Re: [bess] Question on ARP probe in draft-ietf-bess-evpn-inter-subnet-forwarding

[Muthu Arul Mozhi Perumal <[e-mail]>]

Please see inline..

On Fri, May 3, 2019 at 12:02 PM Rabadan, Jorge (Nokia - US/Mountain View) <
[e-mail]> wrote:

> You only need the IP-VRF RT in case of the IP is included in the MAC/IP
> route _*and*_ you are in symmetric mode, since you need to install the IP
> in the route-table.
>

If we follow the argument that there is only one IP-VRF per BD which you
can identify based on the RT for the MAC-VRF and Ethernet  tag, you don't
need the RT for the IP-VRF even if the MAC/IP route includes the IP and you
are in symmetric mode, right?


> The mobility section is done for both symmetric and asymmetric modes, and
> also, in particular, that case you allude to, there is only a MAC in the
> route that the source NVE receives. So you cannot guarantee the source NVE
> will receive an RT for the IP-VRF.
>

Agree. But, neither section 4.2 nor anywhere else
in draft-ietf-bess-evpn-inter-subnet-forwarding we describe how the source
NVE deduces the IP-VRF when the MAC/IP route has only the MAC address and
MAC-VRF RT.

Regards,
Muthu


>
>
> Thx
>
> Jorge
>
>
>
> *From: *Muthu Arul Mozhi Perumal <[e-mail]>
> *Date: *Friday, May 3, 2019 at 7:39 AM
> *To: *"Rabadan, Jorge (Nokia - US/Mountain View)" <[e-mail]
> >
> *Cc: *"[e-mail]" <[e-mail]>
> *Subject: *Re: [bess] Question on ARP probe in
> draft-ietf-bess-evpn-inter-subnet-forwarding
>
>
>
> Hi Jorge,
>
>
>
> Thanks for your response. Please see inline..
>
>
>
> On Tue, Apr 30, 2019 at 8:43 PM Rabadan, Jorge (Nokia - US/Mountain View) <
> [e-mail]> wrote:
>
> Muthu,
>
>
>
> The source NVE identifies the MAC-VRF/BD out of the RT/eth-tag. The
> assumption is that the BD is only attached to one IP-VRF, hence you know
> what ARP table to look up.
>
>
>
> If this is the case, why include the RT for the IP-VRF at all in route
> type-2 advertisements?
>
>
>
> Regards,
>
> Muthu
>
>
>
> My two cents.
>
>
>
> Jorge
>
>
>
> *From: *BESS <[e-mail]> on behalf of Muthu Arul Mozhi
> Perumal <[e-mail]>
> *Date: *Tuesday, April 30, 2019 at 4:39 AM
> *To: *"[e-mail]" <[e-mail]>
> *Subject: *[bess] Question on ARP probe in
> draft-ietf-bess-evpn-inter-subnet-forwarding
>
>
>
> Hi Everyone,
>
>
>
> draft-ietf-bess-evpn-inter-subnet-forwarding describes the mobility
> procedure to be followed when a TS moves from a source NVE to a target NVE
> and starts sending data traffic without first initiating an ARP request. It
> says the following in section 4.2:
>
>
>
> <snip>
>
>    - The source NVE upon receiving this MAC/IP advertisement, realizes
>
>    that the MAC has moved to the new NVE. It updates its MAC-VRF table
>
>    accordingly by updating the adjacency information for that MAC
>
>    address to point to the target NVE and withdraws its EVPN MAC/IP
>
>    route that has only the MAC address (if it has advertised such route
>
>    previously). Furthermore, *it searches its ARP table for this MAC and*
>
>    *sends an ARP probe for this <MAC,IP> pair*. The ARP request message is
>
>    sent both locally to all attached TSes in that subnet as well as it
>
>    is sent to other NVEs participating in that subnet including the
>
>    target NVE.
>
> </snip>
>
>
>
> The question I have is, the MAC/IP Advertisement route the source NVE
> receives from the target NVE in the above case has only the MAC address of
> the TS and the RT corresponding to the MAC-VRF. How can the source NVE
> deduce the IP-VRF to search the corresponding ARP table and send an ARP
> probe?
>
>
>
> Regards,
>
> Muthu
>
>