Billion BiPAC 8700VAX(L)-1600, Руководство пользователя, Страница: 322 / 327

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Ethernet OAM
8700VAX(L)-1600 offers industry standard OAM capabilities to enable network providers to provision
and operate their networks with full visibility and control, simply and efficiently to minimize ongoing
OPEX.
Both peers should be Ethernet-OAM-enabled.
There are two phases of how Ethernet OAM is usually realized:
1.)
Ethernet Link OAM:
Ethernet in the First Mile (EFM) Link OAM as defined in IEEE 802.3ah,
Designed for testing and maintaining access links between EFM-OAM-enabled devices on L2. It
includes a set of discovery, link monitoring, remote failure detection and remote loop-back protocols.
2).
Ethernet Service OAM (802.1ag/Y1.1731):
designed to detect and isolate connectivity faults
within the customer service path and ensure a health service end to end.
802/1ag/CFM
enable Ethernet services to be partitioned into maintenance domains with
maintenance endpoints (MEP) and intermediate points (MIP) across which continuity check, link
trace and loopback tests can be performed as needed to validate connection integrity.
Y1.1731
extends beyond CFM (802.1ag) to support performance monitoring and testing of key
Ethernet service attributes including frame loss, frame delay, and frame delay variation, which are
necessary for ensuring conformance to SLAs and verifying end to end service quality.
Ethernet Link OAM(802.3ah):
Enable to activate Ethernet in the First Mile (EFM) Link OAM to do
link fault management.
Ethernet Service OAM (802.1ag/Y1.1731):
Enable to activate Ethernet Service OAM check
mechanism, including connectivity fault management and performance monitoring..
Linktrace:
Operators trigger linktrace protocol to perform path discovery and fault isolation in their
networks.Link Trace messages otherwise known as Mac Trace Route are Multicast frames that a
MEP transmits to track the path (hop-by-hop) to a destination MEP which is similar in concept to
User Datagram Protocol (UDP) Trace Route. Each receiving MEP sends a Trace route Reply directly
to the Originating MEP, and regenerates the Trace Route Message.
Loopback:
Loopback protocol is used to verify and isolate connectivity faults. Loop-back messages
otherwise known as Mac ping are Unicast frames that a MEP transmits, they are similar in concept
to an Internet Control Message Protocol (ICMP) Echo (Ping) messages, sending Loop-back to
successive MIPs can determine the location of a fault. Sending a high volume of Loop-back
Messages can test bandwidth, reliability, or jitter of a service, which is similar to flood ping. A MEP
can send a Loop-back to any MEP or MIP in the service. Unlike CCMs, Loop back messages are
administratively initiated and stopped.