Troubleshooting guide

CHAPTER
9-1
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
9
Troubleshooting CES Connections and
Network Clocking
This chapter provides troubleshooting information for connectivity problems in circuit emulation service
(CES) environments and network clocking. For more information on CES, refer to the “Circuit
Emulation Services and Voice over ATM” chapter in the Guide to ATM Technology, and “Configuring
Circuit Emulation Services” chapter in the ATM Switch Router Software Configuration Guide.
Before you begin, make sure that all physical port connections are working correctly. For information
on troubleshooting interfaces, refer to Chapter 5, “Troubleshooting Switch Router ATM
Interface Connections.”
This chapter contains the following sections:
• CES Overview, page 9-1
• CES Example Network, page 9-4
• Initial Troubleshooting of CES, page 9-4
• Troubleshooting CES Using debug Commands, page 9-7
• Troubleshooting Network Clocking, page 9-7
CES Overview
CES allows circuits to be transparently extended across an ATM network. CES is typically used to
transport voice or video between the ATM switch router and non-ATM telephony devices, such as PBXs
and TDMs, or video devices. Voice and video, unlike data traffic, are very sensitive to delay and delay
variance. CES uses constant bit rate (CBR) virtual circuits (VCs), which guarantees acceptable delay and
delay variation and thus satisfies the requirements of voice and video traffic.