Chapter 36 Diagnostic
VMG1312-B10C User’s Guide
268
36.5 OAM Ping
Click
Maintenance > Diagnostic > OAM Ping
to open the screen shown next. Use this screen to
perform an OAM (Operation, Administration and Maintenance) F4 or F5 loopback test on a PVC. The
Device sends an OAM F4 or F5 packet to the DSLAM or ATM switch and then returns it to the
Device. The test result then displays in the text box.
ATM sets up virtual circuits over which end systems communicate. The terminology for virtual
circuits is as follows:
Figure 157
Virtual Circuit Topology
Think of a virtual path as a cable that contains a bundle of wires. The cable connects two points and
wires within the cable provide individual circuits between the two points. In an ATM cell header, a
VPI (Virtual Path Identifier) identifies a link formed by a virtual path; a VCI (Virtual Channel
Identifier) identifies a channel within a virtual path. A series of virtual paths make up a virtual
circuit.
F4 cells operate at the virtual path (VP) level, while F5 cells operate at the virtual channel (VC)
level. F4 cells use the same VPI as the user data cells on VP connections, but use different
predefined VCI values. F5 cells use the same VPI and VCI as the user data cells on the VC
connections, and are distinguished from data cells by a predefined Payload Type Identifier (PTI) in
the cell header. Both F4 flows and F5 flows are bidirectional and have two types.
• segment F4 flows (VCI=3)
• end-to-end F4 flows (VCI=4)
• segment F5 flows (PTI=100)
• end-to-end F5 flows (PTI=101)
OAM F4 or F5 tests are used to check virtual path or virtual channel availability between two DSL
devices. Segment flows are terminated at the connecting point which terminates a VP or VC
segment. End-to-end flows are terminated at the end point of a VP or VC connection, where an ATM
link is terminated. Segment loopback tests allow you to verify integrity of a PVC to the nearest
neighboring ATM device. End-to-end loopback tests allow you to verify integrity of an end-to-end
PVC.
Note: The DSLAM to which the Device is connected must also support ATM F4 and/or F5
to use this test.
•
Virtual Channel (VC)
Logical connections between ATM devices
•
Virtual Path (VP)
A bundle of virtual channels
•
Virtual Circuits
A series of virtual paths between circuit end points
Содержание VMG1312-B10C
Страница 4: ...Contents Overview VMG1312 B10C User s Guide 4 Diagnostic 265 Troubleshooting 271 ...
Страница 14: ...Table of Contents VMG1312 B10C User s Guide 14 ...
Страница 15: ...15 PART I User s Guide ...
Страница 16: ...16 ...
Страница 22: ...Chapter 1 Introducing the Device VMG1312 B10C User s Guide 22 ...
Страница 33: ...33 PART II Technical Reference ...
Страница 34: ...34 ...
Страница 64: ...Chapter 5 Broadband VMG1312 B10C User s Guide 64 ...
Страница 100: ...Chapter 6 Wireless VMG1312 B10C User s Guide 100 ...
Страница 124: ...Chapter 7 Home Networking VMG1312 B10C User s Guide 124 ...
Страница 166: ...Chapter 10 Network Address Translation NAT VMG1312 B10C User s Guide 166 ...
Страница 176: ...Chapter 12 Interface Group VMG1312 B10C User s Guide 176 ...
Страница 192: ...Chapter 14 Firewall VMG1312 B10C User s Guide 192 ...
Страница 198: ...Chapter 16 Parental Control VMG1312 B10C User s Guide 198 ...
Страница 208: ...Chapter 18 Certificates VMG1312 B10C User s Guide 208 ...
Страница 211: ...Chapter 19 VPN VMG1312 B10C User s Guide 211 Figure 121 IPSec VPN Add ...
Страница 224: ...Chapter 20 Log VMG1312 B10C User s Guide 224 ...
Страница 234: ...Chapter 24 IGMP Status VMG1312 B10C User s Guide 234 ...
Страница 238: ...Chapter 25 xDSL Statistics VMG1312 B10C User s Guide 238 ...
Страница 242: ...Chapter 27 User Account VMG1312 B10C User s Guide 242 ...
Страница 248: ...Chapter 30 TR 064 VMG1312 B10C User s Guide 248 ...
Страница 252: ...Chapter 31 Time Settings VMG1312 B10C User s Guide 252 ...
Страница 264: ...Chapter 35 Configuration VMG1312 B10C User s Guide 264 ...
Страница 270: ...Chapter 36 Diagnostic VMG1312 B10C User s Guide 270 ...
Страница 288: ...Appendix B Legal Information VMG1312 B10C User s Guide 288 ...