From: McClure, Allen (Allen.McClure@Yum.com)
Date: Fri Sep 05 2003 - 13:25:53 GMT-3
For 802.1q phones, this should be the appropriate configuration. In my
experience access subcommands (switchport access xxxxx) do not come into
play when the mode of a port set to trunk.
http://www.cisco.com/en/US/customer/tech/tk648/tk361/technologies_tech_n
ote09186a0080114aee.shtml
interface FastEthernet0/13
description phone and PC
switchport mode trunk
! Negotiation = bad for lab IMO. In RL it may be needed for
flexibility.
switchport trunk encapsulation dot1q
! If a phone talks trunking, it's dot1q, not ISL
switchport voice vlan 110
! Voice traffic on vlan 110
switchport trunk native vlan 10
! Data traffic on vlan 10 (native = untagged). Change this to change
vlans for the PC.
Matching the current PC access vlans of this firm with the native vlan
config should solve your issue. The native vlan is only significant to
the two ports forming the trunk and can thus be changed port by port.
I've been wrestling with this for a while myself and this is my current
solution. Any feedback is appreciated. Certainly would love to be
corrected if I'm wrong.
Allen G. McClure
CCNP/CCDP/MCSE
Yum! Brands, Inc.
Sr. Network Analyst
allen.mcclure@yum.com
-----Original Message-----
From: boby2kusa@hotmail.com [mailto:boby2kusa@hotmail.com]
Sent: Friday, September 05, 2003 10:58 AM
To: ccie2be; Group Study
Subject: Re: 3550 and IP Phone Verification
If theIP Phones are Cisco then:
switchport access vlan 10
switchport voice vlan 99 (just an example)
If non-Cisco IP Phone:
switchport trunk native 10 (for PC vlan)
switchport trunk encapsulation dot1q
----- Original Message -----
From: "ccie2be" <ccie2be@nyc.rr.com>
To: "Group Study" <ccielab@groupstudy.com>
Sent: Friday, September 05, 2003 7:00 AM
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
>
>
> ______________________________________________________________________
> _
> You are subscribed to the GroupStudy.com CCIE R&S Discussion Group.
>
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Wed Oct 01 2003 - 07:24:23 GMT-3