prioritization of traffic doesn't work with on frame-relay.

router A: Access-rate 128k CIR 128k

router B: Access rate 256k CIR 128k

****Problem description: Both routers are configured with Frame-relay traffic shaping and LLQ. However, priority queue doesn't seem to work at all. During high volume of traffic, the priority policy doesn't seem to provide guaranteed bandwidth as configured. The prioritized traffic became slow and high latency during high network utilization(100%)

****Questions:

1. Does prioritization work with frame-relay traffic shaping? AFAIK it should work.
2. configuration error that i missed?
3. Any logical explaination for this behavior?
4. maybe an ios bug?

****logs routerA#sh frame pvc zzz

PVC Statistics for interface Serial0/0 (Frame Relay DTE)

DLCI = zzz, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0.2

input pkts 47057 output pkts 38473 in bytes 38948050 out bytes 8096495 dropped pkts 0 in pkts dropped 0 out pkts dropped 0 out bytes dropped 0 in FECN pkts 27439 in BECN pkts 0 out FECN pkts 0 out BECN pkts 0 in DE pkts 0 out DE pkts 0 out bcast pkts 531 out bcast bytes 82836 pvc create time 3w3d, last time pvc status changed 3w3d cir 128000 bc 128000 be 0 byte limit 2000 interval

Service-policy output: llq

Class-map: prioritized_app (match-all) 930 packets, 60810 bytes 5 minute offered rate 0 bps, drop rate 0 bps Match: access-group name prioritize_traffic Queueing Strict Priority Output Queue: Conversation 24 Bandwidth 48 (kbps) Burst 1200 (Bytes) (pkts matched/bytes matched) 43/2728 (total drops/bytes drops) 0/0

Class-map: email_guaranteed (match-all) 17046 packets, 3086019 bytes 5 minute offered rate 15000 bps, drop rate 0 bps Match: access-group name guarantee_email Queueing Output Queue: Conversation 25 Bandwidth 32 (kbps) Max Threshold 64 (packets) (pkts matched/bytes matched) 1551/1143994 (depth/total drops/no-buffer drops) 0/0/0

Class-map: class-default (match-any) 20498 packets, 4950246 bytes 5 minute offered rate 5000 bps, drop rate 0 bps Match: any Output queue size 0/max total 600/drops 0

PVC Statistics for interface Serial1/3 (Frame Relay DTE)

DLCI = yyy, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial1/3.1

input pkts 13586 output pkts 16712 in bytes 2938380 out bytes 13615274 dropped pkts 0 in FECN pkts 0 in BECN pkts 0 out FECN pkts 0 out BECN pkts 0 in DE pkts 0 out DE pkts 0 out bcast pkts 180 out bcast bytes 10080 pvc create time 9w6d, last time pvc status changed 3w0d cir 128000 bc 128000 be 0 byte limit 2000 interval

Service-policy output: llq

Class-map: prioritized_app (match-all) 334 packets, 21976 bytes 30 second offered rate 0 bps, drop rate 0 bps Match: access-group name prioritize_traffic Weighted Fair Queueing Strict Priority Output Queue: Conversation 24 Bandwidth 48 (kbps) Burst 1200 (Bytes) (pkts matched/bytes matched) 328/20771 (total drops/bytes drops) 0/0

Class-map: email_guaranteed(match-all) 9342 packets, 11018829 bytes 30 second offered rate 109000 bps, drop rate 0 bps Match: access-group name guarantee_email Weighted Fair Queueing Output Queue: Conversation 25 Bandwidth 32 (kbps) Max Threshold 64 (packets) (pkts matched/bytes matched) 9049/10732217 (depth/total drops/no-buffer drops) 9/0/0

Class-map: class-default (match-any) 7031 packets, 2575469 bytes 30 second offered rate 14000 bps, drop rate 0 bps Match: any Output queue size 23/max total 600/drops 5

Please do let me know if further information is needed.

Thanks in adv.

Hi,

Here is the relevant bits from my config which does work:-

class-map match-any VOIP match access-group name VOIP-ACL ! policy-map QOS-POLICY class VOIP priority 144 class class-default fair-queue ! interface Serial0/0 bandwidth 192 no ip address encapsulation frame-relay ip route-cache flow no keepalive cdp enable frame-relay traffic-shaping frame-relay ip rtp header-compression hold-queue 1024 out ! interface Serial0/0.1 point-to-point bandwidth 192 ip address 10.27.13.3 255.255.255.0 no ip mroute-cache frame-relay interface-dlci 103 class 192k-VoiceLLQ frame-relay ip rtp header-compression ! ip access-list extended VOIP-ACL permit ip any any dscp af11 permit ip any any dscp ef ! map-class frame-relay 192k-VoiceLLQ frame-relay cir 192000 frame-relay bc 19200 frame-relay be 0 frame-relay mincir 192000 frame-relay fragment 400 service-policy output QOS-POLICY

James

I notice:-

I have had issues getting LLQ to work on a few platforms. IIRC 837, 3725 over Dialer interfaces.

I have come to the conclusion that it is not supported but can find EXACTLY no documentation on the matter.

I can configure it and do sh policy-map and all looks OK-ish. Thing is there is no actual queuing recorded and testing reveals that QoS (let's say) is not actually working.

On the other hand I have got LLQ with hierarchical policy maps (ie LLQ over traffic shaping) working on tunnel interfaces on 877 and 2811) and this works beautifully.

Anyway I am highly disolusioned about the whole Cisco QoS story now since I have the impression that it is impossible to figure out what might work without trying it on the exact platform and release that you propose to use.

I did not ask TAC, I think due to our supoprt having run out unexpectedly due to a change in personnel.

I can't seem to find any problem on my configuration. show policy-map int also shows that it is working although in reality it doesn't seem to work as prioritization should reserve the bandwidth allocated in case of congestion.

During my troubleshooting, i noticed that cef is not turned on on both of my routers. I am wondering if this is the problem.

Can anyone confirm that this CEF is needed on 3600 and 2600 for my configs to work.

Thanks.

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