Re: [irs-discuss] irs-discuss Digest, Vol 2, Issue 3

[Thomas Nadeau <[e-mail]>]

        Apologies, they appear to not be there.  In the meantime, you can find
them here:

http://www.lucidvision.com/draft-ward-irs-framework-00d.ppt


On 8/2/12 11:23 AM, "Thomas Nadeau" <[e-mail]> wrote:

>They are at the bottom of the routing area meeting page:
>
>https://datatracker.ietf.org/meeting/84/agenda/rtgarea/
>
>From: Ning So <[e-mail]<mailto:[e-mail]>>
>Reply-To: Ning So <[e-mail]<mailto:[e-mail]>>
>Date: Thursday, August 2, 2012 10:46 AM
>To: "[e-mail]<mailto:[e-mail]>"
><[e-mail]<mailto:[e-mail]>>
>Subject: Re: [irs-discuss] irs-discuss Digest, Vol 2, Issue 3
>
>All,
>
>Is Alia's presentation loaded anywhere?  It's not on the meeting agenda
>page.
>
>Ning
>
>From: "[e-mail]<mailto:[e-mail]>"
><[e-mail]<mailto:[e-mail]>>
>To: [e-mail]<mailto:[e-mail]>
>Sent: Thursday, August 2, 2012 1:20 AM
>Subject: irs-discuss Digest, Vol 2, Issue 3
>
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>Today's Topics:
>
>  1. Re: I-D Action: draft-ward-irs-framework-00.txt (Alia Atlas)
>  2. Re: I-D Action: draft-ward-irs-framework-00.txt (Joel M. Halpern)
>  3. Re: IRS Problem Statement Posted (Susan Hares)
>  4. Re: Thoughts on draft-ward-irs-framework (Russ White)
>Thanks!
>
>On Wed, Aug 1, 2012 at 6:54 PM, Susan Hares
><[e-mail]<mailto:[e-mail]>> wrote:
>> Alia:
>>
>> I'll try to create a bibliography of things people should read.  It
>>will be mid-next week since I'm away from my home library on the SDN
>>topic.
>>
>> Sue
>>
>> -----Original Message-----
>> From: Alia Atlas [mailto:[e-mail]<mailto:[e-mail]>]
>> Sent: Wednesday, August 01, 2012 3:51 PM
>> To: Susan Hares
>> Cc: Joel M. Halpern; [e-mail]<mailto:[e-mail]>
>> Subject: Re: [irs-discuss] I-D Action: draft-ward-irs-framework-00.txt
>>
>> Sue,
>>
>> I look forward to talking with you more off-line on the policy and
>> local-pref research and issues.  If you have suggestions on good
>> background research to read, by all means send it to the list so
>> others can get up to speed as well.
>>
>> On the atomic transaction semantics question, let's get a bit further
>> into the use-cases and framework - and then have a focused discussion.
>>  I'm not opposed to it forever or if it is necessary - just would like
>> to thoroughly analyze if it is a real requirement.
>>
>> Do others have opinions and perspective on this?
>>
>> Alia
>>
>> On Wed, Aug 1, 2012 at 1:58 PM, Susan Hares
>><[e-mail]<mailto:[e-mail]>> wrote:
>>> Alia:
>>>
>>> The hierarchical of interfaces (To routing system) is one of the areas
>>>that requires prioritization. The prioritization must be able to handle
>>>"preempt me", "after you", and "after me".
>>>
>>> It is also key to understand that irs system must handle
>>>multi-interfaces struggles at the lowest layer.  You need to look at
>>>the MIF WG (+/-) for some of the struggles of mobility.
>>>
>>> -----Original Message-----
>>> From: Alia Atlas [mailto:[e-mail]<mailto:[e-mail]>]
>>> Sent: Monday, July 30, 2012 6:33 PM
>>> To: Susan Hares
>>> Cc: Joel M. Halpern; [e-mail]<mailto:[e-mail]>
>>> Subject: Re: [irs-discuss] I-D Action: draft-ward-irs-framework-00.txt
>>>
>>> Hi Sue,
>>>
>>> On Mon, Jul 30, 2012 at 9:16 PM, Susan Hares
>>><[e-mail]<mailto:[e-mail]>> wrote:
>>>> Joel and irs-folks:
>>>>
>>>> +1 on Joel.
>>>>
>>>>  Beyond your comments, the requirement prioritization of the
>>>>interworking of these interfaces is not clearly delineated in this
>>>>work. This type of prioritization and sequencing is key to
>>>>multi-interfaces operation on the monitoring, configuration or
>>>>insertion of information into the depth.
>>>
>>> [Alia] Can you further clarify, maybe with an example, which aspect
>>> you are thinking of?  Do you mean the ability of an application to
>>> access multiple sub-interfaces?  The interaction of operations
>>> requested by differerent applications?
>>>
>>>> In addition, if you are going to do configuration with
>>>>roll-forward/roll-back - you need a transaction based processing.
>>>
>>> [Alia] I'm pretty sure that I avoided the word "transaction" in both
>>> drafts.  That was deliberate.  Of course, we can have a discussion
>>> about whether or not some form of transactions might be desirable.  I
>>> am concerned about their potentially heavy-weight nature.
>>>
>>>> Therefore, you've skipped even requiring the hard problems.
