Mitel 5560 IPT none Specifications download pdf (Page 250)

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.

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.

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Mitel 5560 IPT none Specifications Page 250