Traffic Shaping / Policing Question

I must have a problem with my configuration. Thanks in advance for the help.

I simply have some TDMoIP boxes (T1 to ethernet) on each side of a slow WAN link (approx 24Mbps). On each end of the WAN link is a

2620XL router running 12.2.40a. These routers have FastEthernet interfaces facing the WAN link. The TDMoIP boxes use 3Mbps of constant bandwidth. The customer has run fine for a few years, but has started seeing drops associated with high loads on their link.

My reasoning in setting up the service policy was that I needed to reserve (priority) 3 Mbps of traffic for the TDMoIP and then throttle the rest to an ammount less than the capacity of the WAN link.

So I create 2 classes: VOIP with priority 3072 and class-default with shape average 15000000. (using a total of 18Mbps). This should be well under the link capacity (24Mbps) and I should not see congestion.

When I apply the service policy, I can see the counters in each class respond as expected. Total traffic seems limited to approximately 18Mbps. But the TDM boxes suffer greatly when the link is loaded. All interactive traffic is also thwarted big time under shaping or policing.

I have tried nesting the service policies as seen in some examples on Cisco's page, but even then, the problems did not subside.

I have tried policing instead of shaping with various burst values for both.

Here is my config (its the same on both routers save for the source and destination are swapped for classifying the Voice traffic):

class-map match-all VoiceRAD match access-group 157 ! ! policy-map RadioLink_pmap class VoiceRAD priority 3072 class class-default shape average 15000000 ! interface FastEthernet0/0 ip address 172.31.1.121 255.255.0.0 service-policy output RadioLink_pmap ! access-list 157 permit ip host 10.35.1.10 host 10.34.9.95 access-list 157 permit ip host 172.31.1.121 any

I added the router's own IP in the access-list since it was my means of configuring the router. Even after adding it to the priority class, I would routinely wait 60-90 seconds for keystrokes to appear.

Here is the output of the show service policy int:

cte2600#show policy-map int FastEthernet0/0

Service-policy output: RadioLink_pmap

Class-map: VoiceRAD (match-all) 4716486 packets, 424579155 bytes 5 minute offered rate 2950000 bps, drop rate 0 bps Match: access-group 157 Queueing Strict Priority Output Queue: Conversation 264 Bandwidth 3072 (kbps) Burst 76800 (Bytes) (pkts matched/bytes matched) 4444/496383 (total drops/bytes drops) 0/0

Class-map: class-default (match-any) 1258995 packets, 1746625441 bytes 5 minute offered rate 14188000 bps, drop rate 0 bps Match: any Traffic Shaping Target/Average Byte Sustain Excess Interval Increment Rate Limit bits/int bits/int (ms) (bytes) 15000000/15000000 93750 375000 375000 25 46875

Adapt Queue Packets Bytes Packets Bytes Shaping Active Depth Delayed Delayed Active - 0 1259057 1746711591 226821 324632790 no

This snapshot was taken shorly after load was removed, but you can see the offered 5-minute rate was under the threshold set, and also the 5- minute load on the voice traffic was as expected (3Mbps) and has a drop rate of 0. The only thing odd that I noticed was the line: (pkts matched/bytes matched) 4444/496383 under the Voice section - I dont know what it means by matches - all

4.7 million packets in that policy should be considered for the class.

I thought policing would be better - just drop anything over 15000000 bps, but it didnt seem to work either.

I am at a loss of what to do next. I've tried a bunch of different ways to configure the shaping/policing without success.

Thanks again.