[rbridge] draft WG minutes
Eric.Gray at marconi.com (Gray, Eric) Wed, 31 August 2005 14:51 UTC
From: "Eric.Gray at marconi.com"
Date: Wed, 31 Aug 2005 10:51:39 -0400
Subject: [rbridge] draft WG minutes
Message-ID: <313680C9A886D511A06000204840E1CF0C885E30@whq-msgusr-02.pit.comms.marconi.com>
Erik, It's "Steve Trowbridge", not "Drawbridge"... The comment ("??") about "missing the obvious" was me. "Dino" is D. Farinacci (for anyone that does not know him). --> -----Original Message----- --> From: rbridge-bounces at postel.org --> [mailto:rbridge-bounces at postel.org]On --> Behalf Of Erik Nordmark --> Sent: Wednesday, August 31, 2005 10:02 AM --> To: Developing a hybrid router/bridge. --> Subject: [rbridge] draft WG minutes --> --> --> --> Any corrections to what was said/discussed/agreed upon? --> --> Erik --> --> --- --> --> TRILL WG Minutes August 4, 2005 --> --> Minutes taken by Alia Atlas. --> --> Agenda: --> --> Deliverables: --> --> Erik Nordmark: "Some fairly tight dates on getting at least --> the problem --> statement and architecture document. This is something the IETF --> wants to see. There was a proposed outline sent around --> that we can --> share with the list. --> --> Requirements for a TRILL-capable routing protocol & --> select existing --> protocols. Work with appropriate routing wg on --> suitability/extensions. --> --> Produce a set of TRILL specs for standards track. --> draft-perlman-rbridge is the start." --> --> Russ White: The extensions to the routing protocols is --> already a work in --> progress - just not published yet. --> --> Erik Nordmark: When that gets published as a draft, will go to the --> list so people can have a look at it. --> --> ==================== --> Coordination with IEEE 802.1: --> --> Donald Eastlake: Quick overview on 802.1 liaison. IEEE 802.1 is --> custodian of the 802 Architecture & defines what it is. --> (See presentation slides) --> --> Bernard Aboba is the overall liaison but there's --> plenty of room for --> more --> specific liaisons. --> --> Paul Congdon: Vice chair for 802.1(??). There is a big --> difference in --> IEEE as well & 802.1 operates more informally than many 802 groups. --> Don't vote on each little thing & operate on consensus. While we do --> have a formal voting process, we do typically accept comments from --> people who aren't part of the WG & I've never seen outside comments --> not processed. 802.1 is much more informal and a relationship with --> TRILL should be straightforward. My questions is when you --> talk about --> the liaison relationship, it wasn't clear what you'd want --> 802.1 to be --> doing explicitly. Obviously, we'll have people attending anyway as --> IETF participants. --> --> Donald: First, I want to agree with what you said about 802.1 being --> more open about comments from outside the WG. In 802.11, which is --> more formal, if there are technical questions, the chair can submit --> them as his own. For the question, the liaisons at a minimum would --> report what was happening & report --> --> Paul: Dorothy is the liaison for most of the wireless, but --> I've been --> serving as liaison for the 802.1 related work & will --> continue to do so. --> --> Steve Drawbridge(??): One of the co-authors on the new IETF liaison --> process. Part involves the IAB appointing an individual to --> look after --> the liaison. Liaison relationship actually means something --> in the IETF --> context. --> --> ==================== --> Problem statement and architecture --> --> Erik: Editor for this draft should be here, but person is --> still TBD. --> Put this up to encourage people on it. Looking for --> a volunteer --> author/editor. --> --> (See presentation) --> --> Richard Spencer: You put a list of what could be considered --> requirements. Can you tell us where those requirements have come --> from? What enterprise customers have said these meet their --> requirements? Have they said that these are the problems that they --> want to be solved & this is the solutions? Are there any enterprise --> customers here that have these problems that need to be solved? --> --> Erik: These things have made it into the charter based on people --> saying they've had these requirements. I think it's hard --> to pinpoint --> the origin of all of these requirements. --> --> Richard: It seems to me that we have a solution & are looking --> requirements. --> --> Erik: We have a charter saying that the rbridge is a start & we --> discussed this during the BOF. --> --> Richard: Are you intending to create a new market for this --> solution. --> --> Erik: Yes. Whatever it said on the first page, shortest-path frame --> routing in multi-hop 