Configuring CC

About CC

After the CC function is configured, MEPs in an MA can periodically send CCM frames to maintain connectivity.

You must configure CC before you use the MEP ID of the remote MEP to configure other CFD functions. This restriction does not apply when you use the MAC address of the remote MEP to configure other CFD functions.

When the lifetime of a CCM frame expires, the link to the sending MEP is considered disconnected. When setting the CCM interval, use the settings described in Table 5.

Table 5: CCM interval field encoding

CCM interval field	Transmission interval	Maximum CCM lifetime
1	10/3 milliseconds	35/3 milliseconds
2	10 milliseconds	35 milliseconds
3	100 milliseconds	350 milliseconds
4	1 second	3.5 seconds
5	10 seconds	35 seconds
6	60 seconds	210 seconds
7	600 seconds	2100 seconds

NOTE:

The value range for the interval field is 1 to 7. If you set the value to 1 or 2, the continuity check might work incorrectly due to hardware restrictions..
The CCM messages with an interval field value of 1 to 3 are short-interval CCM messages. The CCM messages with an interval field value of 4 to 7 are long-interval CCM messages.

Restrictions and guidelines

When you configure the CCM interval, follow these restrictions and guidelines:

Configure the same CCM interval field value for all MEPs in the same MA.
After the CCM interval field is modified, the MEP must wait for another CCM interval before sending CCMs.

When you configure CC on devices with auxiliary CPUs, follow these restrictions and guidelines:

If the device has multiple cards with auxiliary CPUs, all MEPs on the device send CCM frames through one of these cards. If the sending card is removed, another card takes over to send CCM frames. If all these cards are removed, MEPs with a short CCM interval immediately stop sending CCM frames. MEPs with a long CCM interval send CCM frames through the cards where the MEPs are created.
The cards without auxiliary CPUs discard short-interval CCM messages to reduce impact on CPU performance. If your device does not have an auxiliary CPU, configure a long CCM interval for all MEPs.

Procedure

Enter system view.
system-view
(Optional.) Set the CCM interval field.
cfd cc interval interval-value service-instance instance-id
By default, the interval field value is 4.
Enter Layer 2 Ethernet interface view or Layer 2 aggregate interface view.
interface interface-type interface-number
Enable CCM sending on a MEP.
cfd cc service-instance instance-id mep mep-id enable
By default, CCM sending is disabled on a MEP.

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