
• DSCP (L3 Priority) information.
Notes Regarding LLDP-MED
Network loading
Traffic from LLDP-MED packets will not cause network loading problems since LLDP-MED
packets are not forwarded by L2 switches. The packets are sent from the phone to the L2 switch
and vice versa and since these packets are not forwarded by L2 switches, the packets remain
only on this LAN segment.
Simplifying IP Phone deployment
LLDP-MED can be used in conjunction with DHCP options to provide the phone with network
policy information. Using LLDP-MED can remove the requirement to program the DHCP server
with VLAN, L2 COS priority, and DSCP priority information. LLDP-MED can also remove the
need to enable DHCP forwarding in the general routing infrastructure.
LLDP-MED and using scopes
In many situations, especially where part of the network uses different LAN policy from other
parts, use of LLDP-MED may simplify network configuration. The appropriate LAN policy values
can be applied directly to the L2 switching gear in each section of the LAN separately, rather
Note: Some DHCP interaction is still required to provide IP Phones with the IP address
of the ICP and TFTP server. In cases where DHCP servers are being used, DHCP
forwarding (IP Helper) will still need to be enabled on routers, however, with LLDP-MED
used to provide LAN policy (VLAN in particular) this will only be needed in the voice
VLAN.