Re: [irs-discuss] Thoughts on draft-ward-irs-framework
Susan Hares <susan.hares@huawei.com> Wed, 01 August 2012 19:40 UTC
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From: Susan Hares <susan.hares@huawei.com>
To: Russ White <russw@riw.us>, "irs-discuss@ietf.org" <irs-discuss@ietf.org>
Thread-Topic: [irs-discuss] Thoughts on draft-ward-irs-framework
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Date: Wed, 01 Aug 2012 19:38:00 +0000
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Subject: Re: [irs-discuss] Thoughts on draft-ward-irs-framework
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Russ: -----Original Message----- From: irs-discuss-bounces@ietf.org [mailto:irs-discuss-bounces@ietf.org] On Behalf Of Russ White Sent: Tuesday, July 31, 2012 5:42 PM To: irs-discuss@ietf.org Subject: [irs-discuss] Thoughts on draft-ward-irs-framework This framework is well put together, but I'd like to make a couple of suggestions/comments/put some ideas forward. 1. I think the draft struggles somewhat with describing something that's already in all routers today because it's attempting to describe an interface into the RIB that's somehow separate, or stands beside, the existing interfaces into the RIB. I would gently suggest that describing this entire idea as an "off board routing process," much like a BGP process on an existing implementation, might clarify things a bit, and make the model easier to understand. Consider --any given routing process already installs routes into the routing table, including the concept of preference. BGP routing processes, specifically, also have import and export capabilities into various VRFs. All routing processes also have redistribution capabilities. What if you modeled this entire thing as two types of "off board routing processes," one that only imports data from the RIB for northbound consumption (topology information), and one that interacts with the RIB like any other routing process would for southbound control as well as northbound consumption? ----> [Russ]: +1 - This Offboard controller processing aligns with the ONF view of SDN. And it has been done in practice for 10+ years. However as you know, the timing between the calculation and download to HW is important. It's going to be much easier to interact with the other routing protocols on the box without a lot of "special pleading" if IRS is a process that's peer to BGP, OSPF, IS-IS, et al. Take the instance of link down notifications --all the implementations I know of process link downs in the RIB, and the RIB then notifies the routing protocol... If you're hooking into the RIB locally, then, you need to hook into link down detection specifically and intentionally. If IRS is a routing process, the RIB will notify the northbound interface as a matter of course in processing link down notifications. I hope that makes sense, but I'm glad to sit and discuss if it doesn't. 2. There needs to be a way to mark routes inserted in the RIB with a process ID of some sort. This would come naturally if the entire IRS idea were to put an "off board routing process" on the box that interacts with existing on board processes (see #1 above), but as the draft stands, there's no way to insert a process id into the RIB. This is crucial for redistribution, and I suspect redistribution is going to be a huge problem to address in the long term, since the routes injected by IRS, however they're injected, will need to interact with the dynamic protocols running on the box. [Sue] See our work on Route servers (1990-1995) and current work - for an example. This is what I mentioned above. 3. There are a ton of other possible use cases, if more are needed/wanted to support the reasoning behind the draft. Choosing the optimal exit from any given edge (OER in cisco lingo), a superset of Flowspec to combat DDoS is another (mentioned tangentially, but not as a use case), live/live is another (packet replication and choosing the best of two identical streams) --and there are others... Some of these might actually be more interesting use cases than are currently described in the draft. More if I get the chance to reread it in a little more depth later. Sue: Use cases are key. The clarity of the use cases will guide us. Please send USE cases. Russ -- <>< riwhite@verisign.com russw@riw.us _______________________________________________ irs-discuss mailing list irs-discuss@ietf.org https://www.ietf.org/mailman/listinfo/irs-discuss
- [irs-discuss] Thoughts on draft-ward-irs-framework Russ White
- Re: [irs-discuss] Thoughts on draft-ward-irs-fram… Alia Atlas
- Re: [irs-discuss] Thoughts on draft-ward-irs-fram… Susan Hares
- Re: [irs-discuss] Thoughts on draft-ward-irs-fram… Russ White
- Re: [irs-discuss] Thoughts on draft-ward-irs-fram… Russ White
- Re: [irs-discuss] Thoughts on draft-ward-irs-fram… Alia Atlas
- Re: [irs-discuss] Thoughts on draft-ward-irs-fram… Thomas Nadeau
- [irs-discuss] Clarification questions ... Robert Raszuk
- Re: [irs-discuss] Clarification questions ... Thomas Nadeau