From: Yigit Zorlu (yzorlu@tepum.com.tr)
Date: Sun Nov 03 2002 - 07:56:15 GMT-3
Regarding to remote sites (that have less than 20 IP Phones) and/or non Cisco LANs
I think there are other ways to provide QoS when we are in the situaton that auxiliaryvlan is not possible. CoS and ToS are not necessarily used in 100 Mbps Ethernet LAN environment. They are tools to mark voice data for QoS policies. Unless we provide a policy for them they won't get any priority. We can provide the policy on the router for WAN. We can mark these packets on the WAN router since we know the IP address block of IP Phones. I believe QoS is needed on WAN transmission of voice data.
There is another point that I disagree. We can not easily configure remote site router which would act as DHCP server for IP Phones. Mostly there exists a firewall between main switch and WAN router. Since remote site have a limited number of users customers don't want to invest on another router or a server behind the firewall for DHCP purposes. Static assignment solves the problem.
Please someone correct me,
Yigit
PS: I agree that these topics are not directly related to CCIE prep. But QoS and voice concepts are gaining importance in labprep as well as real life situations.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Armand D
Sent: Sunday, November 03, 2002 2:25 AM
To: Tony H.; ccielab@groupstudy.com; tlarus@cox.net
Subject: Re: OT Probl relating to Interoperability of Cisco IP phones
with non-Cisco switc
Something else to consider with interoperability of
Cisco IP phones vs NON cisco phones are:
1- There is no CDP, and thus no advanced features
(Auxiliary VLAN, trust-ext, trust-device cisco ip
phone, power management, etc.).
2- So to place the phone and workstations in different
VLANs, which is possible, you must manually configure
the switch ports as trunks. This is much different
than Cisco's dynamic capabilities.
3- With Avaya or 3rd party solution you have to know
which ports to plug the phones into and make sure you
do not plug a workstation into a port that was
configured for a phone.
An interesting side note... We are also under the
impression that the 3rd party phones still do not have
any queuing nor any other way within the phone to
prioritize the voice traffic over the data (In
addition, they have NO mechanism to adjust the CoS
from the workstation. So we either have to trust the
phone and the workstation(s) attached to it or untrust
it all (eliminating L2 QoS). This is much different
from the Cisco solution, where the phones have built
in priority queues and we can communicate with the
phone to properly adjust any CoS settings from
attached workstation(s), thus creating an effective
trust boundary. With 3rd party solution (or the lack
thereof) transmit buffer congestion could occur at
multiple points leading to jitter, which of course,
leads to voice quality issues.
--- "Tony H." <aamercado31@yahoo.com> wrote: > From
ip phone to 3com switch, there may be several
> issues:
>
> 1. The CDP Mac address 0100.0ccc.cccc may causes
> problems..my guess is spanning tree??
>
> 2. Auto-negotiation issue but I would suspect it
> should be ok
>
> 3. Will 3com tagged ethernet frame thereby
> preserving
> preserve the CoS field? this may be dependent on the
> 3com sw???
>
> 4. 3com Inline power issue which cisco has at -48?
>
> The main issue is the 802.1Q. Setting trunk port,
> you maybe be able to get away with the different
> 802.1Q tags or otherwise, you can have a default
> vlan
> (no tag) and one tagged VLAN (say VlanID=200
> for phones) which means everybody in the same VLAN
> or
> use different ports on the switch (you need twice as
> many switch ports then).
>
> With the remote site question, I am assuming you
> have
> the central site doing dhcp but you can also have
> the
> remote router do dhcp with it pointing to the
> tftp/callmanager server at the central site. If it
> is
> a small site, then a dhcp router should be fine. If
> it
> is a larger remote site, you can put in another
> callmanager cluster but that would be getting away
> from your central design to distributed design or,
> like you said, you can manually program the phones
>
>
> --- Nigel Taylor <nigel_taylor@hotmail.com> wrote:
> > Yigit,
> > Another consideration would be dependant
> > on the size of the remote
> > site. This would be a consideration in that if
> the
> > remote site consist of
> > let's say 50-100 users then it's possible that
> > specific services like DNS,
> > DHCP and login servers(a BDC) would be located at
> > the remote site. This
> > would also be in lieu of the bandwisth/SLAs on the
> > WAN conection that exist
> > between your remote and central site.
