23.1.1 Overview
In addition to enterprise LANs, Ethernet is also starting to be used for wide area networks. As a result, maintenance and management functionality on par with SONET and ATM is required for Ethernet.
The CFM functionality uses the following types of functionality to maintain and manage Layer 2 networks:
-
Continuity checks
This functionality always monitors whether information is delivered correctly to the destination (accessibility and continuity) between management points.
-
Loopback
After a failure is detected, the loopback functionality identifies the area affected by the failure on the route (loopback test).
-
Linktrace
After a failure is detected, the linktrace functionality verifies the route to a management point (route searching within a Layer 2 network).
The following figure shows a configuration example of CFM.
|
|
![[Figure Data]](./GRAPHICS/ZU219010.GIF)
- <Structure of this section>
(1) CFM functions
CFM is defined by IEEE 802.1ag and has the functionality described in the table below. The Switch supports all of this functionality.
|
Name |
Description |
|---|---|
|
Continuity Check (CC) |
Continuously monitors accessibility between management points. |
|
Loopback |
Loopback test. Executes ping-equivalent functionality in Layer 2. |
|
Linktrace |
Route search. Executes traceroute-equivalent functionality in Layer 2. |
(2) Configuring CFM
The table below describes the elements configuring CFM. The scope of CFM operation is maintenance and management defined by domains, MAs, MEPs, and MIPs.
|
Name |
Description |
|---|---|
|
Domains (Maintenance Domain) |
For management purposes, a group on the network to which CFM is applied |
|
MA (Maintenance Association) |
A group of VLANs used to subdivide a domain for management purposes |
|
MEP (Maintenance association End Point) |
A management end point. Set a MEP on the port at the domain boundary for each MA. In addition, the port is used to execute the CFM functionality. |
|
MIP (Maintenance domain Intermediate Point) |
A management intermediate point. This management point is located inside a domain. |
|
MP (Maintenance Point) |
A management point and the generic name used for a MEP or a MIP |