Junos question - why didn't this config work?

Hi all,

So, I have a EX2300 new switch stack (VC) that will be the new VoIP stack for our CA office; but, for setup, it is currently in our NJ office (where I am.) I programmed it up to support both data/voice traffic on two different VLANs, as I normally do (have done this before here in our NJ office with EX2200's) and, aside from some ELS syntax differences, it is about the same as I have done before. However, when I plugged in one of our VoIP phones, it lit up as it got PoE, but then refused to connect to our IP-PBX backend.

Not understanding why it did not work, I opened a case with JTAC, and we spent a bunch of time investigating things and trying some different config, all to no avail. But then, I thought to mention that as it is destined for our CA office, the voice VLAN there is a different number than the one in Princeton, and I had configured the voice VLAN using the CA number. As a test, we changed the voice VLAN number from the CA one (254) to the NJ one (50), and lo and behold, the phone connected!

Now, here's the thing -- the uplink port is configured on both sides as an access port (i.e., untagged), and not as a trunk. The Juniper VC stack is connected to an upstream Cisco Cat4500 system, thusly:

[ Cisco Cat 4510R+E ] (mode: access, VLAN: 50)------------[ IP-PBX ] | Gi2/44 (mode: access, VLAN: 50) | | ge-0/0/0 (mode: access, VLAN: 254) [ JNPR EX2300-48P VC ] | ge-0/0/46 (data VLAN: 2, voip VLAN: 254) | | LAN (voice) port [ IP phone ] 

And the relevant Junos config was:

interfaces { interface-range phoneports { member-range ge-0/0/1 to ge-1/0/47; unit 0 { family ethernet-switching { interface-mode access; vlan { members blackhole; } } } } ge-0/0/0 { unit 0 { family ethernet-switching { interface-mode access; vlan { members ca-voip; } storm-control default; } } } [...] switch-options { voip { interface phoneports { vlan ca-voip; forwarding-class assured-forwarding; } } } vlans { [...] } blackhole { vlan-id 2; } ca-voip { vlan-id 254; } [...] } poe { interface all; } 

And Cisco-side config:

! interface GigabitEthernet2/44 switchport access vlan 50 switchport mode access qos trust device cisco-phone service-policy input Phone-Ingress service-policy output Phone-Egress end ! 

And finally, the interface VLAN membership on the Juniper:

{master:0} l-wdennis@ca-voip-sw> show vlans Routing instance VLAN name Tag Interfaces [...] default-switch blackhole 2 [...] ge-0/0/46.0* [...] default-switch ca-voip 254 ge-0/0/0.0* [...] ge-0/0/46.0* [...] [...] 

All we did to get the phones to work was to switch the vlan-id under ca-voip from "254" to "50".

Since the frames should be (are) untagged on the access link between the Cisco and the Juniper, why would a VLAN number disparity kibosh the phone voip connection the set to the IP-PBX from working?

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(edit: formatting)