802 network. --> --> Richard: If we don't have requirements, how do we know this is the --> best solution? --> --> Erik: I think this is out of scope. --> --> Joe Touch: There are several docs. I've seen WG have as --> many as 8 or --> 10 docs that lead up to the solution; shouldn't do that. --> The doc that --> we have to date is a combo of a problem statement and architecture. --> The problem statement should include the applicability. The --> architecture should also list the requirements. Some of --> those listed --> are architectural requirements, not problem statements. --> Shouldn't be --> that hard to take a first stab at that. Easier to see it from the --> docs; it's hard to do that on the fly. --> --> Erik: If we can get that clarity, I agree. I'm not sure how we're --> going to work on moving forward on describing the problem statement --> and the architecture. --> --> Christian Huitema: I really think we need to work on the --> requirements. When I read these slides, what's missing is --> the ref to --> the wireless networks. I don't know if that was --> deliberate, but it is --> a large area of campus networks. --> --> Erik: Had question in BOF if targeted explicitly at wireless & --> answer was no, but could be useful there. --> --> Christian: I agree but I'm talking about the wireless networks. --> Taking the differences into account makes it likely that --> the solution --> won't be applicable. --> --> Erik: Popping up, during the charter discussion, decided that we --> didn't need a requirements doc first. This is fairly --> solutions driven --> from an architecture perspective. Having a solution in the rbridge --> means that we don't need a year or 2 to write a requirements doc. --> --> Christian: Agree not to spend 2 years arguing about requirements --> first. However, the requirements (or architecture) draft should --> consider the wireless as well. --> --> ?? Jenkins: Share some concerns about the requirements. --> The problem --> statement isn't a problem statement that is to be solved. --> Until I can --> see that, architecture seems a bit premature. --> --> Russ White: The IETF typically doesn't take requirements from --> customers, but from vendors. The vendors I know (Cisco for one) has --> customers who are interested. We have people interested in --> working on --> this & vendors interested in implementing this so we move ahead. On --> 802.11, I think that this will be useful there, but it might be good --> to limit the discussion scope architecture about how this --> works & then --> look at the wireless as we know this is coming next & commit to --> looking at that and working on it, but let's solve what's --> on the table --> first. --> --> Vach Kompella: Speaking as chair of L2VPN, I don't think --> that there's --> enough in the charter that distinguishes this from L2VPN. I think --> that a requirements doc is more necessary than you imagine --> & then make --> that discussion here. We did have a scope discussion about --> work here --> versus L2VPN. I agree with Joe that this could be useful. I don't --> want to get hung up on bureaucracy, but in L2VPN, L3VPN, --> etc. we have --> the customers write the requirements - so I disagree with Russ. Of --> course, we have a smaller set of clueful service providers, --> so I'm not --> saying that we need to go find clueful enterprises. There should be --> some people who will sign on and say that this is a problem & we see --> the issues. --> --> Joe Touch: Usually when you include a problem statement, --> it's bundled --> with the applicability. --> --> Mark Townsley: Could we focus on the problem statement & --> applicability & if this isn't sufficient, then we'll think about a --> requirements doc. They're useful, but not always necessary. Let's --> focus just on the problem statement & applicability inside --> that, which --> might help satisfy Vach's concerns. --> --> Joe: It might also help address the question of who wants this --> problem. --> --> Erik: We did have the question about how this compares to --> L2VPN. We --> did have this in the charter, but took out. I think it --> makes sense in --> explaining this as part of the --> --> ??: I think a lot of people are missing the obvious, if we did a --> survey about how many enterprise customers are in here, --> well everyone --> in here are enterprise customers. --> --> Erik: But if they're building equipment to serve the SP network, are --> they thinking of those or of their own networks? It's --> good b/c this --> helps clarify some of what I've been missing in terms of what the --> problem statement and applicability should talk about. --> --> (More presentation) --> --> Joe