Cisco Cisco TelePresence Video Communication Server Expressway

H.323 call with a non-registered endpoint with public IP

VCS Expressway

source port

Internet endpoint

server (listening) port

VCS Expressway

server (listening) port

Internet endpoint

source port

Call direction

Outbound to an endpoint in the Internet

Inbound from an endpoint in the Internet

Open firewall

DMZ to Internet

Internet to DMZ

IP address

IP address of

VCS Expressway

Any IP address

IP address of

VCS Expressway

Any IP address

IP Po

Initial RAS
connection

Q 931 / H.225
signaling

TCP P

15000 to 19999

TCP G

1720

TCP M

1720

TCP K

1720

H.245

TCP P

15000 to 19999

TCP H

>= 1024

TCP P

15000 to 19999

TCP H

>= 1024

RTP

UDP Y

50000 to 54999

UDP E

>= 1024

UDP Y

50000 to 54999

UDP E

>= 1024

RTCP

UDP Y

50000 to 54999

UDP E

>= 1024

UDP Y

50000 to 54999

UDP E

>=1024

public

Internet

P = Protocols > H.323 > Gatekeeper > Call

signaling port range start to end: default =
15000 to 19999

G = Endpoint signaling port, specified by

a) IP Port in call request
b) DNS lookup for URI to call
c) 1720 if IP address but no port specified
Can be: any port >= 1024, typically 1720

M = Protocols > H.323 Call signaling TCP port:

default = 1720

K = Endpoint signaling port: any port >= 1024,

typically 1720

H = Endpoint H.245 signaling port:

= any IP port >= 1024
= 15000 to 19999 to another VCS
= 5555 to 5574 for MXP static setting
= 11000 to 65000 for MXP dynamic setting

= Local Zone > Traversal Subzone >

Traversal Media port start to end
(configured on VCS Expressway): default =
50000 to 54999

E = Endpoint media port range; value used is

specified in codec negotiations:
= any IP port above 1024
= 50000 to 54999 for another VCS
= 2326 to 2385 for MXP static setting
= 11000 to 65000 for MXP dynamic setting

VCS Control

VCS Expressway

DMZ