From: Keane, James (James.Keane@agriculture.gov.ie)
Date: Mon Jun 27 2005 - 05:40:44 GMT-3
Guys I was a little surprised when I saw this thread, I appreciate that a point is being made that the phone will work on access but according to the documentation I have read you should leave the trunking to default
switchport mode dynamic
and the switch sorts it out .. am I completely bonkers ?
I think thats what I am going to do anyways !
-----Original Message-----
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From: Ed Lui [mailto:edwlui@gmail.com]
Sent: 26 June 2005 06:02
To: Chris Lewis (chrlewis)
Cc: ccielab@groupstudy.com
Subject: Re: Voice VLAN - Access ports
Hi Chris,
I also have a copy of the book(Maurilio Gorito's routing and switching
practice lab book by Cisco press).I do have to agree with you about "that is
what Maurilio gave in his book, and likely what they would be looking for on
the lab exam, which is the purpose of this list "
On the other hand, though I don't have this book(Cisco Press book Cisco
Catalyst QoS, by Flanagan et al,). I would think the author means the phone
is actually connected to an access port (see underlined).
"Through the use of dot1q trunks, *voice traffic from an IP phone connected
to an access port* can reside on a separate VLAN and subnet. The workstation
attached to the Ip phone might still reside on the access, or native
VLAN........Subsequently, with the use of voice VLANs, all traffic is tagged
to and from the Cisco IP phone and Catalyst switch."
Anyway, since you work for Cisco. If by any chance you know Maurilio's
e-mail address. I would not mind to send him an e-mail, just to figure out
what is the difference between the trunk port and access port.
Thanks, :)
Ed Lui
On 6/25/05, Chris Lewis (chrlewis) <chrlewis@cisco.com> wrote:
> Hi Ed,
> Thanks for the reply, this has been a valuable exchange for me, as it has
> made me rethink some things. However, please consider that Cisco
> documentation on the web is imperfect, sometimes it is accurate from one
> point of view, but can easily lead to incorrect conclusions, and sometimes
> it is flat out wrong and won't work (my favorite current example is the
> configuration for Outbound Route Filtering, it is missing the reference to
> the prefix list, without which it does not work). Cisco documentation on the
> web is a tremendous resource, but it should only be taken as a guide for
> what the starting point for configuration in a lab should be IMHO.
> The best configuration example I have seen of voice vlan comes from
> Maurilio Gorito's routing and switching practice lab book by Cisco press. In
> practice lab 2, configurations are shown for connecting a 7960 that does
> trunking, and a 7905 that does not do trunking.
> The port connecting to a 7960 is configured for trunking, and the port
> connected to the 7905 is not. This is given on p96
> 3550 config for 7960 phone
> int fa0/16
> switchport access vlan 2
> switchport trunk encapsulation dot1q
> switchport trunk native vlan 2
> switchport mode trunk
> switchport voice vlan 50
> no ip address
> duplex full
> speed 100
> spanning-tree portfast
> 3550 config for 7905 phone
> int fa0/17
> switchport access vlan 50
> no ip address
> duplex half
> speed 10
> The explanation is given as follows:
> The 7960 has the capability to trunk to the 3550 as it has an on-board 3
> port switch and can separate the voice and data traffic
appropriately.The7905 phone only has 10 base T and needs manual insertion in
to the voice
> vlan. Ensure that the port connecting to the 7960 is configured as a trunk
> using dot1q and that the native vlan is 2.
> If you also look at the Cisco Press book Cisco Catalyst QoS, by Flanagan
> et al, on page 63 you see the following:
> "Through the use of dot1q trunks, voice traffic from an IP phone
> connected to an access port can reside on a separate VLAN and subnet. The
> workstation attached to the Ip phone might still reside on the access, or
> native VLAN........Subsequently, with the use of voice VLANs, all traffic is
> tagged to and from the Cisco IP phone and Catalyst switch."
> Now one could argue that things like portfast are not needed for a trunk
> mode in this configuration, and I would agree, but that is what Maurilio
> gave in his book, and likely what they would be looking for on the lab exam,
> which is the purpose of this list :)
> I think there are at least two sources of confusion in this
> documentation. First is that not all IP phones are created equal, some do
> trunking and some don't. The other is a potential dual use of the phrase
> access port. In some contexts it can mean a non trunnking port, in others it
> can mean an ethernet port (which can be configured for trunking or
> non-trunking).
