3com / CISCO migration issue

Hi,

We have a mitle phone switch that we moved to the new cisco core. Now phones struggle to pick up DHCP but once up and running are fine and communicate with the mitle switch as expected.

the 3 com config was

interface GigabitEthernet2/0/5
port link-mode bridge
description Mitel 3300 Controller
port link-type hybrid
port hybrid vlan 10 tagged
port hybrid vlan 1 untagged
broadcast-suppression pps 3000
undo jumboframe enable
stp edged-port enable

and the new CISCO is

interface GigabitEthernet1/2/3
description Mitel 3300 Controller
switchport
switchport mode trunk
spanning-tree portfast edge
end

vlan 1 being native will be untagged and 10 is allowed if tagged right?

I put a trace on the port G1/2/3 and I see DHCP packets getting sent to the mitel Switch, but just no replies?

any ideas ?

Cheers

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Comments

it_consultant

The DHCP is going over vlan 1 or 10?

DevilWAH

LLDP/DCP pushes phone to vlan 10 and DHCP runs over that.

RouteMyPacket

Using VLAN 1 eh? That's another discussion...back at it..yes VLAN 1 will be native and untagged, I would need more detail but do you have an ip helper-address configured to allow clients to get DHCP from the other network segment?

If you do a sh int trunk, are you spanning your appropriate vlans across that trunk?

it_consultant

DevilWAH wrote: »

LLDP/DCP pushes phone to vlan 10 and DHCP runs over that.

Obvious question then, is LLDP configured properly for those ports in accordance with MITEL's specifications?

I am assuming the VLAN set up is OK since you indicated that once the phone obtains an IP either manually or automatically it works fine. If the problem was a VLAN it would never work.

*EDIT*

Although on your Cisco port config I would expect to see something like this:

switchport mode trunk
switchport native vlan 1
swithchport allowed vlan 10 add tagged

Or something like it, that is the Brocade ISP switch syntax but it is broadly similar. This would replicate the 'hybrid' mode the 3COM supports.

DevilWAH

RouteMyPacket wrote: »

Using VLAN 1 eh? That's another discussion...back at it..yes VLAN 1 will be native and untagged, I would need more detail but do you have an ip helper-address configured to allow clients to get DHCP from the other network segment?

If you do a sh int trunk, are you spanning your appropriate vlans across that trunk?

umm I don't need an IP helper as the mitle switch which is the DHCP server is also in VLAN 10
and who' s using vlan1? Vlan 1 is an unused vlan (well not strictly true I use it in some places for authentication tasks)

DevilWAH

it_consultant wrote: »

*EDIT*

Although on your Cisco port config I would expect to see something like this:

switchport mode trunk
switchport native vlan 1
swithchport allowed vlan 10 add tagged

Or something like it, that is the Brocade ISP switch syntax but it is broadly similar. This would replicate the 'hybrid' mode the 3COM supports.

On cisco the naivice vlan is by default 1 so the config is there but hidden, and in this case I have allowed all vlans on the trunk link so they will all be tagged (apart from vlan 1).

I should add I stripped out a load of config and made it as simple as possible while trouble shooting I don't normally allow all vlans on a trunk unless they are needed.