📄 rfc2209.txt
字号:
point to the cPSB, then do the following. - Copy into the cPSB the OutInterface_list from the PSB, if any, pointed to by fPSB. Clear OutInterface_list and turn on the Local_Only flag in the PSB pointed to by fPSB, if any. - Turn off the Local_Only flag in the cPSB and set fPSB to point to cPSB. 4. If Rt_OutL differs from OutInterface_list of the PSB pointed to by fPSB, then: - Update the OutInterface_list of the PSB from Rt_OutL, and then execute the PATH LOCAL REPAIR event sequence below. o If the Path_Refresh_Needed flag is now off, drop the PATH message and return. Otherwise (the path state is new or modified), do refreshes, upcalls, and state updates as follows. 1. If this PATH message came from a network interface and not from a local application, make a Path Event upcall for each local application for this session: Call: <Upcall_Proc>( session-id, PATH_EVENT, flags, sender_tspec, sender_template [ , ADSPEC] [ , POLICY_DATA] ) 2. If OutInterface_list is not empty, execute the PATH REFRESH event sequence (below) for the sender defined by the PSB. 3. Search for any matching reservation state, i.e., an RSB whose Filter_spec_list includes a FILTER_SPEC matching the SENDER_TEMPLATE and whose OI appears in the OutInterface_list, and make this the `active RSB'.Braden & Zhang Informational [Page 7] RFC 2209 RSVP-Message Processing September 1997 If none is found, drop the PATH message and return. 4. Execute the RESV REFRESH sequence (below) for the PHOP in the PSB. 5. Execute the event sequence UPDATE TRAFFIC CONTROL to update the local traffic control state if necessary. This sequence will turn on the Resv_Refresh_Needed flag if the traffic control state has been modified in a manner that should trigger a reservation refresh. If so, execute the RESV REFRESH sequence for the PHOP in the PSB. o Drop the PATH message and return. PTEAR MESSAGE ARRIVES o Search for a PSB whose (Session, Sender_Template) pair matches the corresponding objects in the message. If no matching PSB is found, drop the PTEAR message and return. o Forward a copy of the PTEAR message to each outgoing interface listed in OutInterface_list of the PSB. o Find each RSB that matches this PSB, i.e., whose Filter_spec_list matches Sender_Template in the PSB and whose OI is included in OutInterface_list. 1. If the RSB style is explicit, then: - Delete from Filter_spec_list the FILTER_SPEC that matches the PSB. - if Filter_spec_list is now empty, delete the RSB. 2. Otherwise (RSB style is wildcard) then: - If this RSB matches no other PSB, then delete the RSB. 3. If an RSB was found, execute the event sequence UPDATE TRAFFIC CONTROL (below) to update the traffic control state to be consistent with the current reservation and path state. o Delete the PSB. o Drop the PTEAR message and return.Braden & Zhang Informational [Page 8] RFC 2209 RSVP-Message Processing September 1997 PERR MESSAGE ARRIVES o Search for a PSB whose (SESSION, SENDER_TEMPLATE) pair matches the corresponding objects in the message. If no matching PSB is found, drop the PERR message and return. o If the previous hop address in the PSB is the local API, make an error upcall to the application: Call: <Upcall_Proc>( session-id, PATH_ERROR, Error_code, Error_value, Node_Addr, Sender_Template [ , Policy_Data] ) Any SENDER_TSPEC or ADSPEC object in the message is ignored. Otherwise, send a copy of the PERR message to the PHOP IP address. o Drop the PERR message and return. RESV MESSAGE ARRIVES Initially, Refresh_PHOP_list is empty and the Resv_Refresh_Needed and NeworMod flags are off. These variables are used to control immediate reservation refreshes. o Determine the Outgoing Interface OI The logical outgoing interface OI is taken from the LIH in the NHOP object. (If the physical interface is not implied by the LIH, it can be learned from the interface matching the IP destination address). o Check the path state 1. If there are no existing PSB's for SESSION then build and send a RERR message (as described later) specifying "No path information", drop the RESV message, and return. 2. If a PSB is found with a matching sender host but the SrcPorts differ and one of the SrcPorts is zero, then build and send an "Ambiguous Path" PERR message, drop the RESV message, and return.Braden & Zhang Informational [Page 9] RFC 2209 RSVP-Message Processing September 1997 o Check for incompatible styles. If any existing RSB for the session has a style that is incompatible with the style of the message, build and send a RERR message specifying "Conflicting Style", drop the RESV message, and return. Process the flow descriptor list to make reservations, as follows, depending upon the style. The following uses a filter spec list struct Filtss of type FILTER_SPEC* (defined earlier). For FF style: execute the following steps independently for each flow descriptor in the message, i.e., for each (FLOWSPEC, Filtss) pair. Here the structure Filtss consists of the FILTER_SPEC from the flow descriptor. For SE style, execute the following steps once for (FLOWSPEC, Filtss), with Filtss consisting of the list of FILTER_SPEC objects from the flow descriptor. For WF style, execute the following steps once for (FLOWSPEC, Filtss), with Filtss an empty list. o Check the path state, as follows. 