Hi Shunwan,

That’s a good point. A couple of comments about it and why I think we
should use a length = 48.

- I don’t know about draft-bonica, but there is already at least one
shipping implementation using 00:..:00/48 as per
draft-rabadan-l2vpn-dci-evpn-overlay
- There are a few reasons why we decided to use length 48:

1) The EVPN base draft only allows a MAC length = 48 and says other length
is out of scope
2) In the IP world, there is subneting so a default route with length /0
makes sense. In the MAC world, there is no subnetting (at least in real
implementations where MACs are not managed) so some implementations might
have issues with lengths different than 48.
3) the meaning of 00:..:00/48 is a bit different than only a default
route. We actually decided to call it “unknown mac route” since you might
want to advertise it from different gateway devices to attract all the
unknown traffic to ONLY those devices. In
draft-rabadan-l2vpn-dci-evpn-overlay you can see that the ingress PE needs
to send unknown traffic to all the egress PEs advertising the
unknown-mac-route, as opposed to only one.

Thank you.
Jorge

-----Original Message-----
From: Zhuangshunwan <[email protected]>
Date: Wednesday, July 2, 2014 at 1:00 AM
To: 'Thomas Morin' <[email protected]>, "[email protected]"
<[email protected]>
Cc: "[email protected]" <[email protected]>,
"[email protected]"
<[email protected]>
Subject: About ALL-ZERO-MAC's encapsulation in EVPN MAC/IP Advertisement
route. //Re: Poll for adoption: draft-bonica-l3vpn-orf-covering-prefixes

>Dear all,
>
>I have got into knots for presentment of ALL-ZERO-MAC's encapsulation in
>EVPN MAC/IP Advertisement route.
>
>draft-bonica-l3vpn-orf-covering-prefixes-03 defines the "Default MAC
>Route ":
>
>   o  Default MAC Route (DMR) - An EVPN MAC/IP Advertisement Route with
>      MAC Address length equal to 0.
>
>But draft-rabadan-l2vpn-dci-evpn-overlay-01 said:
>
>2.5.1 Use of the Unknown MAC route to reduce unknown flooding
>
>      The solution suggested in this document is based on the use of an
>      "Unknown MAC route" that is advertised by the Designated Forwarder
>      DC GW. The Unknown MAC route is a regular EVPN MAC/IP
>      Advertisement route where the MAC Address Length is set to 48 and
>      the MAC address to 00:00:00:00:00:00 (IP length is set to 0).
>
>
>Can we use a uniform way?
>
>
>Regards,
>Shunwan (Vincent)
>
>-----邮件原件-----
>发件人: L3VPN [mailto:[email protected]] 代表 Thomas Morin
>发送时间: 2014年6月27日 22:21
>收件人: [email protected]
>抄送: [email protected]
>主题: Poll for adoption: draft-bonica-l3vpn-orf-covering-prefixes
>
>Hello working group,
>
>This email starts a two-week poll on adopting
>draft-bonica-l3vpn-orf-covering-prefixes-03 [1] as a working group item.
>
>Please send comments to the list and state if you support adoption or
>not (in the later case, please also state the reasons).
>
>This poll runs until July 12th.
>
>
>*Coincidentally*, we are also polling for knowledge of any IPR that
>applies to this draft, to ensure that IPR has been disclosed in
>compliance with IETF IPR rules (see RFCs 3979, 4879, 3669
>and 5378 for more details).
>
>==> *If you are listed as a document author or contributor* please
>respond to this email and indicate whether or not you are aware of any
>relevant IPR.
>
>The draft will not be adopted until a response has been received from
>each author and contributor.
>
>If you are on the L3VPN WG mailing list but are not listed as an author
>or contributor, then please explicitly respond only if you are aware of
>any IPR that has not yet been disclosed in conformance with IETF rules.
>
>Thank you,
>
>Martin & Thomas
>l3vpn chairs
>
>[1] http://tools.ietf.org/html/draft-bonica-l3vpn-orf-covering-prefixes-03
>

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