> Cheers
> Chris
>
> ------------------------------
> *From:* Ed Lui [mailto:edwlui@gmail.com]
> *Sent:* Saturday, June 25, 2005 12:27 AM
> *To:* Chris Lewis (chrlewis)
> *Cc:* John Matus; gladston@br.ibm.com; ccielab@groupstudy.com
> *Subject:* Re: Voice VLAN - Access ports
>
> Chris,
> I have been struggling about 2 vlans on an access port for a while. I
> know it works with either access port or trunk port let say with a 7960.
> What I understand is, an access port can not carry traffic for more than 1
> vlan. Somehow, the documentation told me voice vlan is an exception. Then I
> labbed it up myself(3550 EMI + 7960). The result is an access port can carry
> data on one vlan and voice on another within the same access port. And that
> is what the documentation said, too.
> Consider those underlined below. Portfast is for access port and not for
> trunk port.
> Voice VLAN Configuration Guidelines
>
> These are the voice VLAN configuration guidelines:
>
> - *You should configure voice VLAN on switch access ports.*
> - Before you enable voice VLAN, we recommend that you enable QoS on
> the switch by entering the mls qos global configuration command and
> configure the port trust state to trust by entering the mls qos
> trust cos interface configuration command.
> - *The Port Fast feature is automatically enabled when voice VLAN is
> configured*. When you disable voice VLAN, the Port Fast feature is
> not automatically disabled.
>
> Per your config :
> Int fa0/16
> Switch access vlan 2
> Switch trunk encap dot1q<---to be removed----->
> Switch trunk native vlan 2<---to be removed----->
> Switch mode trunk<---to be removed----->
> Switch voice vlan 50
> switchport priority extend cos 0
> mls qos trust cos < or "mls qos trust device cisco-phone" should also work
> >
> It works with those lines removed. But also WORKS WITH THOSE LINES. I am
> so confuse about the configurations. Wish someone can explain the Pros and
> Cons between the 2. Finally, I also have the same book you guys have and
> understand it says trunk port configuration needs to be included. On the
> other hand, documentation from cisco.com <http://cisco.com/> said access
> port.
> :)
> Ed Lui
>
>
> On 6/24/05, Chris Lewis (chrlewis) <chrlewis@cisco.com> wrote:
> >
> > Hi,
> >
> > John, that is correct, the 7960 uses trunking, the cheaper ones do not.
> >
> > Ed, my question to you is if you are told to configure a switch port to
> > have voice traffic from the phone in vlan 50 and data traffic from a PC
> > attached to the phone in vlan 2, how can you do that without configuring
> > trunking on the port? Clearly you would not want data traffic rom the PC
> >
> > in the same vlan as the voice traffic, otherwise it ceases to be a voice
> > vlan :)
> >
> > Chris
> >
> > -----Original Message-----
> > From: John Matus [mailto:jmatus@pacbell.net ]
> > Sent: Friday, June 24, 2005 9:32 PM
> > To: Ed Lui; Chris Lewis (chrlewis)
> > Cc: gladston@br.ibm.com; ccielab@groupstudy.com
> > Subject: Re: Voice VLAN - Access ports
> >
> > my ciscopress lab book is in the car...........but....
> > i think it all depends on which type of phone you are using.
> >
> > i believe that the cheapy phones actually use the "switch access vlan"
> > for their traffic and a more expensive one <if i can remember correctly,
> >
> > the 7960 phone??> uses trunking.
> >
> >
> > Regards,
> >
> > John D. Matus
> > MCSE, CCNP
> > Office: 818-782-2061
> > Cell: 818-430-8372
> > jmatus@pacbell.net
> > ----- Original Message -----
> > From: "Ed Lui" <edwlui@gmail.com>
> > To: "Chris Lewis (chrlewis)" <chrlewis@cisco.com>
> > Cc: < gladston@br.ibm.com>; <ccielab@groupstudy.com>
> > Sent: Friday, June 24, 2005 6:34 PM
> > Subject: Re: Voice VLAN - Access ports
> >
> >
> > > Chris,
> > > It doesn't sound like what I learned from the DocCD. According to the
> > > DocCD. Switch port connected to IPphone should be configured as access
> >
> > > port
> > > and NOT TRUNK. Take a look :
> > > Voice VLAN Configuration Guidelines
> > >
> > > These are the voice VLAN configuration guidelines:
> > >
> > > - You should configure voice VLAN on switch access ports.
