802.1ag_802.3ah_Y.1731_以太网OAM笔记

802.1ag CFM/802.3ah EFM OAM/Y.1731 ETH OAM

学习笔记

一、802.3ah............................................................................................................................... .........1

二、802.1ag............................................................................................................................... .........5

三、Y.1731........................................................................................................................................10

相关协议:

1）IEEE 802.1ag 连通性故障管理(CFM:Connectivity Fault Management)

2）IEEE 802.3ah 第一英里的以太网(EFM:Ethernet in the First Mile)，其中第 57 章的以太网 OAM

2）网络级以太网 OAM 技术：多应用于网络的接入汇聚层，用于监测整个网络的连通性、定位网络的连通性故障，典型协议为

CFD 协议。（CFD:Connectivity Fault Detection） -->802.1ag, Y.1731

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一、802.3ah

EFM OAM 工作在数据链路层，其协议报文被称为 OAMPDU.+

The frame transmission rate is limited to a maximum of 10 frames per second; therefore, the impact of OAM on normal

operations is negligible.+

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a)

Destination Address (DA). The DA in OAMPDUs is the Slow_Protocols_Multicast address. 0x0180-C200-0002 慢速协议报

e) Flags. The Flags field contains status bits.

Additional diagnostic information may be sent using the Event Notification OAMPDU.

主要的 Flag:

值 含义 备注

2 Critical Event ----1 = A critical event has occurred.

----0 = A critical event has not occurred.

1 Dying Gasp ----1 = An unrecoverable local failure condition has occurred.

----0 = An unrecoverable local failure condition has not occurred.

0 Link Fault The PHY has detected a fault has occurred in the receive direction

of the local DTE (e.g., link, Physical layer).

0x01

Event

Notification OAMPDU，事件通知 OAMPDU

用于对连接本端与远端 OAM 实体的链路上所发生的故障进行告警

0x04

Loopback Control OAMPDU，环回控制 OAMPDU

用于检测链路质量和定位链路故障，该报文中带有使能/去使能信息，用来开启/关闭远端环回功能

Command Description（命令描述）

This field

contains the

OAMPDU data

and any

necessary pad.

Implementations shall support OAMPDUs at least minFrameSize in length.

6h) FCS

This field is the Frame Check Sequence

+

以太网 OAM 功能建立在以太网 OAM 连接的基础上。

以太网 OAM 连接的建立过程也称为 Discovery 阶段，即本端 OAM 实体发现远端 OAM 实体、并与之建立稳定对话的过程。

在这个过程中，相连的 OAM 实体通过交互 Information OAMPDU 通报各自的以太网 OAM 配置信息和本端支持的以太网 OAM

能力信息。当 OAM 实体收到对端的配置参数后，决定是否建立 OAM 连接。

以太网 OAM 的连接模式有两种：主动模式和被动模式；

以太网 OAM 连接只能由主动模式的 OAM 实体发起，而被动模式的 OAM 实体只能等待对端 OAM 实体的连接请求；

• OAM configuration (capabilities)

Advertises the capabilities of the local OAM entity. With this information a peer can determine, what functions are supported

Includes the maximum OAMPDU size for receipt and delivery. This information along with the rate limiting of 10 frames per

second can be used to limit the bandwidth allocated to OAM traffic.

• Platform identity

A combination of an organization unique identifier (OUI) and 32-bits of vendor-specific information. OUI allocation, controlled

by the IEEE, is typically the first three bytes of a MAC address.

+以太网 OAM 能够有效提高以太网的管理和维护能力，保障网络的稳定运行，其主要功能包括：

1)链路性能监测：对链路的各种性能进行监测，包括对丢包、时延和抖动等的衡量，以及对各类流量的统计；