Table of Contents
Advertisement
Session Refresher
SIP T1 (msec)
SIP T2 (msec)
SIP T4 (msec)
Invite Linger Timer
General Linger Timer
Cancel General No
Response Time (msec)
connected SIP proxy is required to support compact form.
Who will send dialog to keep alive message (re-invite or
update).
UAC: User Agent Client will do the refresh (default setting)
UAS: User Agent Server will do the refresh
T1 determines several timers as defined in RFC3261. For
example, when an unreliable transport protocol is used, a Client
Invite transaction retransmits requests at an interval that start at
T1 seconds and doubles after every retransmission. A Client
General transaction retransmits requests at an interval that
starts at T1 and doubles until it reaches T2. (Default Value:
500ms) **
Determines the maximum retransmission interval as defined in
RFC3261. For example, when an unreliable transport protocol
is used, general requests are retransmitted at an interval which
starts at T1 and doubles until reaches T2. If a provisional
response is received, retransmission continue but at an interval
of T2. (Default Value: 4000ms) **
T4 represents the amount of time the network takes to clear
message between client and server transactions as defined in
RFC3261. For example, when it works with an unreliable
transport protocol, T4 determines the time that UAS waits after
receiving an ACK message and before terminating the
transaction. (Default Value: 5000ms) **
After sending an ACK for an INVITE final response, a client
cannot be sure that the server has received the ACK message.
The client should be able to retransmit the ACK upon receiving
retransmissions of the final response for this timer. This timer is
also used when a 222 response is sent for an incoming Invite.
In this case, the ACK is not part of the Invite transaction.
After a UAS sends a final response, the UAS cannot be sure
that the client has received the response message. The UAS
should be able to retransmit the response upon receiving
retransmissions of the request based on this timer.
When sending a CANCEL request on a General transaction,
the User Agent waits for cancel General No Response Timer
milliseconds before timeout termination if there is no response
45
Internet Telephony Gateway
VGW-400 Series
Advertisement
Table of Contents