> > > - Before you enable voice VLAN, we recommend that you enable QoS on
> > > the switch by entering the mls qos global configuration command and
> > > configure the port trust state to trust by entering the mls qos
> > trust
> > > cos interface configuration command.
> > > - The Port Fast feature is automatically enabled when voice VLAN is
> > > configured. When you disable voice VLAN, the Port Fast feature is
> > not
> > > automatically disabled.
> > > - When you enable port security on an interface that is also
> > > configured with a voice VLAN, you must set the maximum allowed
> > secure
> > > addresses on the port to at least two.
> > > - If any type of port security is enabled on the access VLAN,
> > dynamic
> > > port security is automatically enabled on the voice VLAN.
> > > - You cannot configure static secure or sticky secure MAC addresses
> > on
> > > a voice VLAN.
> > > - Voice VLAN ports can also be these port types:
> > > - Dynamic access port. See the "Configuring Dynamic Access Ports
> > > on VMPS Clients"
> > >
> > section<
> > http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12114e
> > a1/35
> > > 50scg/swvlan.htm#94106>for
> > > more information.
> > > - Secure port. See the "Configuring Port Security"
> > >
> > section<http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12114e
> > a1/35
> > > 50scg/swtrafc.htm#86378>for
> > > more information.
> > > - 802.1X authenticated port. See the "Using 802.1X with Voice
> > > VLAN Ports"
> > >
> > section<http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12114e
> >
> > a1/35
> > > 50scg/sw8021x.htm#50544>for
> > > more information.
> > > - Protected port. See the "Configuring Protected Ports"
> > >
> > section<http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12114e
> > a1/35
> > > 50scg/swtrafc.htm#56161>for
> > > more information
> > >
> > > HTH,
> > > Ed Lui
> > >
> > > On 6/24/05, Chris Lewis (chrlewis) < chrlewis@cisco.com> wrote:
> > >>
> > >> This is a config that I believe works to make vlan 50 the voice vlan,
> > >> and vlan 2 to be the data vlan, then sets data from the PC to CoS 0
> > and
> > >> trusts CoS from the phone.
> > >>
> > >> Mls qos
> > >>
> > >> Vlan 50
> > >> Name voice vlan
> > >>
> > >> Int fa0/16
> > >> Switch access vlan 2
> > >> Switch trunk encap dot1q
> > >> Switch trunk native vlan 2
> > >> Switch mode trunk
> > >> Switch voice vlan 50
> > >> switchport priority extend cos 0
> > >> mls qos trust cos
> > >>
> > >> The switch access configuration in the interface defines what vlan
> > the
> > >> port belongs to if for some reason the port stops trunking. Voice
> > vlan
> > >> has to work on a trunk port for there to be traffic that are members
> > of
> > >> two vlans on it.
> > >>
> > >> It could be possible that the documentation you refer to is listing a
> > >> restriction for configuring port security in addition to voice vlan,
> > >> although I don't know for sure.
> > >>
> > >> Chris
> > >>
> > >> -----Original Message-----
> > >> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com ] On Behalf
> > Of
> > >> gladston@br.ibm.com
> > >> Sent: Wednesday, June 22, 2005 12:14 PM
> > >> To: ccielab@groupstudy.com
> > >> Subject: Voice VLAN - Access ports
> > >>
> > >> Hi,
> > >>
> > >> Looking for Port security information I read this:
> > >>
> > >> "Voice VLAN is only supported on access ports and not on trunk ports,
> >
> > >> even though the configuration is allowed"
> > >>
> > >>
> > http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12225seb/scg/s
> >
> > >> wtrafc.htm#wp1038501
> > >>
> > >> Some time ago I was researching about this subject (if it would be
> > >> allowed to configure an interface connected to an IPPhone with
> > >> 'switchport mode trunk').
> > >> One of the answers was 'yes'.
> > >>
> > >> Do you know if an IPPhone only works if the port is configured as
> > access
> > >> port?
> > >> If yes, how does it work, considering the previous Cisco statement?
> > >>
> > >> Thanks for any feedback.
> > >>
> > >>
> > _______________________________________________________________________
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> > >>
> > _______________________________________________________________________
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> > >
> > _______________________________________________________________________
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