Junos OS

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  • 1.  OAM

    Posted 02-07-2018 10:52


    Could any one say about OAM feature in Juniper Devices ?


    What exactly OAM does?


    Thank you.

  • 2.  RE: OAM

    Posted 02-07-2018 11:34

  • 3.  RE: OAM
    Best Answer

    Posted 02-07-2018 20:02

    OAM as the name suggests stands for Operation, Administration and Management. This feature is mostly used in following areas:


    1. Ethernet OAM

    2. MPLS OAM


    Ethernet OAM  - This again has 2 parts:

    a. LFM - link fault management which is usually used between direct links.  - IEEE 802.3ah


    • Failure detection on physical links in both directions, as well as unidirectional failures.
    • Ability to put a port in link-loopback mode remotely for diagnostics.
    • Report and receive link error events such as framing errors.


    b. CFM - connectivity fault management which is usually used across the domains. - IEEE 802.1ag

    • CFM is used to monitor an Ethernet network at a per-service level, unlike LFM, which functions at the physical link level.
    • Fault monitoring using the continuity check protocol. This is a neighbor discovery and health check protocol which discovers and maintains adjacencies at the VLAN or link level.
    • Path discovery and fault verification using the linktrace protocol. Similar to IP traceroute, this protocol maps the path taken to a destination MAC address through one or more bridged networks between the source and destination.
    • Fault isolation using the loopback protocol. Similar to IP ping, this protocol works with the continuity check protocol during troubleshooting.

        CFM can be used at two levels:

    • By the service provider to check the connectivity among its provider edge (PE) routers
    • By the customer to check the connectivity among its customer edge (CE) routers



    MPLS OAM - This is nothing but configuring BFD for MPLS LSPs:








  • 4.  RE: OAM

    Posted 02-14-2018 02:14
    Thank you.