Mitel MiVoice Business Troubleshooting Manual page 71

PHONE SYMPTOM
53xx IP Sets Phones stuck at DHCP
discovery after upgrade to
MCD 5.0 SP1.
Table 15: Specific Model Troubleshooting
PROBABLE CAUSE
Misconfiguration issue
between Layer 2 switch port
and DHCP server.
Prior to MCD 5.0 SP1, the
53xx IP Phones would accept
both untagged and tagged
frames even though they
send tagged frames with
VLAN ID of N (where N is a
value from 1 to 4096.)
In MCD 5.0 SP1, the
firmware for 53xx IP Phones
changed to adhere to the
industry-standard behavior
for VLAN aware devices as
follows: when the DHCP
server offers option 125 with
VLAN ID of N, the IP Phone
releases its current IP
address and sends VLAN
N-tagged DHCP discovery.
The DHCP server responds
with a DHCP offer tagged
with VLAN N. In a typical
VLAN aware device, all
outgoing/incoming frames
are expected to be tagged.
Hardware
CORRECTIVE ACTION
Reconfigure network on the basis of
the following rule of thumb: If VLAN
ID and Priority are assigned to
DHCP option 125, L2 port is
expected to send and receive
Tagged frame with VLAN ID ( In
Cisco term, L2 port is configured as
a Trunk port).
Examples and solutions to some of
the network misconfiguration:
Case 1
================
L2 port setting (to which 53xx is
connected):
Access port ( untagged) for VLAN ID
of N.
IP phone obtains VLAN ID via:
DHCP option 125 is configured with
VLAN ID of N, and priority of N.
Solution:
• Remove the VLAN ID from DHCP
option 125.
or
• Make the L2 port and access port
tagged for VLAN N.
Case 2
================
L2 port setting (to which 53xx is
connected):
Access port (untagged) for VLAN ID
of N.
IP phone obtains VLAN ID via:
From the LAN policy of LLDP/CDP.
Solution:
Make the L2 port a trunk port tagged
for VLAN N.
Case 3
================
L2 port setting (to which 53xx is
connected):
Access port (untagged) for native
VLAN.
IP phone obtains VLAN ID via:
DHCP option 125 is configured with
native VLAN ID of 1 and priority.
Solution:
Remove VLAN 1 and priority from
DHCP option 125.
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