Because Systems Network Architecture (SNA) traffic and applications are
delay-sensitive, many users want to optimize the flow of SNA within their
network. Such optimizations fall into two categories:
There are no specific requirements for this document.
This document is not restricted to specific software and hardware
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
For more information on document conventions, refer to the
Cisco Technical Tips
Configure SNA permanent virtual circuits (PVCs) so that the %util =
100 and the minimum information rate (MIR) equal the desired committed
information rate (CIR) of the connection. This allows ForeSight to maintain
very short trunk queue depths.
Configure all SNA PVCs as high priority PVCs. This allows SNA
traffic to receive preferential treatment in the Frame Relay packet
assembler/disassembler (PAD) card (FRP) egress queue.
Set MIR=CIR=peak-rate-bps (PIR) (to as high a value as possible).
This allows the connection to receive CBR-like (or leased-line-like)
Groom SNA PVCs onto routes with the fewest number of hops or
routes, or both, with the shortest propagation
Make all SNA PVCs have COS=0, and all other PVCs have a higher class
of service (COs). This gives SNA PVCs the opportunity to reroute first.
Tune the network for best reroute performance. Cisco support
personnel have the expertise to do this.
Re-examine tuning periodically. For an overview of network tuning,
refer to Network Tuning in the
AutoRoute White Paper.
Groom SNA PVCs onto routes with the fewest number of