This article explains what the " May 29 09:59:30.554 ####### fpc2 ppmd_cfm_proto_receive:3659 SLR parsing failed " syslog message means and what must be done to resolve the failure.

The following log message is seen when the device receives a CFM SLR packet from the peer:

ppmd_cfm_proto_receive:3659 SLR parsing failed

The ppmd_cfm_proto_receive:3659 SLR parsing failed error is a generic error (E_FAIL) that is seen while parsing an Ethernet OAM connectivity fault management (CFM) Synthetic Loss Reply (SLR) packet.

The below packet capture indicates that the MX router received a malformed CFM packet following which the "SLR parsing failed" was logged:

No.     Time           Source                Destination Protocol Length Info
15 3.213673       HewlettP_26:d7:9d     JuniperN_6a:9a:96     CFM 26     Type Synthetic Loss Reply (SLR))[Malformed Packet]

Frame 15: 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface \Device\NPF_{C23D202F-AD1E-49C0-9865-3209FB90A227}, id 0
Ethernet II, Src: HewlettP_26:d7:9d (c4:34:6b:26:d7:9d), Dst: JuniperN_6a:9a:96 (84:b5:9c:6a:9a:96)
802.1Q Virtual LAN, PRI: 0, DEI: 0, ID: 13
CFM EOAM 802.1ag/ITU Protocol, Type Synthetic Loss Reply (SLR))
CFM SLR PDU
Flags: 0x00
First TLV Offset: 16
...0 1100 0001 1100 = Source MEP ID: 3100
...0 1011 1110 1110 = Responder MEP ID: 3054
[Malformed Packet: CFM]
[Expert Info (Error/Malformed): Malformed Packet (Exception occurred)]
[Malformed Packet (Exception occurred)]
[Severity level: Error]
[Group: Malformed]

To resolve this error, perform the following steps:

1. Check if the adjacent production device has SLR capability.

2. Check why the adjacent device was sending illegally formatted SLR OAM packets to the router.

3. Work with the adjacent device to identify the reason.