What Just Happened (WJH)

What Just Happened (WJH) provides real time visibility into network problems and has two components:

The WJH agent (nv-wjh.service) enables you to stream detailed and contextual telemetry for off-switch analysis with tools such as NVIDIA NetQ.
The WJH service enables you to diagnose network problems by looking at dropped packets. WJH can monitor layer 1, layer 2, layer 3, tunnel, buffer and ACL related issues. Cumulus Linux enables and runs the WJH service by default.

In Cumulus Linux 5.18 and later, the WJH agent is nv-wjh.service. In Cumulus Linux 5.17 and earlier, the WJH agent is what-just-happened.service.

Configure WJH

You can choose which packet drops you want to monitor by creating channels and setting the packet drop categories (layer 1, layer 2, layer 3, tunnel, buffer and ACL) you want to monitor.

A channel name must be between 4 and 16 characters long.
You can enable each trigger for a single channel only.

The following example configures two separate channels:

The forwarding channel monitors layer 2, layer 3, and tunnel packet drops.
The layer-1 channel monitors layer 1 packet drops.

cumulus@switch:~$ nv set system wjh channel forwarding trigger l2
cumulus@switch:~$ nv set system wjh channel forwarding trigger l3
cumulus@switch:~$ nv set system wjh channel forwarding trigger tunnel
cumulus@switch:~$ nv set system wjh channel layer-1 trigger l1
cumulus@switch:~$ nv config apply

The following example configures a channel to monitor buffer packet drops and a channel to monitor ACL packet drops:

cumulus@switch:~$ nv set system wjh channel buffer trigger buffer
cumulus@switch:~$ nv set system wjh channel acl1 trigger acl
cumulus@switch:~$ nv config apply

You can stop monitoring specific packet drops by unsetting a category in the channel list. The following command example stops monitoring layer 2 packet drops that are in the forwarding channel:

cumulus@switch:~$ nv unset system wjh channel forwarding trigger l2
cumulus@switch:~$ nv config apply

To remove a channel, run the nv unset system wjh channel <channel> command. The following command example removes the layer-1 channel:

cumulus@switch:~$ nv unset system wjh channel layer-1 
cumulus@switch:~$ nv config apply

Filter Traffic Drops

You can filter traffic drops to prevent them from being monitored based on the reason for the drop, the severity level (error, warning, or notice), or IP address.

The following table shows the drop reasons on which you can filter:

Traffic Drop Type	Drop Reasons
ACL	egress-cpu-port-acl egress-tunnel-acl ingress-router-acl egress-port-acl ingress-cpu-port-acl ingress-tunnel-acl egress-router-acl ingress-port-acl multi-points-acl
Buffer	packet-latency-threshold-crossed tail-drop port-tc-congestion-threshold-crossed wred
l2	dest-mac-is-reserved source-mac-is-multicast ingress-spanning-tree-filter source-mac-is-zero ingress-vlan-filtering unicast-egress-port-list-is-empty mlag-port-isolation unicast-mac-table-action-discard multicast-egress-port-list-is-empty vlan-or-vni-lookup-failed port-loopback-filter vlan-tagging-mismatch source-mac-equals-dest-mac
l3	blackhole-arp blackhole-route checksum-or-ipver-or-ipv4-ihl-too-short dest-ip-is-loopback-addr egress-router-intf-is-disabled ingress-router-intf-is-disabled ipv4-dest-ip-is-link-local ipv4-dest-ip-is-local-network ipv4-routing-table-unicast-miss ipv4-src-ip-is-limited-broadcast ipv6-dest-in-multicast-scope-ffx0 ipv6-dest-in-multicast-scope-ffx1 ipv6-routing-table-unicast-miss multicast-mac-mismatch non-ip-packet non-routable-pck packet-size-is-larger-than-router-intf-mtu packet-source-ip-cant-be-verified router-interface-loopback src-ip-equals-dest-ip src-ip-is-in-class-e src-ip-is-loopback-addr src-ip-is-multicast src-ip-is-unspecified ttl-value-is-too-small unicast-dest-ip-but-multicast-dest-mac unresolved-neighbor
Tunnel	decapsulation-error encapsulation-port-isolation overlay-switch-src-mac-equals-dest-mac overlay-switch-src-mac-equals-zero overlay-switch-src-mac-is-multicast

To filter traffic drops due to a specific reason, run the nv set system wjh channel <channel-id> drop-filter <filter-id> drop-type <type> drop-reason <reason> command.

