It’s something I didn’t do in many many years, that’s why I create this post. Just for me to find all the information for the next time when I will have to configure MGCP.
MGCP Verbs :
| Command | Message Name | Sent By | Description |
|---|---|---|---|
| AUEP | AuditEndpoint | CallManager | Get the status of a given endpoint. |
| AUCX | AuditConnection | CallManager | Retrieves all the parameters associated with a connection. |
| CRCX | CreateConnection | CallManager | Creates a connection between two endpoints. |
| DLCX | DeleteConnection | Both | From CallManager:Terminates a current connection. From Gateway:Indicates that a connection can no longer be sustained. |
| MDCX | ModifyConnection | CallManager | Changes the parameters (Update info) associated with an established connection. |
| RQNT | NotificationRequest | CallManager | Instructs the gateway to watch for special events such as hooks or DTMF tones. It is also used to instruct the gateway to provide a signal to the endpoint (for example, dial tone and busy tone). |
| NTFY | Notify | Gateway | Informs the Cisco CallManager when requested events occur. |
| RSIP | RestartInProgress | Gateway | Informs the Cisco CallManager that an endpoint or group of endpoints are taken out or placed back into service. |
| EPCF | Endpoint configuration | Callmanager | Alert configuration of the endpoint(things like gain level, codec, etc |
Key Parameters :
X: Request id, RQNT/NTFY correlator
C: Callid, String
N: Notified entity (addr of call agent to be notified)
I: Connection id
S: Signal request(dialtone, ringback etc)
M : Connection mode (sendonly, recvonly, sendrecv)
T: Events to be detected (on/off hook, DTMF)
O: Events detected
R: Events requested
D: Digit map
B: Bearer Information (A-law, mu-law)
Here is a call between a SIP device and the FXS phone. The picture above is pretty correct. 😉
VG200 FXS (7777) calls SIP (1002)
Red is VG200, Blue is CUCM
NTFY 100785530 aaln/S0/0@VG202.homemade.nl MGCP 0.1 N: ca@192.168.5.2:2427 X: 52 O: L/hd
200 100785530 RQNT 100 AALN/S0/0@VG202.homemade.nl MGCP 0.1 X: 53 R: L/hu, D/[0-9ABCD*#] S: L/dl Q: process,loop
200 100 OK
NTFY 100785531 aaln/S0/0@VG202.homemade.nl MGCP 0.1
N: ca@192.168.5.2:2427
X: 53
O: D/1
200 100785531
RQNT 101 AALN/S0/0@VG202.homemade.nl MGCP 0.1
X: 54
R: L/hu, D/[0-9ABCD*#], L/hf
S:
Q: process,loop
200 101 OK
NTFY 100785532 aaln/S0/0@VG202.homemade.nl MGCP 0.1
N: ca@192.168.5.2:2427
X: 54
O: D/0
200 100785532
NTFY 100785533 aaln/S0/0@VG202.homemade.nl MGCP 0.1
N: ca@192.168.5.2:2427
X: 54
O: D/0
200 100785533
NTFY 100785534 aaln/S0/0@VG202.homemade.nl MGCP 0.1
N: ca@192.168.5.2:2427
X: 54
O: D/2
200 100785534
CRCX 102 AALN/S0/0@VG202.homemade.nl MGCP 0.1
C: A000000001a005ac000000F5
X: 55
L: p:20, a:PCMU, s:off, t:b8, fxr/fx:t38
M: recvonly
R: L/hu
Q: process,loop
200 102 OK
I: F
v=0
c=IN IP4 192.168.5.6
m=audio 19314 RTP/AVP 0 100
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194,200-202
a=X-sqn:0
a=X-cap: 1 audio RTP/AVP 100
a=X-cpar: a=rtpmap:100 X-NSE/8000
a=X-cpar: a=fmtp:100 192-194,200-202
a=X-cap: 2 image udptl t38
RQNT 103 AALN/S0/0@VG202.homemade.nl MGCP 0.1
X: 56
R: L/hu
S: G/rt
Q: process,loop
200 103 OK
MDCX 104 AALN/S0/0@VG202.homemade.nl MGCP 0.1
C: A000000001a005ac000000F5
I: F
X: 57
L: p:20, a:PCMU, s:off, t:b8, fxr/fx:t38
M: sendrecv
R: L/hu, L/hf, D/[0-9ABCD*#], FXR/t38
S:
Q: process,loop
v=0
o=- 15 0 IN EPN AALN/S0/0@VG202.homemade.nl
s=Cisco SDP 0
t=0 0
m=audio 29092 RTP/AVP 0
c=IN IP4 192.168.5.117
a=X-sqn:0
a=X-cap:1 image udptl t38
200 104 OK
RQNT 105 AALN/S0/0@VG202.homemade.nl MGCP 0.1
X: 58
R: L/hu, D/[0-9ABCD*#], L/hf, FXR/t38
S:
Q: process,loop
200 105 OK
MDCX 106 AALN/S0/0@VG202.homemade.nl MGCP 0.1
C: A000000001a005ac000000F5
I: F
X: 59
M: recvonly
R: L/hu
Q: process,loop
200 106 OK
DLCX 107 AALN/S0/0@VG202.homemade.nl MGCP 0.1
C: A000000001a005ac000000F5
I: F
X: 5a
R: L/hu
S:
Q: process,loop
250 107 OK
P: PS=381, OS=60960, PR=377, OR=60320, PL=0, JI=7, LA=1
NTFY 100785535 aaln/S0/0@VG202.homemade.nl MGCP 0.1
N: ca@192.168.5.2:2427
X: 5a
O: L/hu
200 100785535 RQNT 108 AALN/S0/0@VG202.homemade.nl MGCP 0.1 X: 5b R: L/hd S: Q: process,loop 200 108 OK
More information :Â http://www.cisco.com/c/en/us/support/docs/voice/media-gateway-control-protocol-mgcp/44130-understanding-mgcp.html
For debugging and decoding the messages :Â http://www.cisco.com/c/en/us/support/docs/voice-unified-communications/unified-communications-manager-callmanager/42104-debug-mgcp.html
http://docwiki.cisco.com/wiki/Cisco_IOS_Voice_Troubleshooting_and_Monitoring_–_MGCP_Overview#Figure:_MGCP_Call_Flow_Topology
