cancel
Showing results for 
Search instead for 
Did you mean: 
cancel

EPFT Queries

124
Views
0
Helpful
0
Comments

Question:

Want to enable Feature EPFT with “routing-protocols-enable”. However ,it is throwing an error and ask to configure the following command: “non-subscriber-interfaces mac” which once enabled drops the traffic without any penalty.

Answer:

EPFT for routing-protocols can be enabled with “non-subscriber-interfaces mac” command only which means bad actor identification will be done on mac basis .When a bad actor is identified based on mac there will be complete drop no penalty  policing will be done for penalty policing to happen please change the config as “non-subscriber-interfaces”.

The complete drop is for traffic from bad actor. All other mac on the interface should be able to pass traffic via the interface.

 

 

Question

My understanding of enabling ‘routing-protcols-enable’ for EPFT is that it prevents routing protocols (eg: BGP) from triggering any ‘bad actor’ condition; Is that correct?

 

Answer:

Without enabling "routing-protocols-enable" command:

> EPFT functionality bypasses all routing protocols by default. This is done to explicitly avoid dropping of necessary control-plane packets like route updates. Control-plane is already protected via LPTS.

 

> By default EPFT is not enabled, thus BGP packets <updates> will not fall under penalty as per design. By default LPTS has configured rate for BGP packets to be policed if it goes over the limit.

 

The correct command to check the same is following:

 

show lpts pifib hardware police location <>

show lpts pifib dynamic-flows statistics location <>

show lpts pifib hardware entry location <> | be <SIP>

SIP > Source IP with which peering is done and who sent big updates to check the rate of traffic.

 

Once EPFT for routing protocols is enabled:

 

lpts punt excessive-flow-trap
non-subscriber-interfaces mac^
routing-protocols-enable

 

> EPFT, if enabled for routing-protocols can cause issues with dropping the traffic from bad actor<which can be updates if sent at a very high rate, and are not expected>. Usually normal updates are never identified as bad actor.

 

* Bad actor is a term to state a user sending huge amount of “for-us” traffic

Spoiler
^ The reason for using mac keyword is to avoid the problem where if 1 user sends  a bad flow, then other users sharing the same IFH will also get penalised.

To check if the protocol is configured under EPFT, following command can be used:

 

show lpts punt excessive-flow-trap

 

+++++++++++

To enable it, we have to configure “routing-protocols-enable” under lpts punt excessive-flow-trap” and following logs are seen to confirm if it is enabled or not:

 

Enabled

Command:Show lpts punt excessive-flow-trap trace

Spoiler
Sep 8 01:06:45.688 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_verify_enable_nonsubscribers, event: 0x3, batch size: 1, item #: 1
Sep 8 01:06:45.695 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_apply_enable_nonsubscribers, event: 0x3
Sep 8 01:06:45.695 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_apply_enable_nonsubscribers, flow trap ENABLED
Sep 8 01:06:45.695 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_config_apply_func: item 1 of 1 = last in batch
Sep 8 01:06:45.695 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_spp_msg_send: Added 0 ifh to exclude list
Sep 8 01:07:18.516 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_verify_enable_routing_protocols, event: 0x3, batch size: 1, item #: 1
Sep 8 01:07:18.522 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_apply_enable_routing_protocols, event: 0x3
Sep 8 01:07:18.522 flowtrap/event 0/RSP0/CPU0 t1 Sending packet to spp classifier routing_protocol_enable=1
Sep 8 01:07:18.522 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_config_apply_func: item 1 of 1 = last in batch

Removed routing-protocols-enable

lpts punt excessive-flow-trap

non-subscriber-interfaces     >>> without mac keyword routing-protocols are not enabled.

 

Disabled:

Spoiler

Sep 8 01:08:29.890 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_verify_enable_nonsubscribers, event: 0x2, batch size: 1, item #: 1
Sep 8 01:08:29.897 flowtrap/error 0/RSP0/CPU0 t1 sub_copp_config_verify_func: backend_verify item nonsubscribers, 'infra_flowtrap' detected the 'warning' condition 'Code(22)'
Sep 8 01:08:50.092 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_verify_enable_routing_protocols, event: 0x4, batch size: 1, item #: 1
Sep 8 01:08:50.098 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_apply_enable_routing_protocols, event: 0x4
Sep 8 01:08:50.098 flowtrap/event 0/RSP0/CPU0 t1 Sending packet to spp classifier routing_protocol_enable=0
Sep 8 01:08:50.098 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_config_apply_func: item 1 of 1 = last in batch
Sep 8 01:08:50.098 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_spp_msg_send: Added 0 ifh to exclude list
Sep 8 01:08:50.106 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_verify_enable_nonsubscribers, event: 0x2, batch size: 1, item #: 1
Sep 8 01:08:50.114 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_apply_enable_nonsubscribers, event: 0x2
Sep 8 01:08:50.114 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_apply_enable_nonsubscribers, flow trap ENABLED
Sep 8 01:08:50.114 flowtrap/event 0/RSP0/CPU0 t1 sub_copp_config_apply_func: item 1 of 1 = last in batch

 

Question:

 My understanding is also that it’s correct behaviour for the above knob to only be useable in conjunction with ‘non-subscriber-interfaces mac’ enabled.

Answer:

 The EPFT feature for routing protocols is supported only with non subscriber mac interfaces.

It only supports source based MAC filtering.

Once a bad actor is identified all the traffic with that particular source will be dropped for penalty-timeout which can be modified as follows:

 

lpts punt excessive-flow-trap

penalty-rate arp 10

penalty-rate icmp 0

penalty-rate igmp 50

penalty-rate ip 100

penalty-timeout ospf 0

penalty-timeout bgp 0

exclude interface <back_bone_interface> // Can exclude both physical and sub-interface

dampening 15

non-subscriber-interface

 

Question:

Want to confirm why the default parameters are set <seen by the output of command “show lpts punt exc info” >though EPFT is not configured?

Answer:

 The output of this command is just to let us know that once EPFT is enabled than following parameters will be set which can be changed by using commands. If we want to see whether EPFT is enabled or not. It can be confirmed via following command:

 

- Show lpts punt excessive-flow-trap trace | in Elephant

- Show lpts punt excessive-flow-trap trace | in routing_protocol_enable   >> it should have value =1

 

>> The output will show Elephant trap enabled or disabled and it will also show various parameters for which it is enabled once configured.

 

 

 

CreatePlease to create content
Content for Community-Ad
August's Community Spotlight Awards