To filter traffic drops due to a specific severity, run the nv set system wjh channel <channel-id> drop-filter <filter-id> drop-type <type> severity <severity-level> command.

To filter traffic drops with a specific IP address, run the nv set system wjh channel <channel-id> drop-filter <filter-id> ip <ip-address> command.

The <channel-id> is the channel name.
The <filter-id> is name you want to provide for the filter.
The <type> is acl, buffer, l2, l3, or tunnel.
The <reason> can be any reason listed in the table above.

The following example creates a filter called TUNNEL1 that prevents traffic drops from being monitored because the overlay switch source MAC equals the destination MAC:

cumulus@switch:~$ nv set system wjh channel forwarding drop-filter TUNNEL1 drop-type tunnel drop-reason overlay-switch-src-mac-equals-dest-mac
cumulus@switch:~$ nv config apply

The following example creates a filter called SEVERITY that prevents layer 2 traffic drops from being monitored with the severity level notice:

cumulus@switch:~$ nv set system wjh channel forwarding drop-filter SEVERITY drop-type l2 severity notice
cumulus@switch:~$ nv config apply

The following example creates a filter called IP-DROPS that prevents traffic drops with the IP address 10.10.10.10 from being monitored:

cumulus@switch:~$ nv set system wjh channel forwarding drop-filter IP-DROPS ip 10.10.10.10
cumulus@switch:~$ nv config apply

To unset a traffic drop filter, run the nv set system wjh channel <channel-id> drop-filter <filter-id> command.

To show traffic drop filter configuration, run the nv show system wjh channel <channel-id> drop-filter command.

cumulus@switch:~$ nv show system wjh channel forwarding drop-filter

Aggregation Interval and Cache Size

You can control the rate at which the switch sends events for a channel (the polling interval) and the number of WJH drops and aggregates to maintain in the cache (the aggregate cache size).

The polling interval for a channel can be between 5 and 300 seconds and the cache size between 500 and 5000.

The following example sets the aggregation interval for the forwarding channel to 100 seconds and the cache size to 1000:

cumulus@switch:~$ nv set system wjh channel forwarding polling-interval 100
cumulus@switch:~$ nv set system wjh channel forwarding aggregate-cache-size 1000
cumulus@switch:~$ nv config apply

To unset the aggregation interval for a channel, run the nv unset system wjh channel <channel-id> polling-interval command.
To unset the aggregate cache size, run the nv unset system wjh channel <channel-id> aggregate-cache-size command.

Latency and Congestion Thresholds

If you configure a channel to monitor buffer packet drops, you can specify latency and congestion thresholds to apply to buffer drops for all or specific traffic classes and interfaces. WJH collects and sends events when a metric crosses the thresholds.

Packet latency is the time spent in the switch.
Congestion is a percentage of the buffer occupancy on the switch.

The Spectrum-6 switch does not support latency thresholds.

The following example sets the latency threshold to 10 seconds for all traffic classes on ports swp1, swp2, and swp3 and the congestion threshold to 4 for traffic class 3 on all interfaces.

cumulus@switch:~$ nv set system wjh channel forwarding buffer-threshold latency tc all interface swp1-3 high 100
cumulus@switch:~$ nv set system wjh channel forwarding buffer-threshold congestion tc 3 interface all high 4
cumulus@switch:~$ nv config apply

To unset the packet latency threshold, run the nv unset system wjh channel <channel-id> buffer-threshold latency command.
To unset the packet congestion threshold, run the nv unset system wjh channel <channel-id> buffer-threshold congestion command.

