Provisioning Frame Relay
|Provisioning Frame Relay. The following table summarizes the major steps involved in provisioning a frame relay network.|
|Step 1||Choose a
committed Information Rate Based on Realistic, Anticipated Traffic Returns
All CIRs to Determine Core Bandwidth Requirements
the Link Speed and Number of Interfaces Required on the Core Router
|Step 4||Choose a
Router Platform that can Handle the Job
|Traffic Shaping Over Frame Relay.
While this presentation primarily focuses on features available in Cisco
devices, it still represents a good survey of traffic shaping features you
are going to want to consider.
Generally, Cisco's Frame Relay Traffic Shaping feature eliminates bottlenecks by providing high speed connections at the central site, with lower speed connections at the branch sites. In order to manage network congestion Cisco defines three performance measures.
The Frame Relay traffic shaping features should provide the following capabilities or some variant to improve scalability and performance.
|Rate Enforcement on a per VC Basis||You can configure a peak rate to limit
outbound traffic either to the CIR or to some other defined value,
such as EIR - excess information rate. Use rate enforcement to
|Generalized BECN Support on a per VC Basis||The router can monitor BECNs and
throttle traffic based on BECN marked packet feedback from the Frame
Relay network. The traffic is dynamically throttled based on
information contained in BECN tagged packets.
BECN based throttling is done by holding packets in the router's buffers to reduce data flow from the router to the Frame Relay network. This is done on a per VC basis and the transmission rate is adjusted based on the number of BECN tagged packets being received.
|PQ/CQ Support at a VC Level||The PQ/CQ Support feature at the VC
level allows for fine granularity in the prioritization and queueing
of traffic. These features improve scalability and performance
by increasing the density of virtual circuits and improving response
time. This applies to the Frame Relay PVCs and SVCs.
Custom queueing with per VC queueing and rate enforcement capabilities enable Frame Relay VCs to be configured to carry multiple traffic types (such as IP, SNA, IPX) with bandwidth guaranteed for each traffic type.
|All of these features require the router to buffer packets to control traffic flow and compute data rate tables. Because of this, router memory and CPU utilization must be adequate and configured so that the additional work to implement the features does not degrade overall Frame Relay performance.|