I think the best way to phrase it is “static MAC ACL” applied to all member ports. There could be reasons to do static MAC entries in the forwarding table (so traffic does not flood when a large link drops) but we are not talking about that here/yet.
From: MICE Discuss [mailto:[log in to unmask]] On Behalf Of Steve Howard
Sent: Monday, October 31, 2022 8:59 AM
To: [log in to unmask]
Subject: Re: [MICE-DISCUSS] Proposal: MICE Static MAC address Only
Below is a message indicating the current policy as decided by the MICE Board in December 2019 is that the MAC address limit is 1.
The subject of Jay's message indicates "Static" MAC, but, the text seems to indicate a limit of 1. I like the 1 address limit, but, am not a fan of Static. Was the current issue caused by somebody not having a proper MAC address limit installed?
On 12/13/19 18:00, Richard Laager wrote:
The board has approved the change in MAC address limit from 5 to 1. NOTE: This is orthogonal to the dedicated remote switch question, whichis still pending. Non-dedicated remote switches can, for example,enforce this per-VLAN. We have already confirmed that most participants are using only 1 MACaddress, and some that were using more than 1 have addressed that afterbeing contacted. As discussed below, this change will be rolled out in away to keep everyone working, by grandfathering if necessary. On 10/28/19 3:25 PM, Richard Laager wrote:
We have discussed this a bit in the past, and this came up at the lastUG. I'm looking for feedback from the group before formally proposingthis to the board for a vote. I first brought this up to the technical committee, CCing the board. Ihave heard no objections. Jeremy is "in favor of it 100%". Based on our quick conversation after the UG, I _think_ Anthony is infavor as well; we both made notes to follow up on this. ----- I am proposing that MICE change its MAC address limit from 5 MACs perport to 1 MAC per port. 1 MAC address is enough for normal scenarios andthis would further limit the potential for problems on the fabric. Thisrestriction is one that SIX and AMS-IX both have, with the latter beingknown for their excellent configuration guide for participants:https://www.ams-ix.net/ams/documentation/config-guide To be clear, this is still only for end ports, not ports facing remoteswitches, of course. The remote switches are responsible for enforcingthe current MAC limit, and would be responsible for changing thosesettings as described here. If someone is swapping their MICE-facing router, the resulting port flapon the MICE/remote switch will clear the limit anyway, if they aredirectly connected. If they are unable to flap the port (e.g. becausethey have someone else's layer 2 gear in the middle), they will have toeither work with that carrier or their switch operator (MICE/remote) toflap the port. This is a non-zero burden, but I think it's prettyminimal in practice. Additionally, if someone plans to make an equipmentswap, we would increase the limit in advance, temporarily, upon request. For reference, SIX goes further and locks you to a particular MACaddress in an ACL, so you have to contact them to change your MAC. I amnot proposing that. Still, I've been through that a couple of times, andeven that isn't really too big of a deal. So I don't think the change toa limit of 1 MAC at MICE will be particularly onerous. There are a couple of participants who have two IP address sets (oneIPv4 and one IPv6) on the same port. For those ports, the limitobviously must be at least 2 MACs, but I propose 3 MACs as the limit. Ifthey're using two IPs, they probably are doing so to get some redundancyout of it. For this particular use case, needing to flap the portdefeats that redundancy goal, as it breaks the other router. Having aMAC limit of 3 would allow them to swap a device without needing to flapthe port. We would grandfather these setups until they are looking for aport-type upgrade; at that point they would need to get to one IPaddress set per port (by splitting into two ports or reducing to one IPaddress set) or request an exception as outlined below. The exceptionprocess would allow us to better evaluate this use case at that time. There are some members who have multiple MACs showing up now, despiteusing only one device. For those, I am proposing we set the MAC limit tohowever many MACs are currently showing up on their port. That is, theywould be grandfathered at their current situation for now. At the timeof this change, we would encourage them to investigate and fix themultiple MACs issue at their leisure. In the future, if they are doing aequipment swap (especially like-for-like), we would again encourage themto address it, but would otherwise leave their higher limit in place. Ifthey do a port-type upgrade, we would not bring the grandfathering over.If they needed, they could ask for an official exception at that time. There may be cases where people cannot reasonably fix their routers touse only 1 MAC, other scenarios I haven't considered, or things that maycome up in the future. For that reason, I think we should allow for thepossibility of exceptions upon request to the board. In practice, Iwould expect the board would confer with the technical committee and/orthe technical committee would be bringing these to the board anyway. Thegoal is to strike a reasonable balance between protecting the fabricwithout preventing networks from connecting.
On 10/31/22 08:27, Jay Hanke wrote:
I propose we change the MICE required port security settings to behard filtered for a single static mac address per port. Over the years, we've had several incidents where floods have occurredprior to port being error-disabled during a looping event.
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