To show the latency and congestion threshold configuration, run the nv show system wjh channel <channel-id> buffer-threshold command:

cumulus@switch:~$ nv show system wjh channel buffer buffer-threshold
Latency buffer threshold
===========================
    Traffic Class  Interface  High threshold
    -------------  ---------  --------------
    all            all        1000

Congestion buffer threshold
==============================
    Traffic Class  Interface  High threshold
    -------------  ---------  --------------
    all            swp1       20
                   swp2       20
                   swp3       20

Save Dropped Packets to a PCAP File

To save the most recent dropped packets to a PCAP file, run the nv action export system wjh packet-buffer command. The switch writes PCAP files to the /var/run/nv-wjh/ directory with a timestamped filename that the system chooses.

cumulus@switch:~$ nv action export system wjh packet-buffer

To exclude metadata in the file, add no-metadata to the command:

cumulus@switch:~$ nv action export system wjh packet-buffer no-metadata

Show Information about Dropped Packets

You can run the following commands to show information about dropped packets and diagnose problems.

NVUE Commands

To show information about packet drops for all the channels you configure, run the nv show system wjh packet-buffer command. The command output includes the reason for the drop and the recommended action to take.

cumulus@switch:~$ nv show system wjh packet-buffer
Packet
=========
    #     dMAC               dPort  Dst IP:Port    EthType  Drop group  IP Proto  Drop reason - Recommended action                                            Severity  sMAC               sPort   Src IP:Port     Timestamp              VLAN  sLAG  dLAG
    ----  -----------------  -----  -------------  -------  ----------  --------  --------------------------------------------------------------------------  --------  -----------------  ------  --------------  ---------------------  ----  ----  ----
    1     2c:5e:ab:a5:ae:f0  N/A    10.1.2.3:200   IPv4     ACL         N/A       Ingress port ACL - Validate ACL configuration                               Notice    00:02:00:00:00:01  swp1s0  192.0.2.10:100  26/07/03 12:46:29.238  N/A   N/A   N/A 
    2     02:03:04:05:06:07  N/A    10.2.3.4:200   IPv4     L2          N/A       Port loopback filter - Validate MAC table for this destination MAC          Error     00:02:00:00:00:01  swp1s0  224.0.0.1:100   26/07/03 12:46:29.238  N/A   N/A   N/A 
    3     2c:5e:ab:a5:ae:f0  N/A    10.1.2.3:200   IPv4     L2          N/A       Source MAC is Zero - Bad packet was received from peer                      Error     00:00:00:00:00:00  swp1s0  10.1.2.3:100    26/07/03 12:46:29.238  N/A   N/A   N/A 
    4     02:03:04:05:06:07  N/A    127.0.0.1:200  IPv4     L2          N/A       Port loopback filter - Validate MAC table for this destination MAC          Error     00:02:00:00:00:01  swp1s0  224.0.0.1:100   26/07/03 12:46:29.238  N/A   N/A   N/A 
    5     02:03:04:05:06:07  N/A    10.1.2.3:200   IPv4     L2          N/A       Port loopback filter - Validate MAC table for this destination MAC          Error     00:02:00:00:00:01  swp1s0  10.1.2.3:100    26/07/03 12:46:29.238  N/A   N/A   N/A 
    6     2c:5e:ab:a5:ae:f0  N/A    10.1.2.3:200   IPv4     L3          N/A       Source IP equals destination IP - Bad packet was received from the peer     Error     00:02:00:00:00:01  swp1s0  10.1.2.3:100    26/07/03 12:46:29.238  N/A   N/A   N/A 

Packet ACL
=============
    #     Rule                                                                                                                                                                    
    ----  ------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1     Priority[0];KEY[L3_TYPE: IPV4];KEY[SIP: 192.0.2.10/255.255.255.255];KEY[SRC_PORT: 65777];ACTION[COUNTER: COUNTER_ID = 614400];ACTION[FORWARD: FORWARD_ACTION = DISCARD];

