Cisco VoiP (Voice over IP)

Call Manager Debug

On Router MGCP controlled
- #sh rtp statistics

Cisco phones

7911

Configures for sccp. (Not using SIP yet)
Boot process
1. DHCP gives phone ip, and option 150 gives it the CM ip's.
2. Phone tftp's to CM option 150 ip to retrieve config file SEP.cnf.xml
  - From wireshark trace,
    1. CTLSEP001F9EABA0F3.tlv (File not found on CM) and then
    2. SEP001F9EABA0F3.cnf.xml (See phone mac ?) (includes, CM ip and code to load e.g. SCCP11.8-5-2S )
    3. English_United_States/tc-sccp.jar
    4. United_States/g3-tones.xml
    5. sccp login on tcp port 2000 to ip from config above.

CCMX Notes

Cisco Unified CCX. Cisco Unified CCX Premium.
- QM and AQM are available only with Cisco Unified CCX Premium.
Note: Voice monitoring and recording are supported only on IPCC Express Enhanced and Premium Edition, not on Standard Edition.
The VoIP silent monitoring server must be on the same VLAN as the agent phones and requires an available SPAN port.
Cisco VoIP call recording with CallRex Call Recording™ software can be achieved through either packet-sniffing via port mirroring or with forked audio using the Built-in Bridge in selected Cisco IP-based telephones.
Call recording can be achieved using the Built-in Bridge (BIB) option on selected Cisco IP phones.
- http://www.cisco.com/en/US/docs/voice_ip_comm/uc_system/UC6.0.1/features_apps/CMmonrec.html

Cisco BW calculations, and optimization. http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080094ae2.shtml#configvoice
- Packet size, VAD
VoiP Bandwidth savings.
1. Codec: G.711 (64 Kbps) , G.729 (8 Kbps - Voice)(24 Kbps - with serial overhead) (32kbps - on ethernet)
2. Changing Voice Payload Sizes
  - G.729 call with voice payload size of 20 bytes (20 ms):= 24 Kbps 40 bytes (40 ms):= 16 Kbps
    - Note: L2 headers are not considered in this calculation.
3. RTP Header-Compression or Compressed RTP (cRTP)
  - Compressed Real-Time Protocol (cRTP) reduces the IP/UDP/RTP headers to 2or 4bytes (cRTP is not available over Ethernet).
Call Admission Control
- Locations, for systems with centralized call processing. Bandwidth (kbps)
- Regions define the type of compression (G.711, G.723, or G.729) that is used on the link, and locations define the amount of available bandwidth for the link.
- You assign each device in the system to both a region (by means of a device pool) and a location.

DSP

check DSP Keepalive status in Cisco Voice gateways.
- Voice-GW#test voice driver
- # sh voice dsp
- # show call resource voice stats
  - If above gives 0, you have not enabled dsp services dspfarm under the voice-card

Setup BRI at remote site for breakout using central callmanager, H.323

      !
      voice-card 0
        dspfarm
        dsp services dspfarm
      !
      voice call carrier capacity active
      voice rtp send-recv
      !
      voice service voip 
        h323
      !
      interface FastEthernet0/0.x
        description VOICE-Vlan
        ip address XX
        h323-gateway voip interface
        h323-gateway voip bind srcaddr XX
      !
      interface BRI1/0
        description ISDN-VoicePort
        no ip address
        isdn switch-type basic-net3
        isdn point-to-point-setup
        isdn incoming-voice voice
        isdn send-alerting
        isdn sending-complete
      !
      voice-port 1/0
        compand-type a-law
      !
      voice-port 1/1
        compand-type a-law
      !
      !
      dial-peer voice 20 voip
        destination-pattern 01132699..
        voice-class codec 1
        session target ipv4:10.110.0.102
        incoming called-number 01132699..
        dtmf-relay h245-alphanumeric
        no vad
      !
      dial-peer voice 3 pots
        destination-pattern .T
        progress_ind alert enable 8
        incoming called-number 9...
        direct-inward-dial
        port 0/1
        forward-digits all
     !

...

CategoryCisco

Cisco VoiP (Voice over IP)

Call Manager Debug

Cisco phones

7911

CCMX Notes

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DSP