This article explains the reason for arp resolution failure for interface (including AF ) on MPC10/11E card.
ARP entry is not present on AF0 interface. While doing monitor traffic interface on both side Device, we seen IN+OUT arp packets on remote Device interface but only OUT arp packets on Local Device interface.
root@Remote-MX2020> monitor traffic interface af2 no-resolve matching arp
08:43:12.443703 In arp who-has 172.16.1.1 tell 172.16.1.2
08:43:12.443781 Out arp reply 172.16.1.1 is-at fc:96:43:41:43:4a
08:43:30.942880 In arp who-has 172.16.1.1 tell 172.16.1.2
08:43:30.942949 Out arp reply 172.16.1.1 is-at fc:96:43:41:43:4a
root@Local-MX2020> monitor traffic interface af0 matching arp
09:01:36.649279 Out arp who-has 172.16.1.1 tell 172.16.1.2
09:01:48.550312 Out arp who-has 172.16.1.1 tell 172.16.1.2
09:02:06.350278 Out arp who-has 172.16.1.1 tell 172.16.1.2
09:02:18.350263 Out arp who-has 172.16.1.1 tell 172.16.1.2
The received arp reply packet from peer are dropping with "undefined nexthop opcode" exception incrementing on ingress PFE. The exceptions can be dumped to see the packet.
root@Local-MX2020-fpc8:pfe> show jnh exceptions level terse inst 0
Reason Type Packets Bytes
==================================================================
Ucode Internal
----------------------
undefined nexthop opcode DISC( 36) 4789 220294
The Control Feature List's CLI policer has jnh in broken state and have value as zero.
root@Local-MX2020-fpc8:pfe> show interfaces logical af0.0
IflName: af0.0 IflIndex: 330 Subunit: 0 Type: 3 IsLocal: Yes
IffCount: 5 IfdIndex: 146 ActiveNodeToken: None StatsMgr Map: Present
InitTime: Fri Sep 22 06:07:11 2023 StateChangeTime: NA
IflSnmpIndex: 681 IflFlags: 0x000000000400c000 IflLinkFlags: 0x0000
OuterVlanID: 4095 InnerVlanID: 4095 NumVlanTags: 0
Encap: ENET2 PfeInst: 255 IsBridgedIfl: False
MediaInfo: SCookie:0x0 SChannel:0 SFamily:0 SLength:0
VRF: 0
IfOifToken: 2263
IfRegistryToken: 2264
OutputSelectToken: None
Ingress Feature List:
Container token: 2259
#7 SetIIF tokens:
Mask : 0x2
[ SetIIF:2253 Counter:2252 ]
#8 SetVrfId tokens:
Mask : 0x0
[ SetVrfId:2254 ]
#25 PtypeMux tokens:
[ PtypeMux:2257 RelativeCounter:2255 AftList:2256 ]
#30 FabricOut tokens:
[ FabricOut:2258 ]
Egress Feature List:
Container token: 2262
#9 SetOIF tokens:
[ SetOIF:2260 ]
#17 PtypeMux tokens:
[ PtypeMux:2261 ]
#24 Rewrite tokens:
[ Rewrite:2319 ]
#41 AfWanOut tokens:
[ AfWanOut:2251 ]
Iff Feature List Token Summary:
Name Ingress Egress
IPv4 2265 2267
MPLS 2303 2305
IPv6 2273 2275
CLNP 2270 2272
Control 2307 2309
IPv4 Feature:
Local: 140.222.11.231, Destination: 140.222.11.230/31
Container token: 2265
#6 Classifier tokens:
[ Classifier:2310 ]
#20 RouteLkup tokens:
Mask : 0x1
[ RouteLkup:1563 ]
Egress feature list:
Container token: 2267
#0 SetOIF tokens:
[ SetOIF:2266 ]
#12 Redirect tokens:
[ Redirect:5629662 ]
MPLS Feature:
Container token: 2303
[ Classifier:2317 ]
[ RouteLkup:1689 ]
Container token: 2305
[ SetOIF:2304 ]
#18 CosSetRwMask tokens:
[ CosSetRwMask:2320 ]
IPv6 Feature:
Local: 2001:506:0:1::ad, Destination: 2001:506:0:1::ac/127
Local: fe80::da53:9a0f:fc25:2001, Destination: fe80::/64
Container token: 2273
[ Classifier:2315 ]
[ RouteLkup:1718 ]
Container token: 2275
[ SetOIF:2274 ]
[ Redirect:3917 ]
CLNP Feature:
Container token: 2270
[ RouteLkup:1703 ]
Container token: 2272
[ SetOIF:2271 ]
Control Feature:
Container token: 2307
#13 Control tokens:
[ Control:2306 ]
#14 CliPolicer tokens:
[ CliPolicer:5107996 ]
[ RouteLkup:55 ]
Container token: 2309
[ SetOIF:2308 ]
root@Local-MX2020-fpc8:pfe> show sandbox token 5107996
AftNode : AftFilter token:5107996 group:0 tag:None nodeMask:Default{NodeType:AftFilter Filter Template Token:1906 Next-Filter Token:18446744073709551615 Index:17000 Node mask: 0xffffffffffffffff Instance Key:0 Instance Type:Default}
{Interface info Ifd Index:261 Total BW:200000000000}
{Bandwidth:0} {Bandwidth:0} {Bandwidth:0} {Bandwidth:0} {Bandwidth:0} {Bandwidth:0} {Bandwidth:0} {Bandwidth:100000000000} {Bandwidth:0} {Bandwidth:0} {Bandwidth:0} {Bandwidth:0}
{cosIfdRate:0} {cosIfdRate:0} {cosIfdRate:0} {cosIfdRate:0} {cosIfdRate:0} {cosIfdRate:0} {cosIfdRate:0} {cosIfdRate:100000000000} {cosIfdRate:0} {cosIfdRate:0} {cosIfdRate:0} {cosIfdRate:0}
{cosIflRate:0} {cosIflRate:0} {cosIflRate:0} {cosIflRate:0} {cosIflRate:0} {cosIflRate:0} {cosIflRate:0} {cosIflRate:100000000000} {cosIflRate:0} {cosIflRate:0} {cosIflRate:0} {cosIflRate:0}
JnhHandle : JnhHandleFilter Jnh:0x0 PfeInst:ff Paddr:0x0 Vaddr:0x0 AppType:FW
Filter Index: 17000 pfe_mask: 0xffffffff, pfe_num: 0
Unknown jnh-type(0) in jnh(0x0000000000000000)! <<<<<<<<<<<<<<
Filter is not interface specific 17000
DFW Memory Usage:
Previous nodes count: 2
Next nodes count : 1
Entries count : 0
Since default ARP(Address Resolution Protocol) policer is not programmed, using manual ARP policer or static ARP can be used as a workaround. Rebooting the FPC will re-programme the default policer. For permanent fix, get fix of the PR https://prsearch.juniper.net/problemreport/PR1795940