Packet Buffer Info
=====================
No Data

To show the most recent aggregate buffer drop events, up to the maximum aggregate cache size specified, run the nv show system wjh aggregate-buffer command.

cumulus@switch:~$ nv show system wjh aggregate-buffer
Aggregate Event
==================
    Event ID  Drop group  Count  Severity  Drop reason - Recommended action                                            Start timestamp        End timestamp          sPort   sLAG  dPort  dLAG  VLAN  sMAC               dMAC               EthType  Src IP:Port     Dst IP:Port    IP Proto
    --------  ----------  -----  --------  --------------------------------------------------------------------------  ---------------------  ---------------------  ------  ----  -----  ----  ----  -----------------  -----------------  -------  --------------  -------------  --------
    1         L3          30     Error     Destination IP is loopback address - Bad packet was received from the peer  26/07/03 10:29:38.281  26/07/03 10:30:07.287  swp1s0  N/A   N/A    N/A   N/A   00:02:00:00:00:01  2c:5e:ab:a5:ae:f0  IPv4     10.1.2.3:100    127.0.0.1:200  udp     
    2         L2          30     Error     Source MAC is Zero - Bad packet was received from peer                      26/07/03 10:29:38.281  26/07/03 10:30:07.287  swp1s0  N/A   N/A    N/A   N/A   00:00:00:00:00:00  2c:5e:ab:a5:ae:f0  IPv4     10.1.2.3:100    10.1.2.3:200   udp     
    3         L2          30     Error     Port loopback filter - Validate MAC table for this destination MAC          26/07/03 10:29:38.281  26/07/03 10:30:07.287  swp1s0  N/A   N/A    N/A   N/A   00:02:00:00:00:01  02:03:04:05:06:07  IPv4     10.1.2.3:100    10.1.2.3:200   udp     
    4         L2          30     Error     Port loopback filter - Validate MAC table for this destination MAC          26/07/03 10:29:38.281  26/07/03 10:30:07.287  swp1s0  N/A   N/A    N/A   N/A   00:02:00:00:00:01  02:03:04:05:06:07  IPv4     224.0.0.1:100   10.2.3.4:200   udp     
    5         ACL         33     Notice    Ingress port ACL - Validate ACL configuration                               26/07/03 10:29:35.280  26/07/03 10:30:07.287  swp1s0  N/A   N/A    N/A   N/A   00:02:00:00:00:01  2c:5e:ab:a5:ae:f0  IPv4     192.0.2.10:100  10.1.2.3:200   udp  

Aggregate Event ACL
======================
    Event ID  Rule                                                                                                                                                                    
    --------  ------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    5         Priority[0];KEY[L3_TYPE: IPV4];KEY[SIP: 192.0.2.10/255.255.255.255];KEY[SRC_PORT: 65777];ACTION[COUNTER: COUNTER_ID = 614400];ACTION[FORWARD: FORWARD_ACTION = DISCARD];

Aggregate Event Buffer
=========================
No Data

To show layer 1 buffer events, run the nv show system wjh l1-buffer command.

cumulus@switch:~$ nv show system wjh l1-buffer
Event ID  Port   State  Port down reason                Start timestamp        End timestamp          State change count  Symbol error count  CRC error count
--------  -----  -----  ------------------------------  ---------------------  ---------------------  ------------------  ------------------  ---------------
1         swp1   Up     N/A                             26/07/23 15:31:53.848  26/07/23 15:47:45.628  1                   0                   0
2         swp10  Down   Cable/transceiver is unplugged  26/07/23 15:31:53.848  26/07/23 15:47:45.628  0                   0                   0
3         swp11  Down   Cable/transceiver is unplugged  26/07/23 15:31:53.848  26/07/23 15:47:45.628  0                   0                   0
4         swp12  Down   Cable/transceiver is unplugged  26/07/23 15:31:53.848  26/07/23 15:47:45.628  0                   0                   0

