Cisco IP Telephony Troubleshooting Guide for Cisco CallManager Release 3.0(1)
© 2000 Cisco Systems, Inc.
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Documentation Checklist
Use the following checklist to be sure you have the proper documentation on your network
topology.
•
Topology that shows all network devices and critical components with port/interface
numbers to which they are attached, and what VLAN (if applicable) to which they
belong. Special designations should be used for ports that are in trunking or channeling
mode.
•
The root of the spanning-tree should be configured and all normally blocking ports
should be identified.
•
Any WAN circuits should be identified with the amount of bandwidth (CIR in the case of
frame-relay).
Note: The Cisco IP Phone 7960 has a 10/100-switched network port and a 10/100 PC port. Cisco
does not support “cascading” phones off of the PC port. We do not recommend attaching both
the network and PC ports to a switch (thereby creating a physical loop in the network).
Any WAN interface will require special consideration, since this is a potential source of
congestion. Cisco IP Phones and gateways set the RTP stream IP precedence field to five,
however this only tags the RTP packet. It is up to the network administrator to ensure that the
network is configured for prioritization and call admission control so that the Voice over IP
(VoIP) traffic can be serviced with minimal delay and contention for resources. For additional
information on this topic, see:
http://www.cisco.com/warp/public/793/voip/
