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DHCP on trunk port

I have installed two Catalyst 4507R connected on trunk and I have configured an a Vlan 3 for IP telephony and an a Vlan 2 for dates.

The interface ports at begin were configured all:

switchport access vlan 2

switchport voice vlan 3

qos trust device cisco-phone

qos trust cos

service-policy output autoqos-voip-policy

auto qos voip cisco-phone

tx-queue 3

priority high

shape percent 33

The ip addresses for Vlan 3 (voice) are released from DHCP which is configured on the Catalyst.

The ip addresses for Vlan 2 are released from Windows 2000 DHCP server connected on a port of Catalyst.

With configuration above we seen that IP Telephony

got ip address from Windows 2000 DHCP server.

All it function if I connect DHCP Server on port configured like below:

switchport access vlan 2

switchport mode access

Somebody can explain it ?

Thanks

Lorenzo

  • Other Network Infrastructure Subjects
1 REPLY
Silver

Re: DHCP on trunk port

Th command switchport mode access is needed since the default Administrative Mode for a L2 port is dynamic desirable, which attempt negotiating to be a trunk when initialized.

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