To show the configuration for all WJH channels and the total drops, run the nv show system wjh channel command.

cumulus@switch:~$ nv show system wjh channel
Channel name  Trigger(s)      Polling interval  Type                                     Aggregate cache size  Total drops
------------  --------------  ----------------  ---------------------------------------  --------------------  -----------
acls          ACL             30                WJH_USER_CHANNEL_CYCLIC_AND_AGGREGATE_E  1024                  109        
buffer        BUFFER          30                WJH_USER_CHANNEL_CYCLIC_AND_AGGREGATE_E  1024                  0          
forwarding    L2, L3, TUNNEL  30                WJH_USER_CHANNEL_CYCLIC_AND_AGGREGATE_E  1024                  749        
layer-1       L1              30                WJH_USER_CHANNEL_AGGREGATE_E             1024                  0

To show the configuration for a specific WJH channel and the total drops, run the nv show system wjh channel <channel> command.

cumulus@switch:~$ nv show system wjh channel buffer
                      operational                              applied
--------------------  ---------------------------------------  -------
polling-interval      30                                       30
aggregate-cache-size  1024                                     1024
drop-category-list    BUFFER
type                  WJH_USER_CHANNEL_CYCLIC_AND_AGGREGATE_E
total-drops           0

Latency buffer threshold
===========================
    Traffic Class  Interface  High threshold
    -------------  ---------  --------------
    all            all        1000

Congestion buffer threshold
==============================
    Traffic Class  Interface  High threshold
    -------------  ---------  --------------
    all            swp1       20
                   swp2       20
                   swp3       20

Linux Commands

You can run the nv-wjh-cli poll command from the command line with the following options:

Command Option	Description
`--data`	You can specify `drops`, `aggregates`, or `l1`. `drops` shows individual drops for each packet. `aggregates` shows aggregated drops. `l1` shows layer 1 port-state aggregates (only valid for channels with layer 1 in their trigger list).
`--output-type`	You can specify `table`, `json`, or `pcap`. `pcap` is only for data drops (`--data drops`).
`--no-metadata`	Writes PCAP output without embedded metadata. This option is only valid with `--data drops` and `--output-type pcap`.
`--channels <channel-name>,<channel-name>`	A comma-separated list of the channels to show. If you do not provide the `--channels` option, the command shows all configured channels.
`dump`	Shows diagnostic information. The output includes channel configuration, snapshots for each channel, and memory statistics. The command saves the output to the `/var/log/nv-wjh/diags-dump/<timestamp>` file.

The following example shows aggregated drops:

cumulus@switch:~$ nv-wjh-cli poll --data aggregates

The following command saves dropped packets in the forwarding channel to a file in PCAP format without metadata:

cumulus@switch:~$ nv-wjh-cli poll --data drops --output-type pcap --channels forwarding --no-metadata

WJH Events

This section provides the supported WJH events with a brief description of each.

Layer 1 Drops

Layer 1 drop events describe why a port is in the down state.

Reason	Description
Link training failure	The link is not able to go operational up due to link training failure.
Port state changes counter	The cumulative number of state changes.
Symbol error counter	The cumulative number of symbol errors.
CRC error counter	The cumulative number of CRC errors.

In addition to the reason, the information provided for these drops includes:

Parameter	Description
Corrective Action	Recommended actions to resolve the port down state.
First Timestamp	The date and time the port was marked as down for the first time.
Ingress Port	The port accepting incoming traffic.
CRC Error Count	The number of CRC errors that this port generated.
Symbol Error Count	The number of Symbol errors that this port generated.
State Change Count	The number of state changes on this port.
OPID	Operation identifier; for internal purposes.
Is Port Up	Indicates if the port is in an Up (true) or Down (false) state.

Layer 2 Drops

Layer 2 drop events describe why the switch drops packets at layer 2.

