Hello Shahram,
  As Santosh mentions below, a revision of this draft will be published shortly 
mandating the use of a valid inner Destination IP address in the packet.
Thanks
Prasad

-----Original Message-----
From: Santosh P K [mailto:[email protected]] 
Sent: Tuesday, June 30, 2015 2:43 PM
To: Shahram Davari; Gregory Mirsky; Vengada Prasad Govindan (venggovi)
Cc: [email protected]
Subject: RE: New Version Notification for draft-spallagatti-bfd-vxlan-00.txt

 
> Another question I have is how do you forward these BFD packets from 
> VTEP to VM? Since DIP = 127/8, I assume there is no way to forward 
> such packets past the VTEP.

We don't want to send it past VTEP as BFD will terminate at VTEP itself. Right 
now use of 127/8 is not really clear as inner IP address. We have again added 
some text for inner IP address and its use. 


> 
> If you want to do VM to VM connectivity check then I suggest one of 
> the
> following:
> 
> 1) if VMs are only L2 aware and VXLAN is L2VPN, the run Ethernet OAM 
> between VMs
> 2) If VMs are L2 and L3 aware and VXLAN is L2VPN then run BFD over 
> IP/UDP over Ethernet over VXLAN
> 3) If VMs are L3 aware and VXLAN is L3VPN then you have 2 cases:
>           3a) If VTEP and VMs are physically  in the same CPU core 
> then run what you are proposing in this draft (1-hop BFD). Although it 
> should give you same result as running BFD over the outer IP tunnel
>           3b) If VTEP and VMs are physically separate (such as VTEP is 
> in TOR and VM is CPU core), then run something similar to what you are 
> proposing but with Multi-hop DIP address so that BFD can be forwarded to VM 
> from VTEP.
> 

We are not trying to address VM to VM connectivity check as I believe that does 
not really need any changes and BFD as it is should run. Proposal is from VTEP 
to VTEP.


Thanks
Santosh P K 

> -----Original Message-----
> From: Rtg-bfd [mailto:[email protected]] On Behalf Of Shahram 
> Davari
> Sent: Monday, June 29, 2015 4:15 PM
> To: Gregory Mirsky; Vengada Prasad Govindan (venggovi)
> Cc: [email protected]
> Subject: RE: New Version Notification for 
> draft-spallagatti-bfd-vxlan-00.txt
> 
> Hi Greg,
> 
> I don't see much value in running BFD for SS-PW compared to running 
> BFD over the LSP.
> 
> Thx
> SD
> 
> -----Original Message-----
> From: Gregory Mirsky [mailto:[email protected]]
> Sent: Monday, June 29, 2015 2:21 PM
> To: Shahram Davari; Vengada Prasad Govindan (venggovi)
> Cc: MALLIK MUDIGONDA (mmudigon); Santosh P K; [email protected]
> Subject: RE: New Version Notification for 
> draft-spallagatti-bfd-vxlan-00.txt
> 
> Hi Shahram,
> I'll get to VXLAN shorty but wanted to ask quick question about SS-PW. 
> True, we have case of MS-PW where PW label used (that was discussed in 
> MPLS- TP in particular). But that doesn't mean that VCCV BFD has value 
> only for MS- PW and for SS-PW has no value. Would you agree?
> 
>       Regards,
>               Greg
> 
> -----Original Message-----
> From: Shahram Davari [mailto:[email protected]]
> Sent: Monday, June 29, 2015 2:02 PM
> To: Gregory Mirsky; Vengada Prasad Govindan (venggovi)
> Cc: MALLIK MUDIGONDA (mmudigon); Santosh P K; [email protected]
> Subject: RE: New Version Notification for 
> draft-spallagatti-bfd-vxlan-00.txt
> 
> Hi Greg,
> 
> You are welcome. Could you please clarify which one of the following 
> is the packet format:
> 
> 1) OuterL2-Outer IP-UDP-VXLAN-Inner L2-Inner IP-UDP-BFD
> 
> Or
> 
> 2) OuterL2-Outer IP-UDP-VXLAN-Inner IP-UDP-BFD
> 
> If (2) hen how do you specify the VXLAN payload in IP and not Ethernet?
> 
> Also This is different from PW BFD, since in case of PW, there can be 
> MS-PW, where the LSP BFD is not end-to-end. But in this case we don't 
> have MS- VXLAN.
> So the span of the VXLAN and the IP tunnel is the same.
> 
> In other words you have to specify in which part of forwarding the BFD 
> the VXLAN Tag is used. If it is not used then it has no effect.
> 
> Thx
> Shahram
> 
> -----Original Message-----
> From: Gregory Mirsky [mailto:[email protected]]
> Sent: Monday, June 29, 2015 1:51 PM
> To: Shahram Davari; Vengada Prasad Govindan (venggovi)
> Cc: MALLIK MUDIGONDA (mmudigon); Santosh P K; [email protected]
> Subject: RE: New Version Notification for 
> draft-spallagatti-bfd-vxlan-00.txt
> 
> Hi Shahram,
> thank you for your comments to this proposal that make the discussion 
> so much alive.
> I think that processing of the VXLAN tag by VTEP before validating BFD 
> is sufficient, in my view, level of verification. In VCCV BFD the PW 
> label is not used for BFD forwarding but we find it useful as Service 
> OAM in addition to RFC 5884, BFD over MPLS LSP.
> 
>       Regards,
>               Greg
> 
> -----Original Message-----
> From: Shahram Davari [mailto:[email protected]]
> Sent: Monday, June 29, 2015 10:39 AM
> To: Vengada Prasad Govindan (venggovi)
> Cc: Gregory Mirsky; MALLIK MUDIGONDA (mmudigon); Santosh P K; rtg- 
> [email protected]
> Subject: RE: New Version Notification for 
> draft-spallagatti-bfd-vxlan-00.txt
> 
> Hi Prasad,
> 
> Is this a special type of BFD or standard BFD RFC 5880 and 5881)? 
> Since standard BFD processing does no care where the BFD came from it 
> only looks at "your discriminator" to update BFD state machine.
> 
> Also I don't see how many VXLANs can be checked via a single BFD session.
> Could you please describe?
> 
> Lastly checking to see a VXLAN/VNI forwarding domain exist in a VTEP 
> should not require BFD. Just use some query mechanism. Why do you need 
> to run continuous BFD.
> 
> What you have to show me to convince me that your draft solves a real 
> problem is to show that VXLAN tag  is  used for BFD forwarding. 
> Otherwise BFD over the outer or Inner IP should give you all coverage needed.
> 
> 
> Thx
> Shahram
> 
> 
> 
> 
> -----Original Message-----
> From: Vengada Prasad Govindan (venggovi) [mailto:[email protected]]
> Sent: Monday, June 29, 2015 3:11 AM
> To: Shahram Davari
> Cc: Gregory Mirsky; MALLIK MUDIGONDA (mmudigon); Santosh P K; rtg- 
> [email protected]
> Subject: RE: New Version Notification for 
> draft-spallagatti-bfd-vxlan-00.txt
> 
> Hello Shahram,
>   At the terminating VTEP, VxLAN information is used to consume the 
> BFD packet. In other words, a BFD session increases the confidence of 
> the existence of the VNI-Forwarding Domain mapping and the presence of 
> valid VTEP termination configuration at the terminating VTEP. At the 
> originating VTEP, it is a matter of implementation of how many VxLAN 
> tables are exercised in the datapath (am aware of at least one 
> implementation where it is being exercised to a considerable extent).
> 
> Thanks
> Prasad
> 
> -----Original Message-----
> From: Shahram Davari [mailto:[email protected]]
> Sent: Saturday, June 27, 2015 8:24 PM
> To: Shahram Davari
> Cc: Vengada Prasad Govindan (venggovi); Gregory Mirsky; MALLIK 
> MUDIGONDA (mmudigon); Santosh P K; [email protected]
> Subject: Re: New Version Notification for 
> draft-spallagatti-bfd-vxlan-00.txt
> 
> Hi
> 
> May be a better way to make this clear is to answer the following question:
> 
> Where is the VXLAN tag information used in this BFD forwarding?
> 
> Thx
> Shahram

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