From: Scott Morris (smorris@ipexpert.com)
Date: Fri Oct 26 2007 - 12:33:20 ART
IP Telephony itself isn't part of the lab, but familiarity with some of the
topics is a "good thing to know". :)
In a nutshell, your voice vlan is sent with an 802.1Q tag and your PC/Data
traffic is sent untagged. In a "pure trunk" concept this means your PC data
would be your native vlan and you'd have a trunk running.
For security purposes, people used to get all up in arms about needing to
use "switchport trunk allowed" and restrict what things could or could not
be sent over that trunk for the great fear of hackers. Cisco has made it
simpler with most switches where you can now simply be in 'switchport mode
access'.
This, when we look at it, doesn't allow trunking. The 'switchport voice
vlan' command, however, provides a specific override allowing tagging of one
single vlan only. So we've made things better for the security conscious as
well as simpler for the configuration.
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, JNCIS-ER, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
VP - Technical Training - IPexpert, Inc.
IPexpert Sr. Technical Instructor
A Cisco Learning Partner - We Accept Learning Credits!
smorris@ipexpert.com
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
http://www.ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gregory Gombas
Sent: Friday, October 26, 2007 11:27 AM
To: Cisco certification
Subject: IP Telephony Topics for R+S
Not sure if IP telephony is in scope for the R+S but seems to crop up in the
IE workbooks a lot. I was hoping someone could help clear up some confusion:
1. When connecting an cisco IP phone to a 3550/3560, does it automatically
create an 802.1q trunk?
2. According to the DOC cd:
"You can configure an access port with an attached Cisco IP Phone to use one
VLAN for voice traffic and another VLAN for data traffic from a device
attached to the phone. "
How is it possible two have two different VLANS run over a switch port
configured in access mode?
3. Can someone recommend some good (but short) reads for connecting IP
telephones to Cisco switches? I already have this one:
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3560/12240se/scg/swvo
ip.htm
Thanks,
Greg
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