Reason	Severity	Description
MLAG port isolation	Notice	Not supported for port isolation implemented with the system ACL.
Destination MAC is reserved (DMAC=01-80-C2-00-00-0x)	Error	The link cannot use the MAC address.
VLAN tagging mismatch	Error	The source and destination VLAN tags do not match.
Ingress VLAN filtering	Error	Frames whose port is not a member of the VLAN are discarded.
Ingress spanning tree filter	Notice	The port is in a Spanning Tree blocking state.
Unicast MAC table action discard	Notice	The packet is dropped due to a MAC table configuration rule.
Multicast egress port list is empty	Warning	No ports are defined for multicast egress.
Port loopback filter	Error	The port is operating in loopback mode; packets are being sent to itself (source MAC address is the same as the destination MAC address).
Source MAC is multicast	Error	Packets have a multicast source MAC address.
Source MAC equals destination MAC	Error	The source MAC address is the same as the destination MAC address.

In addition to the reason, the information provided for these drops includes:

Parameter	Description
Source Port	The port ID where the link originates.
Source IP	The port IP address where the link originates.
Source MAC	The port MAC address where the link originates.
Destination Port	The port ID where the link terminates.
Destination IP	The port IP address where the link terminates.
Destination MAC	The port MAC address where the link terminates.
First Timestamp	The date and time this link is marked as down for the first time.
Aggregate Count	The total number of dropped packets.
Protocol	The ID of the communication protocol running on this link.
Ingress Port	The port accepting incoming traffic.
OPID	The operation identifier; for internal purposes.

Router Drops

Router drop events describe why the server is unable to route a packet.

Reason	Severity	Description
Non-routable packet	Notice	The packet has no route in the routing table.
Blackhole route	Warning	The packet was received with an action equal to discard.
Unresolved next hop	Warning	The next hop in the route is unknown.
Blackhole ARP/neighbor	Warning	The packet was received with a blackhole adjacency.
IPv6 destination in multicast scope FFx0:/16	Notice	The packet was received with a multicast destination address in FFx0:/16 address range.
IPv6 destination in multicast scope FFx1:/16	Notice	The packet was received with a multicast destination address in FFx1:/16 address range.
Non-IP packet	Notice	Cannot read the packet header because it is not an IP packet.
Destination IP is loopback address	Error	Cannot read the packet because the destination IP address is a loopback address (dip=>127.0.0.0/8).
Source IP is multicast	Error	Cannot read the packet because the source IP address is a multicast address (ipv4 SIP => 224.0.0.0/4).
Source IP is in class E	Error	Cannot read the packet because the source IP address is a Class E address.
Source IP is loopback address	Error	Cannot read the packet because the source IP address is a loopback address (ipv4 => 127.0.0.0/8 for ipv6 => ::1/128).
Source IP is unspecified	Error	Cannot read the packet because the source IP address is unspecified (ipv4 = 0.0.0.0/32; for ipv6 = ::0).
Checksum or IP ver or IPv4 IHL too short	Error	Cannot read the packet due to a header checksum error or IP version mismatch, or because the IPv4 header length is too short.
Multicast MAC mismatch	Error	For IPv4, the destination MAC address is not equal to {0x01-00-5E-0 (25 bits), DIP[22:0]} and the DIP is multicast. For IPv6, the destination MAC address is not equal to {0x3333, DIP[31:0]} and the DIP is multicast.
Source IP equals destination IP	Error	The packet has a source IP address equal to the destination IP address.
IPv4 source IP is limited broadcast	Error	The packet has a broadcast source IP address.
IPv4 destination IP is local network (destination = 0.0.0.0/8)	Error	The packet has an IPv4 destination address that is a local network (destination=0.0.0.0/8).
IPv4 destination IP is link-local (destination in 169.254.0.0/16)	Error	The packet has an IPv4 destination address that is a local link.
Ingress router interface is disabled	Warning	The packet is destined to a different subnet but cannot be routed because the ingress router interface is disabled.
Egress router interface is disabled	Warning	The packet is destined to a different subnet but cannot be routed because the egress router interface is disabled.
IPv4 routing table (LPM) unicast miss	Warning	There is no route available in the routing table for the packet.
IPv6 routing table (LPM) unicast miss	Warning	There is no route available in the routing table for the packet.
Router interface loopback	Warning	The packet has a destination IP address that is local. For example, SIP = 1.1.1.1, DIP = 1.1.1.128.
Packet size is larger than MTU	Warning	The packet has a larger MTU configured than the VLAN.
TTL value is too small	Warning	The packet has a TTL value of 1.