1. Locate the set of PSBs (senders) that route to OI and whose SENDER_TEMPLATEs match a FILTER_SPEC in Filtss. If this set is empty, build and send an error message specifying "No sender information", and continue with the next flow descriptor in the RESV message. 2. If the style has explicit sender selection (e.g., FF or SE) and if any FILTER_SPEC included in Filtss matches more than one PSB, build and send a RERR message specifying "Ambiguous filter spec" and continue with the next flow descriptor in the RESV message. 3. If the style is SE and if some FILTER_SPEC included in Filtss matches no PSB, delete that FILTER_SPEC from Filtss. 4. Add the PHOP from the PSB to Refresh_PHOP_list, if the PHOP is not already on the list.Braden & Zhang Informational [Page 10] RFC 2209 RSVP-Message Processing September 1997 o Find or create a reservation state block (RSB) for (SESSION, NHOP). If the style is distinct, Filtss is also used in the selection. Call this the "active RSB". o If the active RSB is new: 1. Set the session, NHOP, OI and style of the RSB from the message. 2. Copy Filtss into the Filter_spec_list of the RSB. 3. Copy the FLOWSPEC and any SCOPE object from the message into the RSB. 4. Set NeworMod flag on. o If the active RSB is not new, check whether Filtss from the message contains FILTER_SPECs that are not in the RSB; if so, add the new FILTER_SPECs and turn on the NeworMod flag. o Start or restart the cleanup timer on the active RSB, or, in the case of SE style, on each FILTER_SPEC of the RSB that also appears in Filtss. o If the active RSB is not new, check whether STYLE, FLOWSPEC or SCOPE objects have changed; if so, copy changed object into RSB and turn on the NeworMod flag. o If the message contained a RESV_CONFIRM object, copy it into the RSB and turn on NeworMod flag. o If the NeworMod flag is off, continue with the next flow descriptor in the RESV message, if any. o Otherwise (the NeworMod flag is on, i.e., the active RSB is new or modified), execute the UPDATE TRAFFIC CONTROL event sequence (below). If the result is to modify the traffic control state, this sequence will turn on the Resv_Refresh_Needed flag and make a RESV_EVENT upcall to any local application. If the UPDATE TRAFFIC CONTROL sequence fails with an error, then delete a new RSB but restore the original reservation in an old RSB. o Continue with the next flow descriptor.Braden & Zhang Informational [Page 11] RFC 2209 RSVP-Message Processing September 1997 o When all flow descriptors have been processed, check the Resv_Refresh_Needed flag. If it is now on, execute the RESV REFRESH sequence (below) for each PHOP in Refresh_PHOP_list. o Drop the RESV message and return. If processing a RESV message finds an error, a RERR message is created containing flow descriptor and an ERRORS object. The Error Node field of the ERRORS object is set to the IP address of OI, and the message is sent unicast to NHOP. RTEAR MESSAGE ARRIVES Processing of a RTEAR message roughly parallels the processing of the corresponding RESV message A RTEAR message arrives with an IP destination address matching outgoing interface OI. Flag Resv_Refresh_Needed is initially off and Refresh_PHOP_list is empty. o Determine the Outgoing Interface OI The logical outgoing interface OI is taken from the LIH in the NHOP object. (If the physical interface is not implied by the LIH, it can be learned from the interface matching the IP destination address). o Process the flow descriptor list in the RTEAR message to tear down local reservation state, as follows, depending upon the style. The following uses a filter spec list struct Filtss of type FILTER_SPEC* (defined earlier). For FF style: execute the following steps independently for each flow descriptor in the message, i.e., for each (FLOWSPEC, Filtss) pair. Here the structure Filtss consists of the FILTER_SPEC from the flow descriptor. For SE style, execute the following steps once for (FLOWSPEC, Filtss), with Filtss consisting of the list of FILTER_SPEC objects from the flow descriptor. For WF style, execute the following steps once for (FLOWSPEC, Filtss), with Filtss an empty list.Braden & Zhang Informational [Page 12] RFC 2209 RSVP-Message Processing September 1997 1. Find an RSB matching (SESSION, NHOP). If the style is distinct, Filtss is also used in the selection. Call this the "active RSB". If no active RSB is found, continue with next flow descriptor. 2. Check the style If the active RSB has a style that is incompatible with the style of the message, drop the RTEAR message and return. 3. Delete from the active RSB each FILTER_SPEC that matches a FILTER_SPEC in Filtss. 4. If all FILTER_SPECs have now been deleted from the active RSB, delete the active RSB. 5. Execute the UPDATE TRAFFIC CONTROL event sequence (below) to update the traffic control state to be consistent with the reservation state. If the result is to modify the traffic control state, the Resv_Refresh_Needed flag will be turned on and a RESV_EVENT upcall will be made to any local application.⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -