Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Catalyst 4500 and Avaya phones

Hi guys . We have a ESR 4500 connected to Catalyst 4500.  Dhcp server is running on Catalyst and when I connect Avaya 9608 phone  to ERS I can't get IP from DHCP server , only waiting LLDP message ,also I connected 9608 to the port of Catalyst (sw mode access,sw acc  vlan 650)and got same issue -no dhcp ->waiting LLDP ... that mean  something wrong on the config Catalyst ?? Avaya 9608 can not get dhcp option from core catalyst switch ...

   Can you help me with please ?

9608 works only with static IP , dhcp  ip still doesn't work ,  no lldp configured , here are configs :

#conf of the dhcp pools, catalyst4500

ip dhcp excluded-address

ip dhcp pool Voice_VLAN_650



  option 66 ip

option 242 ascii "MCIPADD=,MCPORT=1719,HTTPSRVR=,L2Q=1,L2QVLAN=650,VLANTEST=20"

option 250 ascii "MCIPADD=,MCPORT=1719,TLSSRVR=,HTTPSRVR=,DIR=sip,TLSDIR=sip,HTTPDIR=sip"

#conf of the port Catalyst where ERS4500 is connected

interface GigabitEthernet2/45

description Avaya_Switch

switchport access vlan 650

switchport mode access

#ERS4500 vlan conf , port 49 is untagallconnected to catalyst4500

vlan create 650 type port 1

vlan name 650 "Voice_VLAN"

vlan ports 1-48 tagging unTagPvidOnly

vlan ports 50 tagging tagAll

vlan configcontrol flexible

vlan members 1 50

vlan members 650 ALL

vlan ports 1-49 pvid 650

vlan configcontrol flexible

no auto-pvid

As I read i need to setup second dhcp pool with options 242 and on data vlan but I have whole bunches of Data vlans on Catalyst core switch  so I thought I can use only one dhcp pool with voice options working because I don't need data vlan on the avaya ers switch (working as a access switch for voice only)


Catalyst 4500 and Avaya phones

Where are the phones connected? Do they have dedicated ports or do your workstations connect to them?


*** Please rate all useful posts ***

HTH, John *** Please rate all useful posts ***

Catalyst 4500 and Avaya phones

phones were connected to avaya switch first [ phone ]-----[Avaya ers switch]----[Cisco Catalyst 4500]  

then I tested phone  directly  connected on the Catalyst 4500 -- same problem .

If I connect sip phone from another vendor (Vtech) it's getting ip easily and register to Avaya CM . So I think Avaya phone is looking for DHCP option 242 with vlan information first ->copying it to config file-> reboot and connect to proper vlan-> get ip from that vlan and register , BUT here in my case it doesnt work, I replaced phones -didn't help) , And I am thinking something is wrong  in the config of the Catalyst ... Right ? 

Catalyst 4500 and Avaya phones

I guess my question is, do you have a phone attached to the Catalyst directly and on an access port, or do you have the phone connected to a trunk port? If it's connected to an access port, remove "L2Q=1, L2QVLAN=650" from your 242 string and see if that helps.


*** Please rate all useful posts ***

HTH, John *** Please rate all useful posts ***
Super Bronze

Re: Catalyst 4500 and Avaya phones


The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.


Don't know if related, but some time ago we too had an issue with Avaya phones and (an older) Cisco switch.

The problem was, the Avaya Phones were trying to do LLDP with the Cisco switch, which the switch didn't support.  Basically the Avaya phones "hung" waiting for a reply from the switch (instead if timing out).

The fix was either/both (?) upgrading the Avaya firmware and the Cisco switch's IOS.  I recall (?) the Avaya upgrade had the phone time out LLDP (and continue) if they didn't get a LLDP reply and the Cisco switch NAK'ed LLDP.

New Member

Don't know if your switch

Don't know if your switch supports this command but use the command lldp run

CreatePlease to create content