Tunnel Drops

Tunnel drop events describe why a tunnel is down.

Reason	Severity	Description
Overlay switch - source MAC is multicast	Error	The source MAC address of the overlay packet is multicast.
Overlay switch - source MAC equals destination MAC	Error	The source MAC address of the overlay packet is the same as the destination MAC address. Supported on Spectrum-4 and later.
Decapsulation error	Error	Decapsulation produced an incorrect format for the packet. For example, encapsulation of a packet with many VLANs or IP options on the underlay can cause decapsulation to result in a short packet.
Source MAC equals Zero	Error	The source MAC address equals 0.
Encapsulation port isolation	Error	Encapsulation port isolation.

Buffer Drops

Buffer drop events describe why the server buffer has dropped packets.

Reason	Severity	Description
Tail drop	Warning	Tail drop is enabled and the buffer queue is filled to maximum capacity.
WRED	Warning	Weighted Random Early Detection is enabled and the buffer queue is filled to maximum capacity or the RED engine dropped the packet as a random congestion prevention.
Port TC Congestion Threshold Crossed	Warning	The percentage of the occupancy buffer exceeded or dropped below the specified high or low threshold.
Packet Latency Threshold Crossed	Warning	The time a packet spent within the switch exceeded or dropped below the specified high or low threshold. Not supported on Spectrum-1 and Spectrum-6.

ACL Drops

ACL drop events describe why an ACL has dropped packets.

Reason	Severity	Description
Ingress port ACL	Notice	An ACL action is set to deny on the physical ingress port or bond.
Ingress router ACL	Notice	An ACL action is set to deny on the ingress switch virtual interfaces (SVIs).
Egress port ACL	Notice	An ACL action is set to deny on the physical egress port or bond.
Egress router ACL	Notice	An ACL action is set to deny on the egress SVIs.

Considerations

Buffer Packet Drop Monitoring

Buffer packet drop monitoring is available on a switch with Spectrum-2 and later.
Buffer packet drop monitoring uses a SPAN destination. If you configure SPAN, ensure that you do not exceed the total number of SPAN destinations allowed for your switch ASIC type; see SPAN and ERSPAN. If you need to remove the SPAN destination that buffer packet drop monitoring uses, delete the buffer monitoring drop category with the NVUE nv unset system wjh channel buffer trigger buffer command.

WJH and the NVIDIA NetQ Agent

When you enable the NVIDIA NetQ agent on the switch, the WJH service stops and does not run. If you disable the NVIDIA NetQ service and want to use WJH, run the following commands to enable and start the WJH service:

NVUE Commands

cumulus@switch:~$ nv set system wjh state enabled
cumulus@switch:~$ nv config apply

Linux Commands

cumulus@switch:~$ sudo systemctl enable nv-wjh
cumulus@switch:~$ sudo systemctl start nv-wjh

What Just Happened (WJH)

Configure WJH

Filter Traffic Drops

Aggregation Interval and Cache Size

Latency and Congestion Thresholds

Save Dropped Packets to a PCAP File

Show Information about Dropped Packets

WJH Events

Layer 1 Drops

Layer 2 Drops

Router Drops

Tunnel Drops

Buffer Drops

ACL Drops

Considerations

Buffer Packet Drop Monitoring

WJH and the NVIDIA NetQ Agent

Products

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