Polycom V2IU 5300-S User Manual page 69

Field
SIP Server Address
SIP Server Port
Always hairpin SIP media
SIP Expires override
SIP Soft-Switch Expires override
Description
The SIP server provides
session-initialization protocol service to IP
phones, client adapters and gateways.
If a SIP ALG is needed, enter the address
(either an IP or URL) for the SIP Server.
This address should be reached via the
Provider side Ethernet port.
If a SIP ALG is needed, enter a port for the
SIP Server Port.
Normally set to False. If set to True, then
SIP phone-to-phone calls made on the
Subscriber side of the 5300-S will always
have their RTP traffic flow to and back
from the EP subscriber interface.
The SIP Expires override field specifies
the number of seconds a registration
should be valid. The 5300-S uses this
value to re-write the expires value
returned from the soft-switch before
forwarding it to the IP phone. This value is
used to force the IP phone to register at
the configured interval And helps to
maintain NAT bindings in network based
firewalls when the 5300-S is performing
NAT/firewall traversal.
The SIP Soft-Switch expires override field
specifies the number of seconds that
should be used when forwarding
registration messages to the soft-switch
on behalf of the IP phones. This should be
higher than the rate pacing value,
otherwise, the soft-switch may consider
the phone's registration to have expired. If
this field is not set, the phone's value is
forwarded unchanged.
Configuring VoIP
5 - 3