CUBE Transcoding on an MGX or VXSM WAN Switch

CUBE (SBC) transcoding can be done using the DSP farm on an MGX or VXSM WAN switch as a transcoder via the H.248 protocol.

Transcoding is the process of translating one type of media stream or codec into another type of media stream or codec. For example, PCMU into G.726-32.

Transcoding is triggered by a response from the callee endpoint, indicating that none of the codecs in the initial request are acceptable. Responses that trigger transcoding are as follows:

•415 - Unsupported media type (SIP)

•488 - Not acceptable here (SIP)

•65 - Bearer Capability not implemented disconnect cause value (H.323)

When transcoding is triggered, the SBE places a transcoder in the media path between the incoming and outgoing DBEs. The SBE then sends a new request to the callee, with a new codec type generated by the transcoder. The SBE may have to iterate through the list of codecs until it finds one that the callee accepts. Once a codec is found that is accepted by the callee, the call is connected and media transmission begins.

This example shows how to configure CUBE Transcoding on an MGX or VXSM WAN switch. Each segment of the example is explained below.

SBC SBE Configuration

Configures the SBC and SBE.

Media Gateway Configuration

Configures an MGX WAN switch as the media gateway as follows:

•media-gateway - Configures the IP address of the MGX WAN switch media gateway.

•codecs - Configures the codecs supported by the media gateway.

•transcoder - Configures this media gateway as a transcoder.

•control address h248 index - Configures the IPv4, H.248 control address of this transcoder.

•transport udp - Configures UDP as the transport for the H.248 signaling.

•ipv4 - Configures the IP address of the SBC.

Adjacency Configuration

Configures the Nav_A and Nav_B adjacencies.

Call Policy: Adjacency Connection

Establishes the connection between the Nav_A and Nav_B adjacencies.

CAC Table: Codec Enforcement

(Optional) Enforces which codecs each side of the call is allowed to use.

Transcoding CUBE on the MGX (in Segments)

SBC Configuration 

sbc My_SBC 

  sbe

MGX as Media Gateway Configuration 

media-gateway ipv4 10.0.181.2 

	codecs m=audio 1234 RTP/AVP 0 8,a=rtpmap:0 PCMU/8000,a=rtpmap:8 PCMA/8000 

	transcoder 

	control address h248 index 1 

	transport udp 

	ipv4 23.30.1.1 - SBC ip address 

 
   
 
    
   
 Adjacency 1 Configuration 
 
    
   
 
    
   adjacency sip Nav_A 

 
   
 
    
   
 
    
    inherit profile preset-access 

 
   
 
    
   
 
    
    preferred-transport udp 

 
   
 
    
   
 
    
    signaling-address ipv4 23.30.1.1 

 
   
 
    
   
 
    
    statistics method summary 

 
   
 
    
   
 
    
    signaling-port 5060 

 
   
 
    
   
 
    
    remote-address ipv4 23.31.0.0 255.255.0.0 

 
   
 
    
   
 
    
    signaling-peer 23.31.1.2 

 
   
 
    
   
 
    
    attach 

 
   
 
    
   
 
    
 
   
 
    
   
 Adjacency 2 Configuration 
 
    
   
 
    
adjacency sip Nav_B

 
   
 
    
   
 
    
    nat force-off

 
   
 
    
   
 
    
    preferred-transport udp

 
   
 
    
   
 
    
    signaling-address ipv4 23.30.1.1

 
   
 
    
   
 
    
    statistics method summary

 
   
 
    
   
 
    
    signaling-port 5060

 
   
 
    
   
 
    
    remote-address ipv4 23.32.0.0 255.255.0.0

 
   
 
    
   
 
    
    signaling-peer 23.32.1.2

 
   
 
    
   
 
    
    account Nav_B

 
   
 
    
   
 
    
    attach

 
   
 
    
   
 
    
 
   
 
    
   
 Call Policy: Adjacency Connection 
 
    
   
 
    
  call-policy-set 1

 
   
 
    
   
 
    
    first-call-routing-table ROUTE-ON-DEST-NUMB

 
   
 
    
   
 
    
    rtg-dst-address-table ROUTE-ON-DEST-NUMB

 
   
 
    
   
 
    
     entry 1

 
   
 
    
   
 
    
      action complete

 
   
 
    
   
 
    
      dst-adjacency Nav_A

 
   
 
    
   
 
    
      match-address 91939 digits

 
   
 
    
   
 
    
      prefix

 
   
 
    
   
 
    
     entry 2

 
   
 
    
   
 
    
      action complete

 
   
 
    
   
 
    
      dst-adjacency Nav_B

 
   
 
    
   
 
    
      match-address 40852 digits

 
   
 
    
   
 
    
      prefix

 
   
 
    
   
 
    
    complete

 
   
 
    
   
 
    
  call-policy-set default 1

 
   
 
    
   
 
    
  media-address ipv4 23.30.1.10

 
   
 
    
   
 
    
  port-range 10000 64000 any

 
   
 
    
