IIUC Notes – Voice Ports and Dial Peers


More of my IIUC study notes.  As always, feel free to correct.  I really need to have a real post, don't I?

show voice port summary

  • Shows the voice ports available for use

  • An ephone-dn shows up as efxs, so all these are ephone-dns.
  • Channels are numbered 0-23; timeslots are numbered 1-24

FXS Ports

  • Connect to end stations like analog phones and fax machines
  • Signaling
    • Ground start: New connections started by grounding wires
      • Typically used when tied to PBXes
    • Loop start:  New connections started by sending DC voltage
      • Default
      • Typically used when connecting to analog devices
  • Call progress tones
    • Audible tones to let the user know the status of a call
      • Dial tone, busy, call waiting, etc.
      • Different in each geographical area
  • Caller ID
    • Identifies the name and number that calls on this line should appear

R1(config)#voice-port 0/0/0
R1(config-voiceport)#signal loopStart <- Use loopstart signaling
R1(config-voiceport)#cptone PE <- Uses CP tones from Peru
R1(config-voiceport)#station-id name Corporate Fax
R1(config-voiceport)#station-id number 5551212

FXO Ports

  • Connects to CO or PBX
  • A lot of the same configurations as FXS ports
  • Two additional to discuss
    • dialt-type:  DTMF or pulse dialing
    • ring:  The number of rings to wait before answering; usually 1
      • Think of allowing a home user to answer the phone before the fax machine picks up

R1(config)#voice-port Reverse Phone 0/0/1
R1(config-voiceport)#dial-type dtmf <- touch tone
R1(config-voiceport)#ring 3 <- wait 3 rings before answering

Digital Voice Ports

  • Unlike analog voice ports, digital voice ports must be configured to function with the network to which they are attached.
  • Voice and WAN interface cards (VWICs) provide digital voice port
  • show controllers t1
  • Framing:  defines how to format the frames
    • SF or ESF
  • Line coding:  encodes the signal in a way to maintain sychronization
    • AMI or B8ZS
  • Clock source:  defines who dictates the clocking
  • Signaling:  channel signaling
    • CAS:  use ds0-group
      • Ports show up as 0/0:1, where 0/0 is the physical port and 1 is the ds0 group
    • CCS:  use pri-group
      • Ports shows up as 0/0:23, where 0/0 is the physical port and 23 is the signaling channel (16 in E1)

R1(config)#isdn switch-type primary-5ess <- If using CCS
R1(config)#controller t1 0/0
R1(config-controller)#framing esf
R1(config-controller)#linecode b8zs
R1(config-controller)#clock source line <- get clocking from provider
For CAS:
R1(config-controller)#ds0-group 1 timeslots 1-24 type fxo-loop-start <- Using FXO loopstart signaling
For CCS:
R1(config-controller)#pri-group 1 timeslots 1-24 <- assumes signaling from CCS and ISDN switch-type

Dial Peers

  • "Routing" for phone numbers
  • Tells a voice gateway where to send calls based on dialed number
  • Two types dial peers
    • POTS:  Traditional connections like T1 and analog phone lines
    • VOIP:  Connections to an IP address
  • show dial-peer voice summary

R1(config)#dial-peer voice 1101 pots
R1(config-dial-peer)#destination-pattern 1101  <- This number…
R1(config-dial-peer)#port 0/0/0  <-  …is on this FXS port.

R1(config)#dial-peer voice 1102 pots
R1(config-dial-peer)#destination-pattern 1102  <- This number…
R1(config-dial-peer)#port 1/0:23  <-  …is on this T1 PRI port.

R1(config)#dial-peer voice 1103 voip
R1(config-dial-peer)#destination-pattern 1103  <- This number…
R1(config-dial-peer)#session target ipv4:  <- …is at this IP address…
R1(config-dial-peer)#codec g711ulaw  <- …and use this codec when you get there.

Aaron Conaway

I shake my head around sometimes and see what falls out. That's what lands on these pages. If you have any questions, the best way to contact me is through Twitter at @aconaway.

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