Re: [pmacct-discussion] nfacctd pretag.map with mpls_vpn_rd

[Paolo Lucente]

Hi Andy,

Amazing, great to have you rolling with this. And i will also close 
Issue 770, thanks for confirming.


Paolo


On 21/3/24 06:01, Andrew Lake wrote:

Hi Paolo,

Thanks for the explanation and talking through this with me. Indeed 
flow_to_rd.map was the missing piece I needed. I have things working the 
way we wanted by generating a flow_to_rd.map that matches on the 
router_ip and mpls_vpn_id. Your SNMP suggestion would also work for us 
too since we have all that info readily available, but going the 
mpls_vpn_id route keeps the number of entries smaller and should change 
less. I had previously played around with flow_to_rd.map but for 
whatever reason convinced myself it wasn’t affecting the path lookups. 
It is very clearly working though now, no many thanks for your guidance.


 From my perspective issue 770 can also be closed.

Thanks,
Andy

On March 19, 2024 at 4:33:08 AM, Paolo Lucente (pa...@pmacct.net 
) wrote:




Hi Andy,

Amazing! So probably, after all, we may bash Issue 770 on GitHub -- 
coolio.


Let me recap situation so that you can correct me where i am wrong and
fill any gaps. You have flows, these (all or some) have a VRFID; you
have BGP feeds and there, obviously, you have MPLS VPN RD. The linking
pin is the flow_to_rd_map (see examples/flow_to_rd.map.example and
CONFIG-KEYS).

The map allows you to work in a few modes: 'id' is the output, the RD as
you want to match it in the BGP feed; you can output the RD in a few
different modes: basing on router / interface, for example; or VRFID; or
the MPLS label stack. Probably you want the VRFID scenario.

Problem that often people come across is .. what is the VRFID anyway,
where do i source the info? Of course some vendor-specific SNMP polling;
so some people i have seen preferring to go to the router / interface
scenario, because if you have some sort of inventory / source of truth
that is easy to compose.

Probably the least popular scenario is composing the map with MPLS
labels but now in the software-defined world, potentially with
controllers, that sporadically happens too.

Paolo


On 19/3/24 05:57, Andrew Lake wrote:
> Hi Paolo,
>  
> Ok maybe I have gotten headed down the wrong path. It sounds like you’re  
> saying nfacctd in normal collector mode should be able to take into  
> account the VRF when asking the BGP daemon to lookup the AS path for a  
> flow? This would be my ideal situation, and the replication setup I had  
> was just trying to get around the fact that I didn’t think it did based  
> on some preliminary testing. I might have given up too soon when it  
> didn’t appear to be working though.
>  
> Are there any extra options in nfacctd.conf or similar I need to set to  
> make it take the VRF into consideration for the path lookup?
>  
> What fields does it look at in the BGP message and IPFIX messages to  
> make the decision? rd and mpls_vpn_rd respectively? Mainly just asking  
> so I can debug if something was not getting set properly by our routers  
> in either of the message sets when I was testing.
>  
>  
> Thanks again,

> Andy
>  
> On March 16, 2024 at 1:06:48 AM, Paolo Lucente (pa...@pmacct.net 

> >) wrote:
>  
>>

>> Hi Andy,
>>
>> Thanks for opening the issue on GitHub and the kind words.
>>
>> Thing is all you want to achieve is supported in pmacct when working in
>> collector mode where the proper inspection of each flow is performed.
>>
>> Why don't you leave the tee part barebone and implement these features
>> in the collector? Just an idea as a perfectly valid answer could be that
>> performing this enrichment in the replicator then also 3rd party tools
>> could benefit from this info. Let me know.
>>
>> Paolo
>>
>>
>> On 16/3/24 01:51, Andrew Lake wrote:
>> > Hi Paolo,
>> >   
>> > Thanks for reply! I have created the issue as requested:   
>> > https://github.com/pmacct/pmacct/issues/770 

>> >
>> > 
>> >>. Apologies for missing 
the

>> > docs about tee/replication mode and what you described make sense.
>> >   
>> > Your comment about the matching RD in the BGP messages I think is   
>> > somewhat related to my ultimate goal, which is to enrich the IPFIX   
>> > records with the AS Path using the BGP table for the matching VRF.   
>> > Balancing this with the fact that our routers have limitations in the   
>> > number of addresses to which they will forward IPFIX, my plan was to   
>> > have pmacct in tee mode forward the IPFIX records to a pmacct instance   
>> > dedicated to peering with only one VRF where it could do the BGP lookup.   
>> > Alternative would be 

Re: [pmacct-discussion] nfacctd pretag.map with mpls_vpn_rd

[Andrew Lake]

Hi Paolo,

Thanks for the explanation and talking through this with me. Indeed
flow_to_rd.map was the missing piece I needed. I have things working the
way we wanted by generating a flow_to_rd.map that matches on the router_ip
and mpls_vpn_id. Your SNMP suggestion would also work for us too since we
have all that info readily available, but going the mpls_vpn_id route keeps
the number of entries smaller and should change less. I had previously
played around with flow_to_rd.map but for whatever reason convinced myself
it wasn’t affecting the path lookups. It is very clearly working though
now, no many thanks for your guidance.

>From my perspective issue 770 can also be closed.

Thanks,
Andy

On March 19, 2024 at 4:33:08 AM, Paolo Lucente (pa...@pmacct.net) wrote:


Hi Andy,

Amazing! So probably, after all, we may bash Issue 770 on GitHub -- coolio.

Let me recap situation so that you can correct me where i am wrong and
fill any gaps. You have flows, these (all or some) have a VRFID; you
have BGP feeds and there, obviously, you have MPLS VPN RD. The linking
pin is the flow_to_rd_map (see examples/flow_to_rd.map.example and
CONFIG-KEYS).

The map allows you to work in a few modes: 'id' is the output, the RD as
you want to match it in the BGP feed; you can output the RD in a few
different modes: basing on router / interface, for example; or VRFID; or
the MPLS label stack. Probably you want the VRFID scenario.

Problem that often people come across is .. what is the VRFID anyway,
where do i source the info? Of course some vendor-specific SNMP polling;
so some people i have seen preferring to go to the router / interface
scenario, because if you have some sort of inventory / source of truth
that is easy to compose.

Probably the least popular scenario is composing the map with MPLS
labels but now in the software-defined world, potentially with
controllers, that sporadically happens too.

Paolo


On 19/3/24 05:57, Andrew Lake wrote:
> Hi Paolo,
>
> Ok maybe I have gotten headed down the wrong path. It sounds like you’re
> saying nfacctd in normal collector mode should be able to take into
> account the VRF when asking the BGP daemon to lookup the AS path for a
> flow? This would be my ideal situation, and the replication setup I had
> was just trying to get around the fact that I didn’t think it did based
> on some preliminary testing. I might have given up too soon when it
> didn’t appear to be working though.
>
> Are there any extra options in nfacctd.conf or similar I need to set to
> make it take the VRF into consideration for the path lookup?
>
> What fields does it look at in the BGP message and IPFIX messages to
> make the decision? rd and mpls_vpn_rd respectively? Mainly just asking
> so I can debug if something was not getting set properly by our routers
> in either of the message sets when I was testing.
>
>
> Thanks again,
> Andy
>
> On March 16, 2024 at 1:06:48 AM, Paolo Lucente (pa...@pmacct.net
> ) wrote:
>
>>
>> Hi Andy,
>>
>> Thanks for opening the issue on GitHub and the kind words.
>>
>> Thing is all you want to achieve is supported in pmacct when working in
>> collector mode where the proper inspection of each flow is performed.
>>
>> Why don't you leave the tee part barebone and implement these features
>> in the collector? Just an idea as a perfectly valid answer could be that
>> performing this enrichment in the replicator then also 3rd party tools
>> could benefit from this info. Let me know.
>>
>> Paolo
>>
>>
>> On 16/3/24 01:51, Andrew Lake wrote:
>> > Hi Paolo,
>> >
>> > Thanks for reply! I have created the issue as requested:
>> > https://github.com/pmacct/pmacct/issues/770
>> 
>> > > >. Apologies for missing
the
>> > docs about tee/replication mode and what you described make sense.
>> >
>> > Your comment about the matching RD in the BGP messages I think is
>> > somewhat related to my ultimate goal, which is to enrich the IPFIX
>> > records with the AS Path using the BGP table for the matching VRF.
>> > Balancing this with the fact that our routers have limitations in the
>> > number of addresses to which they will forward IPFIX, my plan was to
>> > have pmacct in tee mode forward the IPFIX records to a pmacct instance
>> > dedicated to peering with only one VRF where it could do the BGP
lookup.
>> > Alternative would be to try to lookup up the path by mapping the IPFIX
>> > VRF ID to the BGP RD and then basing the lookup on that value in
>> > addition to the prefix, but this seems like non-hanging fruit as you
>> > said. if you are able to get the VRF ID matching against IPFIX working
>> > so we can tee it from there, that will be fantastic.
>> >
>> > Thanks again for all your help…and also just in general building an
>> > awesome product :)
>> >
>> > Andy
>> >
>> > On March 15, 2024 at 2:18:01 AM, Paolo Lucente