> >
> > Nigel
> >
> > ----- Original Message -----
> > From: "Yigit Zorlu" <yzorlu@tepum.com.tr>
> > To: "Armand D" <ciscoworks2001@yahoo.com>; "Tony
> H."
> > <aamercado31@yahoo.com>; "Bob Usa"
> > <boby2kusa@hotmail.com>;
> > <tlarus@cox.net>; <ccielab@groupstudy.com>
> > Sent: Saturday, November 02, 2002 1:57 AM
> > Subject: RE: OT Probl relating to Interoperability
> > of Cisco IP phones with
> > non-Cisco switc
> >
> >
> > > I think Tom's question was "How can we configure
> > Cisco IP Phone in
> > non-cisco switch ?" e.g. with 3Com switch. It has
> to
> > be done in 3Com switch
> > as well. I believe that's one of the main reasons
> > Cisco started to
> > push/promote 802.1q instead of ISL. I believe in
> > that type of situation, it
> > is better to configure static IP address of and
> the
> > TFTP server address over
> > the IP Phone manually. I will give a try this
> week.
> > >
> > > And another question comes into my mind. What
> > happens do I have a
> > Multi-site Centralized IPTEL topology in remote
> > locations? How can remote
> > site IP Phones reach DHCP server ? I think in that
> > case also we need to
> > manually configure the phones.
> > >
> > > Am I missing something?
> > >
> > > Yigit
> > >
> > >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com
> > [mailto:nobody@groupstudy.com]On Behalf Of
> > > Armand D
> > > Sent: Friday, November 01, 2002 11:07 PM
> > > To: Tony H.; Bob Usa; tlarus@cox.net;
> > ccielab@groupstudy.com
> > > Subject: Re: OT Probl relating to
> Interoperability
> > of Cisco IP phones
> > > with non-Cisco switc
> > >
> > >
> > > Ok. Let me see if I understand.
> > >
> > > Does this solutoin as you have described, allow
> > for
> > > the Class of Service bit field to be set ? which
> > the
> > > switch will treat the phone and the data
> endpoint
> > > differentially ?
> > >
> > > Thanks,
> > >
> > > Armand
> > >
> > > --- "Tony H." <aamercado31@yahoo.com> wrote: >
> hi
> > > >
> > > > I have the opposite explanation (non ip phone
> to
> > > > cisco
> > > > switch)...maybe it will give you some insight.
> > > >
> > > > If the ip phone does not send CDP, then you
> will
> > > > have
> > > > problems in recognizing the voice VLAN:
> > > >
> > > > The workaround is to use DOT1Q trunking with
> the
> > PC
> > > > data frames as Untagged, while the Voice
> frames
> > are
> > > > Tagged with VLAN Headers.
> > > >
> > > > However you may (or may not need to configure
> > the
> > > > non-cisco ip phone) For instance in the Avaya,
> > you
> > > > probably need to configure the following:
> > > > 802.1Q = on (default is probably off)
> > > > Vlan ID = your voice vlan #
> > > >
> > > > On the Cat:
> > > > set trunk to dot1Q
> > > > set your vlans
> > > > clear all unneeded vlans off the trunk
> > > >
> > > > For example on a CATIOS (ie 35xx/29xx)
> > > >
> > > > interface FastEthernetx/x
> > > > switchport trunk encapsulation dot1q
> > > > switchport trunk native vlan 200
> > > > switchport mode trunk
> > > > switchport voice vlan 100
> > > > spanning-tree portfast
> > > > no cdp enable
> > > >
> > > > This is what will happen:
> > > >
> > > > The PC traffic be treated as native (data)
> > untagged
> > > > while the ip phone (in this case Avaya) would
> > tag
> > > > voice traffic with the voice VLAN header info
> > and
> > > > send
> > > > it (802.1Q) out the port to the Cat. It
> should
> > pass
> > > > on both tagged and untagged frames. The Cat
> will
> > see
> > > > both and do what it is suppose to do as a
> trunk
> > port
> > > > and segregate voice from data
> > > >
> > > > Hope it helps.
> > > >
> > > >
> > > > --- Bob Usa <boby2kusa@hotmail.com> wrote:
> > > > > It depends on what kind of platform. For
> > > > > 3500XL/2900XL devices you will have
> > > > > to set up the port/interface fro dot1q
> > trunking
> > > > and
> > > > > set the native vlan for
> > > > > the data vlan. Non-Cisco IP phone such as
>
=== message truncated ===
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