Re: [bess] Query/comments on draft-ietf-bess-evpn-lsp-ping-05

["Parag Jain (paragj)" <[e-mail]>]

Hi Saumya

Pls see inline.

From: "Dikshit, Saumya" <[e-mail]>
Date: Tuesday, September 7, 2021 at 3:22 PM
To: "Parag Jain (paragj)" <[e-mail]>om>, "[e-mail]" <[e-mail]>rg>, "[e-mail]" <[e-mail]>
Cc: "[e-mail]" <[e-mail]>
Subject: RE: Query/comments on draft-ietf-bess-evpn-lsp-ping-05

Hi Parag,

Thanks for the response. I have few bullets on the same.
Please help clarify and if there is a need to call them out explicitly.


  1.  “Consistency checkers” feature-set does validates the CP-DP parity and can be leveraged via management interface to the box.
     *   Do you imply the consistency check between protocol RIB and the dataplane FIB, Or the consistency between Software FIB (slow path) and the LC-FIB
Paragj> CP would mean BGP/EVPN/RIB which ever CP component has the info included in the sub-TLVs.


  1.  Parameters such as RD, shall not make it to the DP and their presence is restricted to the NLRI (entries/tables) in the protocol RIB.
     *   In case the RIB specific parameters need validation, then on receive side processing of ping, should run it through the RIB and FIB both ?
Paragj> yes.

     *   In case it’s just the dataplane validation (which I can gather from this draft), then RIB validation is not required and RD’s  can carry “don’t care”.
  1.  If a need be, to perform “reachability-check to a tenant vrf (EVI) on remote NVE”, for which no route has been published yet ?
Paragj> only vrf-existence is not checked by lsp ping.

Thanks
Parag

as I mentioned in #2 of below email

     *   Is it possible to achieve that with lsp-ping check with existing sub-TLVs without “wild-card/don’t-care”

Thanks
Saumya.

From: Parag Jain (paragj) [mailto:[e-mail]]
Sent: Tuesday, September 7, 2021 11:56 PM
To: Dikshit, Saumya <[e-mail]>om>; [e-mail]; [e-mail]
Cc: [e-mail]
Subject: Re: Query/comments on draft-ietf-bess-evpn-lsp-ping-05

Hi Saumya

The remote PE router processing the lsp ping packet, does consistency checks between data plane and control plane. RD, ESI fields along with other fields defined in the sub-tlvs are used for that purpose. Wildcard/don’t care values for these fields will defeat the purpose of DP-CP consistency checks.

Thanks
Parag

From: "Dikshit, Saumya" <[e-mail]<mailto:[e-mail]>>
Date: Thursday, September 2, 2021 at 1:42 PM
To: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Cc: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: Query/comments on draft-ietf-bess-evpn-lsp-ping-05
Resent-From: <[e-mail]<mailto:[e-mail]>>
Resent-To: <[e-mail]<mailto:[e-mail]>>, <[e-mail]<mailto:[e-mail]>>, <[e-mail]<mailto:[e-mail]>>, <[e-mail]<mailto:[e-mail]>>, <[e-mail]<mailto:[e-mail]>>
Resent-Date: Thursday, September 2, 2021 at 1:42 PM

[sending the queries in a different email with changed subject line]

Hello Authors of draft-ietf-bess-evpn-lsp-ping draft,

I have following queries regarding this draft:

>>>> Do we intend-to-use/call-out-usage-of “wild-card/don’t-care” values for attributes carried in the sub-TLVs ?
For example, If the admin intends  to check the reachability to host (MAC_X/IP_X) published (in route-type-2)  by remote PE.
The remote PE learnt it locally over ESI_X against Vlan X (mapped to BD_XYZ).

Is it possible, that the “EVPN MAC sub-tlv”  can carry the “Route Distinguisher” and “Ethernet Segment Identifier” as don’t care.

>>>> Another caseto handle would be test the reachability to tenant-VRF VRF_X (with EVPN mapped EVI) configured on the remote PE, PE1.
VRF_X has no active IP/IPv6 interface configured and its sole usage is to obtain the leaked (via IVRL) routes from other VRFs (non-EVPN) and PE1 published this to other peers via EVPN control plane. Till the first prefix (learnt ) route is published (Route Type 5) by PE1 for the EVI (mapped to VRF_X), the tunnels will not be provisioned on other PEs.
In order to test the reachability to VRF_X (on PE1) from another PEs, let’s say, PE2 or a centralized-controller (which can emulate/supports MPLS),

It may need to carry all/subset-of attributes with “don’t-care/wild-card” in “EVPN IP Prefix Sub-TLV”.


Please let know your thoughts on above.

Thanks
Saumya.