Enabling Application-Level Gateways For Applications; With Special Needs; Enabling Sip Services - HP 7102dl - ProCurve Secure Router Configuration Manual

Setting Up Quality of Service
Example: Configuring QoS for VoIP
N o t e s
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Enabling Application-Level Gateways for Applications

with Special Needs

G.711 is an H.323 application, which handles VoIP traffic. The application may
cause the VoIP traffic to behave in a different manner than data traffic. For
example, it sends VoIP traffic on one port and receives it on another port. If
you have enabled the Secure Router OS firewall, you must also enable the
H.323 application-level gateway (ALG) so that the firewall will automatically
permit return traffic. The ALG will also prevent the firewall from discarding
VoIP traffic for exhibiting unusual behavior.
The H.323 ALG is disabled by default. Enter:
ProCurve(config)# ip firewall alg h323
If your VoIP application uses SIP, then you should determine to which port or
ports the application sends traffic. The default port enabled for SIP on the
ProCurve Secure Router is UDP port 5060. If your application uses a different
port than you should open it with this command:
Syntax: ip firewall alg sip udp <port number>
If your RPT application uses unexpected ports, then the firewall may drop
return traffic. You should enable firewall traversal to allow all packets that are
part of an RTP session to pass through the firewall:
ProCurve(config)# ip rtp firewall-traversal
See Chapter 4: ProCurve Secure Router OS Firewall—Protecting the Inter-
nal, Trusted Network for more information on ALGs and firewall traversal.

Enabling SIP Services

The VoIP application in this example uses H.323. However, if users in your
network use SIP applications, then your router may need to act as a SIP proxy
and registrar server.
SIP is a peer-to-peer protocol that initiates, regulates, and terminates sessions
that carry VoIP, instant messages, video streams, or other RTP packets
between two users. SIP was designed to provide VoIP calls with many of the
features associated with traditional telephone calls, such as dialing a number
or receiving a busy signal.