White Paper Abstract:
Voice over IP (VoIP) over Integrated Service Digital Network (ISDN) is sometimes a desirable combination, especially in enterprise networks using IP Telephony. The features required to provide necessary quality of service (QoS) for VoIP, Low Latency Queuing (LLQ), Class Based Weighted Fair Queuing (CBWFQ), and Link Fragmentation and Interleaving (LFI), are supported for ISDN and the combination works. However, there are significant design considerations to take into account. This document discusses the caveats and limitations involved in using these VoIP related QoS features with ISDN, and provides some tested sample configurations.