   
 
    
  activate

 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
    
   
 CAC Policy: Codec Enforcement 
 
    
   
 
    
cac-policy-set 1

 
   
 
    
   
 
    
    first-cac-table Transcode

 
   
 
    
   
 
    
    first-cac-scope dst-adjacency

 
   
 
    
   
 
    
    cac-table Transcode

 
   
 
    
   
 
    
     table-type policy-set

 
   
 
    
   
 
    
     entry 1

 
   
 
    
   
 
    
      cac-scope call

 
   
 
    
   
 
    
      caller-codec-list sideA

 
   
 
    
   
 
    
      callee-codec-list sideB

 
   
 
    
   
 
    
      action cac-complete

 
   
 
    
   
 
    
    complete

 
   
 
    
   
 
    
   cac-policy-set global 1

 
   
 
    
   
 
    
<...>

 
   
 
    
   
 
    
   codec list sideA

 
   
 
    
   
 
    
    codec PCMA

 
   
 
    
   
 
    
   codec list sideB

 
   
 
    
   
 
    
    codec G729

 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
     
    
   
 Transcoding CUBE on the MGX (for Copy and Paste) 
 
    
   
 
    
sbc My_SBC 

 
   
 
    
   
 
    
  sbe

 
   
 
    
   
 
    
 
   
 
    
   
 
    
media-gateway ipv4 10.0.181.2 

 
   
 
    
   
 
    
	codecs m=audio 1234 RTP/AVP 0 8,a=rtpmap:0 PCMU/8000,a=rtpmap:8 PCMA/8000 

 
   
 
    
   
 
    
	transcoder

 
   
 
    
   
 
    
	control address h248 index 1

 
   
 
    
   
 
    
	transport udp

 
   
 
    
   
 
    
	ipv4 23.30.1.1 - SBC ip address

 
   
 
    
   
 
    
 
   
 
    
   
 
    
adjacency sip Nav_A

 
   
 
    
   
 
    
    inherit profile preset-access

 
   
 
    
   
 
    
    preferred-transport udp

 
   
 
    
   
 
    
    signaling-address ipv4 23.30.1.1

 
   
 
    
   
 
    
    statistics method summary

 
   
 
    
   
 
    
    signaling-port 5060

 
   
 
    
   
 
    
    remote-address ipv4 23.31.0.0 255.255.0.0

 
   
 
    
   
 
    
    signaling-peer 23.31.1.2

 
   
 
    
   
 
    
    attach

 
   
 
    
   
 
    
 
   
 
    
   
 
    
adjacency sip Nav_B

 
   
 
    
   
 
    
    nat force-off

 
   
 
    
   
 
    
    preferred-transport udp

 
   
 
    
   
 
    
    signaling-address ipv4 23.30.1.1

 
   
 
    
   
 
    
    statistics method summary

 
   
 
    
   
 
    
    signaling-port 5060

 
   
 
    
   
 
    
    remote-address ipv4 23.32.0.0 255.255.0.0

 
   
 
    
   
 
    
    signaling-peer 23.32.1.2

 
   
 
    
   
 
    
    account Nav_B

 
   
 
    
   
 
    
    attach

 
   
 
    
   
 
    
 
   
 
    
   
 
    
call-policy-set 1

 
   
 
    
   
 
    
	first-call-routing-table ROUTE-ON-DEST-NUMB

 
   
 
    
   
 
    
	rtg-dst-address-table ROUTE-ON-DEST-NUMB

 
   
 
    
   
 
    
	entry 1

 
   
 
    
   
 
    
		action complete

 
   
 
    
   
 
    
		dst-adjacency Nav_A

 
   
 
    
   
 
    
		match-address 91939 digits

 
   
 
    
   
 
    
		prefix

 
   
 
    
   
 
    
	entry 2

 
   
 
    
   
 
    
		action complete

 
   
 
    
   
 
    
		dst-adjacency Nav_B

 
   
 
    
   
 
    
		match-address 40852 digits

 
   
 
    
   
 
    
		prefix

 
   
 
    
   
 
    
	complete

 
   
 
    
   
 
    
	call-policy-set default 1

 
   
 
    
   
 
    
	media-address ipv4 23.30.1.10

 
   
 
    
   
 
    
	port-range 10000 64000 any

 
   
 
    
   
 
    
	activate

 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
    
   
 
    
cac-policy-set 1

 
   
 
    
   
 
    
	first-cac-table Transcode

 
   
 
    
   
 
    
	first-cac-scope dst-adjacency

 
   
 
    
   
 
    
	cac-table Transcode

 
   
 
    
   
 
    
	table-type policy-set

 
   
 
    
   
 
    
	entry 1

 
   
 
    
   
 
    
		cac-scope call

 
   
 
    
   
 
    
		caller-codec-list sideA

 
   
 
    
   
 
    
		callee-codec-list sideB

 
   
 
    
   
 
    
		action cac-complete

 
   
 
    
   
 
    
	complete

 
   
 
    
   
 
    
	cac-policy-set global 1

 
   
