Proxies can remove any state for the call. Both UAs are supposed to send a BYE, and call stateful Not received before the interval passes, the session is considered The interval for the session refresh requests is determined through a (referred to as session refresh requests) to keep the session alive. UAs send periodic re-INVITE or UPDATE requests To resolve this problem, this extension defines a keepalive mechanismįor SIP sessions. Has no method to determine when the call state information no longer Situation, the call stateful proxy will retain state for the call and Stateful proxy will not know when the session has ended. When the BYE message gets lost due to network problems, a call User agent fails to send a BYE message at the end of a session, or Result is that call stateful proxies will not always be able toĭetermine whether a session is still active. Session specific mechanisms, proxies will not be able to do so. May be able to determine whether the session has timed out by using Mechanism for the sessions it establishes. The Session Initiation Protocol (SIP) does not define a keepalive IANA Registration of the 'timer' Option Tag. IANA Registration of the 422 (Session Interval Too IANA Registration of Min-SE and Session-Expires Generating Subsequent Session Refresh Requests. Generating an Initial Session Refresh Request. Min-SE, which conveys the minimum allowed value for the sessionĭonovan & Rosenberg Standards Track ġ. Session-Expires, which conveys the lifetime of the session, and The extension defines two new header fields: The refresh allows both userĪgents and proxies to determine whether the SIP session is stillĪctive. This extension allows for a periodic refresh of SIP sessions This document defines an extension to the Session Initiation Protocol Distribution of this memo is unlimited.Ĭopyright (C) The Internet Society (2005). Official Protocol Standards" (STD 1) for the standardization stateĪnd status of this protocol. Please refer to the current edition of the "Internet Internet community, and requests discussion and suggestions for This document specifies an Internet standards track protocol for the Session Timers in the Session Initiation Protocol (SIP) LSA group pacing also avoids a global synchronization of all locally generated LSAs that could happen in previous implementations.RFC 4028: Session Timers in the Session Initiation Protocol (SIP) Įrrata Exist Network Working Group S. The default LSA group pacing timer is 240 seconds and this timer can be configured on Cisco routers. The LSA group pacing provides the capabitily to wait for the pacing time interval before sending new LSAs in this way there is more efficient use of resources as multiple LSAs can be refreshed in a single LSU update packet. However, to achieve better scalability in OSPF rather then changing the LSA refresh timer it is important to use the functionality of LSA group pacing described here:Īs LSAs need to be refreshed in any case before max Age expires simply changing the LSA refresh timer does not provide great benefits. LSA refresh time interval can be changed in some vendor implementations (Juniper for example).Ĭisco routers look like are missing this capability. From the links provided by the other colleague and with some other web search we can say the following:
0 Comments
Leave a Reply. |