Touch: There's a bunch of threats that don't come to mind, such --> as misconfiguration. There's a lot longer list of things under the --> "do no harm". --> --> Erik: Right, there's a lot of robustness concerns that could be --> exploited. --> --> Joe: Even not considered as attackers but rather accidentally. --> --> Erik: Traditionally, we think about active attackers. --> --> Joe: In the architecture, go through both active attackers & --> misconfigurations. --> --> Erik: I'm not sure if the security ADs would agree with --> calling them --> threats. --> --> Joe: Right, but the first do no harm is a lot broader than the text. --> --> Alex Zinin: On scalability, one thing to keep in mind is --> the frequency of --> updates, such as start of the day when things are coming on-line & --> hosts moving around. --> --> Erik: That would be in the applicability. --> --> Alex: Yes, you'd need to define what is the scalability range that --> you're optimizing for. --> --> Erik: I'd like to see this as a concise document? What's missing? --> Looking for volunteers.. --> --> ==================== --> Requirements on routing protocols --> --> Erik: Again, this is a TBD author. Trill will provide a --> requirements --> doc for the routing protocols & then select which to use. Any --> extensions needed to the routing protocol. There's been --> some work & --> an ISIS extensions draft is already underway. --> --> Want to enable 0-touch, so can operate without manual --> configuration. (See presentation) --> --> ==================== --> Protocol document: --> --> Radia Perlman: (see presentation) --> How many spanning trees? --> --> How to learn endnode information? --> --> How to handle multicast --> - IP multicast --> - non-IP multicast --> --> Vach Kompella: How do you know which VLANs belong to which RBridges? --> --> Radia: That would have to be configured. It would be in the --> link-state protocol. Not just "hi I'm Radia, but also these are my --> VLANs". --> --> Alex Zinin: From my understanding, the bridges that announce their --> VLAN membership is just the RBridges connected to the end-hosts. --> --> Radia: All the RBridges support traffic transport. --> --> Alex: So how do you decide where to forward? --> --> Radia: Calculate a spanning tree (assume one) & you're not in any --> VLANs. Look downstream to see which VLANs are connected to the --> RBridges. (Continuing presentation showing why one might want --> separate spanning trees per VLAN). --> --> Dino: Might want to say what a per-VLAN spanning tree would be used --> versus a global spanning tree. --> --> (More presentation) --> --> Erik: A question on the dynamic nature of this, through --> 802.11x, this --> might attach to a particular access point. Hosts could move & VLANs --> might come & go on RBridges. --> --> Radia: yeah --> --> Alex: One comment on spanning tree calculation. Suggested just --> selecting the lowest router ID. One problem is that that --> router might --> be momentarily unavailable or frequently. --> --> Radia: If we're doing a tree per RBridge, not a problem. --> --> Alex: Yes, but for a single spanning tree, it would be. The draft --> has some words for ECMP-tie breakers. You really need to --> worry about --> bundles between nodes. --> --> Radia: It depends if those links are transparent to the rest of the --> world. If not, we'd need a deterministic tie-breaker, so --> would need to --> include the port ID as well as the router ID. --> --> (Second presentation) --> --> Michael Smith: Quick question. The recommendation is to still pass --> the MAC addresses --> --> Radia: Yes, but just passing around & not need to store them if not --> part of the same VLAN. --> --> Michael: I was quite encouraged by the second approach where you do --> the learning. --> --> Radia: Yes, this is something which is better suited to --> discussion on --> the mailing list. --> --> Erik: It would be useful to write up an email to see the pros and --> cons on the possibilities. --> --> Radia: Yes, and if sufficiently long, might be a draft. --> --> Alex: Before we start discussing the pros and cons, having the --> possible solutions fully described would help. --> --> (Third presentation) --> --> Tim Shepherd: Are we concerned about defending against denial of --> service attacks? --> --> Radia: We certainly could say that there's a certain percentage of --> traffic that's available to multicast - but that's orthogonal. --> --> Tim: But earlier, for unicast, if one hasn't heard of the address, --> then it is broadcast. --> --> Radia: That's the case today... --> --> Tim: If this tech allows larger domains without routers, could DoS --> whole domain... --> --> Erik: Would be interesting to understand if people understand with --> snooping if there are things delivered without the IGMP. ??? --> --> Dino: They default to dropping, if IGMP snooping is --> configured on all --> switches, if the MAC is IP-derived. --> --> Erik: There are 2 different behaviors depending on if the MAC is --> IP-derived. --> --> (presentation continues) --> --> Dino: IGMP forwarding doesn't happen for that case. --> Existing snooping --> IGMP bridges don't have this problem. --> --> Radia: We need to make sure they don't. We haven't written down the --> design yet, so just need to make sure that we don't break that. It --> could be that we just copy the design for IGMP snooping --> bridges, or we --> may need to do more. --> --> Radia: Should we allow cross-VLAN delivery of IP multicast? --> --> Alex Zinin: That's a router function; I'd leave it alone. --> I think we --> should preserve the functionality that is there. --> --> Radia: This is something else we should discuss on the list. --> --> Erik: What happens when you have a mixture of bridges and RBridges? --> What happens when some bridges do IGMP snooping & some don't? --> --> Dino??: There's nothing standardized, but MAGMA has --> something written --> down talking about how not to break it. --> --> Dino??: If the RBridges don't do the IGMP snooping & the --> existing bridges --> do, how does that work? --> --> Erik: On the cross-VLAN thing, people may deploy VLANs for different --> reasons. Some may be for security & some may be to limit the --> broadcast domain. This --> --> ???: When we talk about non-IP multicast, we need to consider MPLS --> multicast. --> --> Erik: They're specifying multicast in MPLS, but --> --> Alex: As a general response, let's leave MPLS multicast for later. --> It's not yet a done deal & it won't be as easy as IP multicast. --> --> Dino: I think we'll have a struggle between management isolation & --> optimization. Then, do you want to support both or just make a --> decision? --> --> Alex: We could limit it to L2 as part of this & then some --> nodes could --> do it as part of their L3 functionality. --> --> ????: Are you considering something like MSDP like --> multiple spanning --> trees per VLANs. --> --> Radia: If you're doing per-RBridge spanning trees, then don't need --> for per-VLAN. Then which VLAN it is is only filtering --> information per --> port. --> --> ????: Assume a bridge that is doing IGMP snooping, how will --> the bridge --> in the middle be able to interoperate since we're adding a header. --> --> Radia: That's a question. Since this isn't written down, --> we need to --> get the design correct. It'd be good if we had people on --> the list who --> really understood how IGMP bridge snooping really worked. --> --> ????: What about MTU issues? Have we thought about those? --> --> Radia: For a few years, I always assumed that adding a few bytes --> would be fatal, but now they're doing VLAN tags and MAC-in-MAC so --> apparently it's not a problem. --> --> Erik: So at end of the agenda, should we accept this --> rbridge doc as a --> WG doc... Are we ready to answer the question? --> --> Loa: This doc is actually mentioned as the starting point in the --> charter, so is there a question. --> --> Joe Touch: It might be more productive to offer to start with --> breaking the document into two pieces. One that looks more like an --> applicability and one that looks like an architecture... --> --> Erik: The only reason to ask the question now is to rename --> the doc so --> it's easier to find. Second step is figuring out which --> docs we need. --> --> Paul: It does seem a bit odd to adopt a protocol doc --> before you even --> have other docs written or even outlined. It makes sense that it --> would be a WG doc at some point, but not sure whether the WG will --> consider other approaches. --> --> Erik: The IESG re-wrote it into the charter. The document will --> definitely evolve; it's a starting point. --> --> ?????: What we have here is a doc that we clearly think will be --> broken up. 2 revs down the road, it'll clearly go away. --> Sounds to me --> like at least 3 (apps, arch, protocol). Once those are --> spun out, then --> we can talk about adopting them. --> --> Vach Kompella: It also seems odd to have this in the --> charter... You --> need at least one rev of the charter now, to take this out. --> --> --- --> _______________________________________________ --> rbridge mailing list --> rbridge at postel.org --> http://www.postel.org/mailman/listinfo/rbridge -->
- [rbridge] draft WG minutes Erik Nordmark
- [rbridge] draft WG minutes Gray, Eric
- [rbridge] draft WG minutes Vishwas Manral