From: navaid@rogers.com
Date: Fri Sep 05 2003 - 11:14:32 GMT-3
Keep native vlan 1 for your trunk.
Make vlan 10,20,30,40 native for access ports based on your requirements.
Navaid
>
> From: "ccie2be" <ccie2be@nyc.rr.com>
> Date: 2003/09/05 Fri AM 10:00:31 EDT
> To: "Group Study" <ccielab@groupstudy.com>
> Subject: 3550 and IP Phone Verification
>
> Hi everyone,
>
> I want to confirm my understanding of the situation where IP Phones are
> connected to a 3550.
>
> Let's say that a firm has just upgraded their switches to Cat 3550's in
> preparation of a migration to IP Telephony. With the upgrade they have the
> same number of ethernet ports that they had with the old switches and their
> intention is to have all the PC's that were previously connected to the old
> switches connect via the access port on the IP Phone which in turn will be
> connected to the new Cat 3550 switches. Currently, their PC's reside in 4
> different vlans, vlan 10, 20, 30 and 40 and all of these vlans exist in each
> of their switches. Their plan is to have all the IP Phones in one voice vlan.
> And, they need the PC's to remain in whatever vlan they're already in after
> the migration.
>
> Can this be achieved?
>
> Based on what I understand, this can't be done. Here's the reason. Please
> correct me if I'm wrong on this.
>
> Data traffic from the PC's attached to the access port of the IP Phones is
> carried in untagged frames in the native vlan. While the native vlan can be
> assigned any vlan number there can be only 1 native vlan which, by default, is
> vlan 1. And, the native vlan must be the same on all the Cat 3550's since
> 802.1q trunks area being used.
>
> While this is my understanding from reading the 3550 config guide, this
> limitation doesn't seem reasonable or smart. Would Cisco design the 3550 so
> that PC's that were in different vlans would be forced to be in the same vlan
> if the PC's were connected via the IP Phone?
>
> Thanks; I greatly appreciate any help.
>
> dt
>
>
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