Frf.12 - HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual

Rate limiting defines the maximum amount of bandwidth a PVC is allowed to
consume. You can set different rate limits for when the line is congested and
when it is free.

FRF.12

When running voice or other real-time, delay-sensitive applications over a
Frame Relay interface, you may want to fragment Frame Relay frames.
Fragmenting frames reduces latency and improves performance. You should
use fragmentation for lower-speed connections, particularly those with
speeds of 512 Kbps or less.
VoIP traffic is sensitive to delay. The quality of a voice transmission is seriously
decreased if its delay is more than 150 ms. Transmission delays accumulate
at several points: they include, for example, the time it takes the router to
process and encapsulate a frame and to transmit the frame across the WAN
connection.
Without Frame Relay fragmentation
Router
VoIP Data frame
With Frame Relay fragmentation
Router
VoIP Data frame
Figure 7-7. Frame Relay Fragmentation
Serialization delay is the time it takes the router to transmit data out an
interface. The larger the frame, the longer it takes to serialize it. VoIP frames
are relatively small and have a short serialization delay, which maintains the
quality of the voice stream at the other end of the link. However, large data
frames can clog the interface, delaying VoIP frames as well. Frame Relay
fragmentation reduces the times it takes to serialize large data frames by
breaking large data frames into smaller frames. VoIP frames can then be
interleaved among the fragments. (See Figure 7-7.)
Configuring Rate Limiting for Frame Relay
VoIP Data frame
Serialization
delay
Frag Frag VoIP Frag
Setting Up Quality of Service
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