Juniper JUNOSE 11.1.X - LINK LAYER CONFIGURATION 4-7-2010, Configuration Manual

Page: 47 / 774

removes entries that cannot be successfully refreshed after three successive failed
InARP requests.
Removing Circuits
If a circuit is removed, it is also removed from the ARP table, but not from the static
map. If the circuit is reconfigured, a new ARP table entry is generated from the
existing map entry. If the circuit uses InARP, the ARP table entry is immediately
removed on removal of the circuit.
If a subinterface is removed, all associated circuits and their associated ARP table
entries are removed.
Operations, Administration, and Management of ATM Interfaces
ATM interfaces support the OAM standards of the ITU, per recommendation I.610.
OAM provides VC/VP integrity and fault and performance management. The E Series
router supports F4 and F5 ATM OAM fault management, loopback, and continuity
check (CC) cells. These cells perform fault detection and notification, loopback testing,
and link integrity.
ATM uses F4 and F5 cell flows as follows:
■
F4—Used in VPs
■
F5—Used in VCs
ATM interfaces always generate and validate CRC-10 checksums on OAM cells.
For information about configuring OAM on the router, see the following sections:
■
“Configuring OAM” on page 33
■
“Configuring F5 OAM for Data PVCs” on page 51
End-to-End and Segment Endpoints
An ATM connection consists of a group of points. This OAM implementation provides
management for the following points:
■
Connection endpoint—The end of a VC/VP connection where the ATM cells are
terminated
■
Segment endpoint—The end of a connection segment
Fault Management
ATM uses two types of fault management cells to convey defect information to the
endpoints of a VP/VC:
■
Alarm indication signal (AIS) cells, which are used to indicate a fault to the
downstream endpoint. AIS cells contain defect type and defect location fields,
Operations, Administration, and Management of ATM Interfaces
■ 15
Chapter 1: Configuring ATM