Interface And Hardware Component Configuration Guide For Cisco Ncs 5500 Series Routers, Ios Xr Release - Cisco NCS 5500 Series Configuration Manual

Ethernet CFM
All the MEPs in a service must transmit CCMs at the same interval. IEEE 802.1ag defines 7 possible intervals
that can be used:
• 3.3ms
• 10ms
• 100ms
• 1s
• 10s
• 1 minute
• 10 minutes
A MEP detects a loss of connectivity with one of its peer MEPs when some number of CCMs have been
missed. This occurs when sufficient time has passed during which a certain number of CCMs were expected,
given the CCM interval. This number is called the loss threshold, and is usually set to 3.
CFM is supported only on interfaces which have Layer 2 transport feature enabled.
CCM messages carry a variety of information that allows different defects to be detected in the service. This
information includes:
• A configured identifier for the domain of the transmitting MEP. This is referred to as the Maintenance
Domain Identifier (MDID).
• A configured identifier for the service of the transmitting MEP. This is referred to as the Short MA
Name (SMAN). Together, the MDID and the SMAN make up the Maintenance Association Identifier
(MAID). The MAID must be configured identically on every MEP in the service.
• These are restrictions on the type of MAID that are supported for sessions with time interval of less than
1 minute. The MAID supports two types of formats on offloaded MEPs:

Interface and Hardware Component Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release

6.1.x
32
• No Domain Name Format
◦ MD Name Format = 1-NoDomainName
◦ Short MA Name Format = 3 - 2 bytes integer value
◦ Short MA NAme Length = 2 - fixed length
◦ Short MA Name = 2 bytes of integer
• 1731 Maid Format
◦ MD Name Format = 1-NoDomainName
◦ MA Name Format(MEGID Format) = 32
◦ MEGID Length = 13 - fixed length
◦ MEGID(ICCCode) = 6 Bytes
◦ MEGID(UMC) = 7 Bytes
◦ ITU Carrier Code (ICC) - Number of different configurable ICC code - 15 (for each NPU)
◦ Unique MEG ID Code (UMC) - 4
Configuring Ethernet OAM