H3C Technologies H3C SR8800 - Manual (Page 12)

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An rt_VBR connection is described by the PCR, sustainable cell rate (SCR) and maximum burst size (MBS).
A station using the rt_VBR service is allowed to send burst traffic at PCR with the maximum traffic size
being MBS without packet loss while the average cell rate being SCR.
nrt_VBR
The nrt_VBR service supports non-real-time applications with burst traffic. An nrt_VBR connection is
described by PCR, SCR and MBS. The nrt_VBR service is suitable for applications that are sensitive to cell
loss but not to delay.
UBR
The UBR service does not make any service quality commitment, guaranteeing neither CLR nor cell delay.
When traffic congestion occurs, cells of the UBR service are always dropped first. The UBR service is
suitable for applications that have low requirements for delay and bandwidth.
Introduction to InARP
On an ATM PVC connection, you can use the Inverse Address Resolution Protocol (InARP) to obtain the
IP address of the remote end connected to the PVC. Thus, you do not need to manually configure the IP
address of the remote end. The following figure shows how InARP works:
Figure 3 Inverse address resolution procedure of InARP
ATM OAM
OAM stands for Operation And Maintenance in the ITU-T I.610 recommendation (02/99) and
Operation Administration and Maintenance in LUCENT APC User Manual (03/99).
Whichever expansion is adopted, 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.
OAM F5 loopback
The OAM F5 loopback function of ATM works as follows on a PVC:
Each side of the PVC sends OAM cells to its peer periodically. On receiving an OAM cell from the sender,
the receiver returns the OAM cell to the sender. If the sender receives the cell within the specified period,