以太网环保护交换协议(erps).ppt

G.8032 Ethernet Ring Protection OverviewMarch, 2008 ITU-T Q9 – SG 15 •本资料由-大学生创业|创业|创业网 减肥药排行榜|淘宝最好的减肥药|什么减肥药效果最好|减肥瘦身药|Agenda§G.8032 Recommendation Introduction§G.8032 Objectives and Principles§G.8032 Concepts§G.8032 Protection Switching§G.8032 R-APS Messages§G.8032 Items Under Study•本资料由-大学生创业|创业|创业网 减肥药排行榜|淘宝最好的减肥药|什么减肥药效果最好|减肥瘦身药|2ITU-T SG15/Q9 G.8032 Recommendation§G.8032 Recommendation consented February 2008ŸThis Recommendation defines the APS protocol and protection switching mechanisms for ETH layer ring topologies. Included are details pertaining to bridged ring protection characteristics, architectures and the ring APS protocol.J A NF E BM A RA P RM A YJ U NJ U LA U GS E PO C TN O VD E CJ A NF E BM A RA P RM A YJ U NJ U LA U GS E PO C TN O VD E CJ A NF E BM A R200620072008G.8032 Proposals G.8032 Proposals and Contributionsand ContributionsG.8032 Converged ProposalsG.8032 Converged ProposalsG.8032 ERP Work G.8032 ERP Work Item Approved in Item Approved in ITU-TITU-TG.8032 Objective, G.8032 Objective, Principles, and Principles, and Requirements SettingRequirements SettingG.8032 Recommendation G.8032 Recommendation ConsentConsent•本资料由-大学生创业|创业|创业网 减肥药排行榜|淘宝最好的减肥药|什么减肥药效果最好|减肥瘦身药|3G.8032 Objectives and Principles§Use of standard 802 MAC and OAM frames around the ring. Uses standard 802.1Q (and amended Q bridges), but with xSTP disabled. §Ring nodes supports standard FDB MAC learning, forwarding, flush behaviour and port blocking/unblocking mechanisms. §Prevents loops within the ring by blocking one of the links (either a pre-determined link or a failed link). §Monitoring of the ETH layer for discovery and identification of Signal Failure (SF) conditions. §Protection and recovery switching within 50 ms for typical rings. §Total communication for the protection mechanism should consume a very small percentage of total available bandwidth.4G.8032 Terms and ConceptsRing Protection Link (RPL) – Link designated by mechanism that is blocked during Idle state to prevent loop on Bridged ringRPL Owner – Node connected to RPL that blocks traffic on RPL during Idle state and unblocks during Protected stateLink Monitoring – Links of ring are monitored using standard ETH CC OAM messages (CFM)Signal Fail (SF) – Signal Fail is declared when ETH trail signal fail condition is detectedNo Request (NR) – No Request is declared when there are no outstanding conditions (e.g., SF, etc.) on the nodeRing APS (R-APS) Messages – Protocol messages defined in Y.1731 and G.8032Automatic Protection Switching (APS) Channel - Ring-wide VLAN used exclusively for transmission of OAM messages including R-APS messages5G.8032 TimersG.8032 specifies the use of different timers to avoid race conditions and unnecessary switching operations §WTR (Wait to Restore) Timer – Used by the RPL Owner to verify that the ring has stabilized before blocking the RPL after SF Recovery §Hold-off Timers – Used by underlying ETH layer to filter out intermittent link faults ŸFaults will only be reported to the ring protection mechanism if this timer expires6Controlling the Protection MechanismProtection switching triggered by §Detection/clearing of Signal Failure (SF) by ETH CC OAM §Remote requests over R-APS channel (Y.1731) §Expiration of G.8032 timersR-APS requests control the communication and states of the ring nodes §Two basic R-APS messages specified - R-APS(SF) and R- APS(NR) §RPL Owner may modify the R-APS(NR) indicating the RPL is blocked: R-APS(NR,RB)Ring nodes may be in one of two states §Idle – normal operation, no link/node faults detected in ring §Protecting – Protection switching in effect after identifying a signal fault7§ Physical topology has all nodes connected in a ring§ ERP guarantees lack of loop by blocking the RPL (link between 6 otherwise End TLV]lastEnd TLV (0)Defined by Y.1731Defined by G.8032Non-specified content11R-APS Specific InformationSpecific information (32octets) defined by G.8032 §Request/Status(4bits) – ‘1011’ = SF | ’0000’ = NR | Other = Future §Status – RB (1bit) – Set when RPL is blocked (used by RPL Owner in NR) §Status – DNF (1bit) – Set when FDB Flush is not necessary (Future) §NodeID (6octets) – MAC address of message source node (Informational) §Reserved1(4bits), Status Reserved(6bits), Reserved2(24octets) - Future development123487654321876543218765432187654321Request /StateReserved 1StatusNode ID (6 octets)R BD N FStatus Reserved(Node ID)Reserved 2 (24 octets)12Items Under StudyG.8032 is currently an initial recommendation that will continue to be enhanced. The following topics are under study for future versions of the recommendation:§Interconnected rings scenarios: shared node, shared links §RPL blocked at both e。