Re: [IPv6] Thoughts on draft-thubert-6man-ipv6-over-wireless-15

["Joe Clarke (jclarke)" <[e-mail]>]

On a different note, but probably of interest for ops, RFC 8929 provides both a routing and a bridging proxy variation. In routing proxy, the BBR answers NSs on behalf of the registered nodes with its own link layer address, and it installs a /128 route towards the registering node. IOW it routes the packets . This is required when the node is, say, on an IEEE 802.15.4 link that has non-bridgeable MACs. But that could be very cool for ops as well as the wireless MACs do not need to show on the backbone, at least for IPv6 operations. Conversely, the bridging proxy lets the registering node answer the NAs (unless the BBR is a sleep proxy of sorts),  meaning that the data packets are bridged by the AP as usual. The broadcasts NS are turned to unicast on the wireless hop, which makes it both faster and reliable, so there’s a clean win there.

JMC: Indeed.  And we aren’t as concerned about the wire so much (though others may be).

The bridging proxy operation is probably the one that the .11 people had in mind but in the end, it is up to the ops people to use either one. The RAs can still be generated by the real routers though the RS could be turn to unicast by the 6BBR, or at least not copied on the wireless side. I hope this helps alleviate the concerns about layer violations. They are limited, required (by .11), and better understood now that we made them a standard vs the art of existing but proprietary variations.

JMC: I like the flexibility.  I can see the IETF NOC crew wanting more of a bridge on the AP/WLC such that routing is left to the routers (at least initially), but more and more we see the attractiveness of decentralizing some of the routing.  Ultimately, seeing a standards approach instead of today’s Magick is very appealing.

JMC: That said, and this is outside the scope of what I typically see in the IETF, vendors are still left to implement the visibility into such standardized flows as they see fit (i.e., think logging and debugging).  Everything is great when the proxy shows the STA is registered.  When the proxy isn’t doing what one thinks it should, it can still be as bad as a proprietary solution to understand why</rant>.

Joe

All the best,

Pascal
From: ipv6 <[e-mail]> On Behalf Of Joe Clarke (jclarke)
Sent: Wednesday, August 2, 2023 8:10 PM
To: [e-mail]
Subject: [IPv6] Thoughts on draft-thubert-6man-ipv6-over-wireless-15

I had a chance to read through this draft with the hat of an IETF NOC member.  Given the number of wireless (and IPv6 wireless) issues we’ve seen over the years, Sections 2.1 and 2.2 really speaks to me.  We have seen issues with failing stateful proxies, incomplete learning of IPv6 addresses, and snooping holes.  These have led to extended onboarding time for IPv6-only clients and times when certain clients can pass traffic.  Things have gotten better, but it’s still a moving target.  This is a real problem, and I’m glad focus is being given to it.

While not IPv6-specific, the IETF conference network currently uses public IPv4 addresses without a firewall (to provide an “Open Internet™”), and this leads to other operational challenges that have required us to use ARP proxies to tamp down the broadcast onslaught.  Not having standards means to do some of these functions has been challenging.

Therefore, I support the spirit of this draft in that a more proactive approach to address registration and use of standardized means to do so and query the registrar would aid in overall network operation..

The concern I have is turning the AP into a BBR.  I can already hear some of the conversations in the NOC about this “layer violation”.  That said, I can imagine a case where AP suppresses the multicast over the air and redirects RS or NS requests directly to the registrar (e.g., campus router).  As you mention, the true wired side of the network is not as susceptible to the shortcomings of NBMA, so pushing this traffic out onto the wire is not such a bad thing, plus it gives less “Magick” for the AP to handle.

Joe