This series of interactive documents uses a typical head office and branch
office in order to demonstrate some common voice network configurations. This
interactive diagram allows you to view network configurations:
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Click a component to view configuration
and troubleshooting information.
Refer to Unified CallManager Interactive Voice Network Configuration and Troubleshooting Case Study for requirements assumed by this series of interactive documents.
This configuration assumes that the Frame Relay PVC between the San Jose head office and RTP remote office is 256Kbps. The requirement for voice is to guarantee 2 x G.729 calls across the Frame Relay circuit even at times of traffic congestion.
This configuration example follows the recommendations stated in the Network Infrastructure chapter in Cisco Unified Communications SRND Based on Cisco Unified CallManager 4.x and the WAN Aggregator section of the Enterprise QoS Solution Reference Network Design Guide Version 3.3, as well as the Branch Router QoS design.
The parameters in this section are used based on Cisco's best practices in the SRNDs. For more information, refer to table 3-1 in the WAN Aggregator section of the Enterprise QoS Solution Reference Network Design Guide Version 3.3.
For slow-speed (768 kbps) Frame Relay links:
FRF.12 with Fragment size of 320 Bytes
Enable cRTP (Real-time Transport Protocol Header Compression)
This example uses this configuration:
Link Speed 256Kbps CIR = 95% of PVC speed = 243200bps BC = 2432 Bits per Tc Frame Relay Traffic Shaping LLQ or Low Latency Queuing
Note: Locations-based CAC does not take into account bandwidth used by multicast MOH. Therefore, if you provision CAC for 2 x G.729 calls and have placed two calls over the WAN, multicast MOH is still permitted over the WAN. This will result potentially in poor audio quality for your existing calls. In order to prevent this from happening, make sure you provision extra bandwidth for each multicast session over the WAN. For more information, refer to the Call Admission Control and the Music on Hold sections in Cisco Unified Communications SRND Based on Cisco Unified CallManager 4.x.
Use the Voice Codec Bandwidth Calculator (registered customers only) for 2 x G.729 calls with Frame Relay and cRTP our total bandwidth required is 24.36 kbps. An additional multicast stream requires 36.54 Kbps for the priority queue. Take into account an additional multicast stream brings up the total bandwidth required to 36.54 Kbps for the priority queue. Make this 50Kbps since it is still less than 33% of the total bandwidth of 256Kbps. (The recommendation for voice traffic in the priority queue should not exceed 33% of the total bandwidth.)
With regard to other traffic queues, use 8 kbps for signaling, as stated in the SRND recommendation for calls less than 10, and the remainder of the traffic is placed in weighted fair queue.
San Jose Router
hostname SanJose ! !--- Refer to the Network Infrastructure chapter in the SRND class-map match-any ctraffic !--- Match voice signaling for DSCP 24 and 26 match ip dscp cs3 match ip dscp af31 class-map match-all vtraffic !--- Match voice bearer traffic for DSCP ef match ip dscp EF ! ! policy-map Voice class vtraffic priority 50 compress header ip rtp !--- Header compression class ctraffic bandwidth 8 class class-default fair-queue policy-map Shape class class-default shape average 243200 2432 0 service-policy Voice interface Serial2/1:0 no ip address ip pim sparse-dense-mode encapsulation frame-relay frame-relay intf-type dce ! interface Serial2/1:0.100 point-to-point ip address 192.168.10.1 255.255.255.0 ip pim sparse-dense-mode frame-relay class FRTStoRTP frame-relay interface-dlci 100 map-class frame-relay FRTStoRTP frame-relay fragment 320 service-policy output Shape !
! !--- Refer to the Network Infrastructure chapter in the SRND class-map match-any ctraffic !--- Match voice signaling for DSCP 24 and 26 match ip dscp cs3 match ip dscp af31 class-map match-all vtraffic !--- Match voice bearer traffic for DSCP ef match ip dscp EF policy-map Voice class vtraffic priority 50 compress header ip rtp !--- Header compression class ctraffic bandwidth 8 class class-default fair-queue policy-map Shape class class-default shape average 243200 2432 0 service-policy Voice map-class frame-relay FRTStoSJ frame-relay fragment 320 service-policy output Shape
Use these commands in order to verify your configuration:
RTP#show frame-relay fragment interface dlci frag-type size in-frag out-frag dropped-frag Se0/1:0.100 100 end-to-end 320 1209 0 0
RTP#show policy-map Policy Map Shape Class class-default Traffic Shaping Average Rate Traffic Shaping CIR 243200 (bps) Max. Buffers Limit 1000 (Packets) Bc 2432 Be 0 service-policy Voice Policy Map Voice Class vtraffic Strict Priority Bandwidth 50 (kbps) Burst 1250 (Bytes) compress: header ip rtp Class ctraffic Bandwidth 8 (kbps) Max Threshold 64 (packets) Class class-default Flow based Fair Queueing Bandwidth 0 (kbps) Max Threshold 64 (packets)
RTP#show policy-map interface Serial0/1:0.100: DLCI 100 - Service-policy output: Shape Class-map: class-default (match-any) 51000 packets, 3259829 bytes 5 minute offered rate 26000 bps, drop rate 0 bps Match: any Traffic Shaping Target/Average Byte Sustain Excess Interval Increment Rate Limit bits/int bits/int (ms) (bytes) 243200/243200 304 2432 0 10 304 Adapt Queue Packets Bytes Packets Bytes Shaping Active Depth Delayed Delayed Active - 0 51000 1613958 1 64 no Service-policy : Voice Class-map: vtraffic (match-all) 43343 packets, 2773952 bytes 5 minute offered rate 26000 bps, drop rate 0 bps Match: ip dscp ef (46) Queueing Strict Priority Output Queue: Conversation 40 Bandwidth 50 (kbps) Burst 1250 (Bytes) (pkts matched/bytes matched) 43474/1131487 (total drops/bytes drops) 0/0 compress: header ip rtp UDP/RTP (compression on, Cisco, RTP) Sent: 43474 total, 43448 compressed, 1650849 bytes saved, 957591 bytes sent 2.72 efficiency improvement factor 99% hit ratio, five minute miss rate 0 misses/sec, 1 max rate 17000 bps Class-map: ctraffic (match-any) 3767 packets, 202414 bytes 5 minute offered rate 0 bps, drop rate 0 bps Match: ip dscp cs3 (24) af31 (26) Queueing Output Queue: Conversation 41 Bandwidth 8 (kbps) Max Threshold 64 (packets) (pkts matched/bytes matched) 3768/202484 (depth/total drops/no-buffer drops) 0/0/0 Class-map: class-default (match-any) 3890 packets, 283463 bytes 5 minute offered rate 0 bps, drop rate 0 bps Match: any Queueing Flow Based Fair Queueing Maximum Number of Hashed Queues 32 (total queued/total drops/no-buffer drops) 0/0/0 RTP#
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