Port Change every calls from cucm to avaya

[remantapiiii84072]

Hi all,

i have some anomali, when i make a call from CUCM to Avaya systems, the port always change.

first we see the call using port 9390, the other call using port 9394, then change using another port.

anyone why this happened?

thanks

RT

[Roger Kallberg]

Are you referring to the port used for the RTP stream? If so that intended as it use a port from a defined range dynamically.

[remantapiiii84072]

Hi Roger,

thanks for replied,

i just used for voice audio only. the problem is from security engineer not allow for us to open it range port.

can you tell the reason why the port always change?

thanks

rt

[Roger Kallberg]

That's how RTP works, it uses a defined range of ports. How are you connecting the two systems together? Do you have a SBC between them?

[remantapiiii84072]

Hi Roger,

oh i see that, do you have document for it?

i use sip trunk to Cube VG.

thanks

RT

[Roger Kallberg]

Configuration guide for Cube. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/configuration/cube-book.html

[Nithin Eluvathingal]

RTP port range for CUCM is from 16384 - 32767 and asper the tcp/udp port usage guide I don't see any port 9390 or 9394 mentioned.

You can refer the below guide and  make sure that you allow the ports based on the  trunk you configured.The below guide is for 10.x use guide for your version. 

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/port/10_5_x/cucm_b_port-usage-cucm-105x/cucm_b_port-usage-cucm-105x_chapter_00.html 

I will recommend to use any any policy between the voice network.:)

[Roger Kallberg]

Pure speculation, but it could be that there is a SBC in-between the systems and that it runs on a 4K gateway. Those have a much larger span of ports, from 8000 to 48198 I think.

[remantapiiii84072]

Hi Roger,

do you have documentation guide about this?

thanks

AD

[Roger Kallberg]

Other than what @Nithin Eluvathingal already shared documentation for what?

[remantapiiii84072]

Hi Nithin,

thanks for replied,

i dont see it neither, maybe i must ask the avaya experts since the problem happen in their avaya telephony systems.

thanks for documentation and recommendation.

thanks

RT

[Nithin Eluvathingal]

RTP ports are  random and its in range and that's how it works. I feel like from AVAYA side it could be a H323 trunk to SBC, because your port 9030 and 9034 falls under H323.

Your security guy has to open the ports in range for voice and there is no alternative. 

I found a link for Avaya port usage, not sure if this document is related to your version or not.

https://downloads.avaya.com/css/P8/documents/101057187

IP Ports and Protocols used by H.323 Devices

This Port	Type	Description
389	statique - TCP	ILS Registration  (LDAP)
1503	statique - TCP	T120
1718	statique - TCP	Gatekeeper Discovery
1719	statique - UDP	Gatekeeper RAS
1720	statique - TCP	H323 Call Setup
1731	statique - TCP	Audio Call Control
1024-65535	Dynamique - TCP	H245 Call parameters
1024-65535	Dynamique - UDP	RTP (Video Data Streams)
1024-65535	Dynamique - UDP	RTP (Audio Data Streams)
1024-65535	Dynamique - UDP	RTCP (Control Information)