QoS Practice Lab – LLQ

Ok so I have started some of the practice questions for me QoS exam at the end of Feb. I came across a good lab style question which I decided to answer using Cisco Packet Tracer.

Here is the requirement:

LLQ_LAB

I set this  up in Packet Tracer itself and here is my config on R1:

class-map match-all BULK
class-map match-all INTERACTIVE
class-map match-all VOICE
!
policy-map LLQ-POLICY
 class INTERACTIVE
 bandwidth 30
 class BULK
 bandwidth 16
 shape average 24000
 class VOICE
 priority 168
 class class-default
 fair-queue 
interface Serial0/0
 bandwidth 10000000
 ip address 10.1.1.5 255.255.255.252
 service-policy output LLQ-POLICY

Which I believe is correct for the requirement. One of the key points was the question specifies a ‘strict priority queue’ for voice. Therefore you must use the priority command in the policy to enable LLQ. Everything else was fairly straight forward.

Verify:

R1#show policy-map 
 Policy Map LLQ-POLICY
 Class INTERACTIVE
 Bandwidth 30 (kbps) Max Threshold 64 (packets)
 Class BULK
 Bandwidth 16 (kbps) Max Threshold 64 (packets)
 Traffic Shaping
 Average Rate Traffic Shaping
 CIR 24000 (bps) Max. Buffers Limit 1000 (Packets)
 Class VOICE
 Strict Priority
 Bandwidth 168 (kbps) Burst 4200 (Bytes)
 Class class-default
 Flow based Fair Queueing
 Bandwidth 0 (kbps) Max Threshold 64 (packets)

R1#show policy-map interface Serial 0/0
 Serial0/0
Service-policy output: LLQ-POLICY
Class-map: INTERACTIVE (match-all)
 0 packets, 0 bytes
 5 minute offered rate 0 bps, drop rate 0 bps
 Queueing
 Output Queue: Conversation 265
 Bandwidth 30 (kbps)Max Threshold 64 (packets)
 (pkts matched/bytes matched) 0/0
 (depth/total drops/no-buffer drops) 0/0/0
Class-map: BULK (match-all)
 0 packets, 0 bytes
 5 minute offered rate 0 bps, drop rate 0 bps
 Queueing
 Output Queue: Conversation 266
 Bandwidth 16 (kbps)Max Threshold 64 (packets)
 (pkts matched/bytes matched) 0/0
 (depth/total drops/no-buffer drops) 0/0/0
Class-map: VOICE (match-all)
 0 packets, 0 bytes
 5 minute offered rate 0 bps, drop rate 0 bps
 Queueing
 Strict Priority
 Output Queue: Conversation 264
 Bandwidth 168 (kbps) Burst 4200 (Bytes)
 (pkts matched/bytes matched) 0/0
 (total drops/bytes drops) 0/0
Class-map: class-default (match-any)
 7 packets, 2226 bytes
 5 minute offered rate 36 bps, drop rate 0 bps
 Match: any
 Queueing
 Flow Based Fair Queueing
 Maximum number of Hashed Queues 256
 Bandwidth 7500000 (kbps)Max Threshold 64 (packets)
 (total queued/total drops/no-buffer drops) 0/0/0
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Author: drbabbers

ccieme.wordpress.com - my personal journey to ccie