Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Traffic Shaping Problem

IOS 12.2(13)T3

When I enable traffic shaping 1 PVC (out of 37 total) experiences substantial drops and increase in latency.

Here's the relevant config:

ip cef

interface Hssi1/0

encapsulation frame-relay

no ip mroute-cache

serial restart_delay 0

cdp enable

frame-relay traffic-shaping

frame-relay lmi-type cisco

frame-relay ip rtp header-compression passive

interface Hssi1/0.27 point-to-point

ip address (omitted)

ip mtu 1500

ip ospf network point-to-multipoint

ip ospf cost 150

frame-relay interface-dlci 102

class FRCLASS_512

map-class frame-relay FRCLASS_512

frame-relay cir 512000

frame-relay bc 5120

frame-relay be 0

frame-relay mincir 512000

I tried reducing the CIR to 384 and 128 - just in case the provider info was incorrect, but it didn't help.

Other possibly relevant info: One of the PVCs is carrying voice so I have a policy built, and I am also using RTP Header compression on the HSSI interface.

Any help would be greatly appreciated.

New Member

Re: Traffic Shaping Problem

It's the MinCIR you need to reduce not the CIR. CIR is the access rate.

New Member

Re: Traffic Shaping Problem

They were both reduced.

Doesn't matter though - I worked out the solution with TAC today. It turns out the service provider was not policing their individual PVCs, so the overall throughput per PVC was much higher prior to traffic shaping. When I enabled traffic-shaping it forced the PVCs to abide by the CIR and high utilization links were suffering loss. The solution was to configure a CIR for the PVCs to the interface speed (to 44mbs, essentially wide open), set the mincir to the provider CIR (128k, 512k, depending on the PVC), and enable adaptive shaping becn. Worked like a charm...