 
    
   
 
    
	codec list sideA

 
   
 
    
   
 
    
		codec PCMA

 
   
 
    
   
 
    
		codec list sideB

 
   
 
    
   
 
    
		codec G729

 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
     
    
   
 Transcoding CUBE on the MGX (with CLI Prompts) 
 
    
   
 
    
Router# config t

 
   
 
    
   
 
    
Router(config)# sbc My_SBC 

 
   
 
    
   
 
    
Router(config-sbc)# sbe

 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
    
   
 
    
PE25_ASR-1004(config-sbc-sbe)# media-gateway ipv4 10.0.181.2

 
   
 
    
   
 
    
PE25_ASR-1004(config-sbc-sbe-mg)# codecs m=audio 1234 RTP/AVP 0 8,a=rtpmap:0 
PCMU/8000,a=rtpmap:8 PCMA/8000

 
   
 
    
   
 
    
PE25_ASR-1004(config-sbc-sbe-mg-codecs)# transcoder

 
   
 
    
   
 
    
PE25_ASR-1004(config-sbc-sbe-mg-codecs)# control address h248 index 1

 
   
 
    
   
 
    
PE25_ASR-1004(config-sbc-sbe-ctrl-h248)# transport udp

 
   
 
    
   
 
    
PE25_ASR-1004(config-sbc-sbe-ctrl-h248)# ipv4 23.30.1.1

 
   
 
    
   
 
    
PE25_ASR-1004(config-sbc-sbe-ctrl-h248)# exit 

 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
    
   
 
    
Router(config-sbc-sbe)# adjacency sip Nav_A

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# inherit profile preset-access

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# preferred-transport udp

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# signaling-address ipv4 23.30.1.1

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# statistics method summary

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# signaling-port 5060

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# remote-address ipv4 23.31.0.0 255.255.0.0

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# signaling-peer 23.31.1.2

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# attach

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Router(config-sbc-sbe)# adjacency sip Nav_B

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# nat force-off

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# preferred-transport udp

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# signaling-address ipv4 23.30.1.1

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# statistics method summary

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# signaling-port 5060

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# remote-address ipv4 23.32.0.0 255.255.0.0

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# signaling-peer 23.32.1.2

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# account Nav_B

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# attach

 
   
 
    
   
 
    
Router(config-sbc-sbe-adj-sip)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
Router(config-sbc-sbe)# call-policy-set 1

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy)# first-call-routing-table ROUTE-ON-DEST-NUMB

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy)# rtg-dst-address-table ROUTE-ON-DEST-NUMB

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy)#entry 1

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# action complete

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# dst-adjacency Nav_A

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# match-address 91939 digits

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# prefix

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# entry 2

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# action complete

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# dst-adjacency Nav_B

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# match-address 40852 digits

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# prefix

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# complete

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# call-policy-set default 1

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# media-address ipv4 23.30.1.10

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# port-range 10000 64000 any

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# activate

 
   
 
    
   
 
    
Router(config-sbc-sbe-rtgpolicy-rtgtable-entry)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
    
   
 
    
Router(config-sbc-sbe)# cac-policy-set 1

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy)# first-cac-table Transcode

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy)# first-cac-scope dst-adjacency

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy)# cac-table Transcode

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy-cactable)# table-type policy-set

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy-cactable)# entry 1

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy-cactable-entry)# cac-scope call

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy-cactable-entry)# caller-codec-list sideA

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy-cactable-entry)# callee-codec-list sideB

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy-cactable-entry)# action cac-complete

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy-cactable-entry)# complete

 
   
 
    
   
 
    
Router(config-sbc-sbe-cacpolicy-cactable-entry)# cac-policy-set global 1 

 
   
 
    
   
 
    
Router(config-sbc-sbe)# codec list sideA

 
   
 
    
   
 
    
Router(config-sbc-sbe-codec-list)# codec PCMA

 
   
 
    
   
 
    
Router(config-sbc-sbe-codec-list)# codec list sideB

 
   
 
    
   
 
    
Router(config-sbc-sbe-codec-list)# codec G729

 
   
 
    
   
 
    
Router(config-sbc-sbe-codec-list)# exit

 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
    
   
 
    
 
   
 
     
    
   
 Verify Media Gateway Associations 
 
    
    
   
 
    
Router# show sbc My_SBC sbe media-gateway-associations

 
   
 
    
   
 
    
 
   
 
    
   
 
    
SBC Service "My_SBC"

 
   
 
    
   
 
    
  Media gateway 10.0.181.2:2951

 
   
 
    
   
 
    
    Gateway Protocol   = megaco

 
   
 
    
   
 
    
    Transport Protocol = UDP^M

 
   
 
    
   
 
    
    Local Address      =23.30.1.1:2944

 
   
 
    
   
 
    
 
   
 
    
   
 
    
                Sent            Received        Failed          Retried

 
   
 
    
   
 
    
    Requests            55               2               0               0

 
   
 
    
   
 
    
    Replies              2              55      -                        0