Atm Oam - HPE FlexNetwork MSR series Configuration Manual

IPoA
IP over ATM (IPoA) enables ATM to carry IP packets. In an IPoA implementation, ATM acts as the
data link layer protocol for the IP hosts on the same network. To enable these hosts to communicate
across an ATM network, IP packets must be encapsulated in ATM cells.
By making full use of the advantages of ATM, IPoA delivers excellent network performance and
mature QoS assurance.
IPoEoA
IP over Ethernet over ATM (IPoEoA) uses a three-layer architecture, with IP encapsulation at the top
layer, IP over Ethernet (IPoE) in the middle, and IPoEoA at the bottom.
IPoEoA is suitable where Ethernet packets are to be forwarded through ATM interfaces. In IPoEoA
applications, you can associate multiple PVCs with one Layer 3 virtual Ethernet (VE) interface. PVCs
associated with the same VE interface are interconnected at Layer 2.
PPPoA
PPP over ATM (PPPoA) enables ATM to carry PPP protocol packets. With PPPoA, PPP packets, in
which IP packets or other protocols' packets are encapsulated, are encapsulated in ATM cells. In this
implementation, ATM is the carrier of PPP packets and the communication process of PPPoA is
managed by PPP, which allows for flexibility and rich applications. To transmit PPP packets across
ATM, a virtual-template (VT) interface is required.
PPPoEoA
PPPoE over ATM (PPPoEoA) enables ATM to carry PPPoE protocol packets. With PPPoEoA,
Ethernet packets are encapsulated in ATM cells, through which you can use a PVC to implement the
functionality of Ethernet. To carry Ethernet frames over ATM, the virtual Ethernet (VE) interface was
introduced. The VE interface has Ethernet characteristics and can be dynamically created. The
following is the protocol stack used by the VE interface:
•
ATM PVC (the bottom layer).
•
Ethernet (the link layer).
•
Network layer and other upper layers (the same as those for common Ethernet interfaces).

ATM OAM

OAM has the following expansions:
•
Operation and Maintenance in the ITU-T I.610 recommendation (02/99).
•
Operation Administration and Maintenance in LUCENT APC User Manual (03/99).
Whichever expansion is used, OAM provides a way of detecting faults, isolating faults, and
monitoring network performance without interrupting ongoing services. By inserting OAM cells,
which are constructed in the standard ATM cell format, in cell streams, you can obtain specific
information about the network.
ATM OAM provides the following functions:
•
OAM Alarm Indication Signal/Remote Defect Indication—The PVC goes down when
specific number of successive AIS/RDI alarm cells are received. The PVC comes up when no
AIS/RDI alarm cells are received within the specified time.
•
OAM Continuity Check—OAM CC requires that one end of the PVC must be configured as
the CC cell source and the other end as the CC cell sink. If the detecting end fails to receive CC
cells within 3 seconds, the state of the PVC changes to down. The PVC comes up only after CC
cells are received again.
•
OAM F5 Loopback—Sends OAM F5 Loopback cells at the specified interval after you enable
OAM F5 Loopback transmission and retransmission detection and specify related parameters.
If the sender fails to receive a response cell within the specified interval, it sends an OAM F5
Loopback cell again. The state of the PVC is updated during the Loopback detection. The PVC
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