>>>
>>> [Alia] Can I optimistically pretend that means that the requirements
>>> we do have don't seem too hard?  For the responsiveness and throughput
>>> goals, I've put a stake in the ground to avoid transaction-based
>>> semantics.  Naturally, the hordes can run over that stake, if
>>> necessary.
>>>
>>> [Sue]: The requirements are necessary even if they are hard.
>>>
>>> [Alia] For the interaction between different layers of sub-interfaces,
>>> I've been assuming that we'll define the interactions between the
>>> layers based on how they are generally done.  For instance, perhaps we
>>> standardize the idea of preference value - and then the RIB can pick
>>> the best route based upon those preferences.  For interaction between
>>> different applications, I think there's a mixture of
>>> authorization/authentication to get right plus a good set of events
>>> that an application could register for.
>>>
>>> [Sue]: As someone who has lived with "local pref" in BGP for a long
>>>time, there is a bit more to unwrap in the statement.  However, it
>>>breaks down to prioritization that is pre-set by preferences.
>>>
>>> The policy issues behind the local-pref setting have been studied by
>>>the BGP policy community. This is substantial good work on this from
>>>the academic researchers, vendors, and operator. Griffins, Rexford,
>>>Bush, Feamster, ..... and lots others are much better on the theory
>>>than I am.
>>>
>>>> Is this just the -00.draft?
>>>
>>> [Alia] Certainly, I expect that we'll uncover more requirements as we
>>> go along.  As I said, some of this is initially setting parts  out of
>>> scope.
>>>
>>> ---> Scope == good.  Setting scope allows us to pick a piece of this
>>>work and standardize it for interoperability.
>>>
>>> Alia
>>>
>>>> Sue
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From:
>>>>[e-mail]<mailto:[e-mail]>
>>>>[mailto:[e-mail]<mailto:[e-mail]
>>>>g>] On Behalf Of Joel M. Halpern
>>>> Sent: Monday, July 30, 2012 3:15 PM
>>>> To: [e-mail]<mailto:[e-mail]>
>>>> Subject: Re: [irs-discuss] I-D Action: draft-ward-irs-framework-00.txt
>>>>
>>>> I am finding this document quite confusing.
>>>>
>>>> The primary confusion is that the document first says that it is about
>>>> information that can not be manipulated with existing systems, and
>>>>then
>>>> proceeds to give a list of use cases all of which can be manipulated
>>>> with existing systems at a suitable degree of abstraction.
>>>>
>>>> As a lesser confusion, the document says that "streaming" is
>>>>important,
>>>> but then describes "streaming" as "fast, interactive access."  That is
>>>> not streaming.  And depending upon what one means by interactive,
>>>>plenty
>>>> of systems provide "fest, interactive access."  I realize the document
>>>> later goes on tot talk about speed and frequency of state updates.
>>>>But
>>>> that section simply reasserts the earlier terms withotu better
>>>> description or justification.
>>>>
>>>> Yours,
>>>> Joel
>>>>
>>>> On 7/30/2012 2:08 PM,
>>>>[e-mail]<mailto:[e-mail]> wrote:
>>>>>
>>>>> A New Internet-Draft is available from the on-line Internet-Drafts
>>>>>directories.
>>>>>
>>>>>
>>>>>      Title          : Interface to the Routing System Framework
>>>>>      Author(s)      : Alia Atlas
>>>>>                            Thomas Nadeau
>>>>>                            Dave Ward
>>>>>      Filename        : draft-ward-irs-framework-00.txt
>>>>>      Pages          : 21
>>>>>      Date            : 2012-07-30
>>>>>
>>>>> Abstract:
>>>>>    This document describes a framework for a standard, programmatic
>>>>>    interface for full-duplex, streaming state transfer in and out of
>>>>>the
>>>>>    Internet's routing system.  It lists the information that might be
>>>>>    exchanged over the interface, and describes the uses of an
>>>>>interface
>>>>>    to the Internet routing system.
>>>>>
>>>> _______________________________________________
>>>> irs-discuss mailing list
>>>> [e-mail]<mailto:[e-mail]>
>>>> https://www.ietf.org/mailman/listinfo/irs-discuss
>>>> _______________________________________________
>>>> irs-discuss mailing list
>>>> [e-mail]<mailto:[e-mail]>
>>>> https://www.ietf.org/mailman/listinfo/irs-discuss
>
>With regard to transaction issues, we discussed this extensively when
>doing ForCES.  We concluded that the answer we needed was "yes and no".
>  That is, the protocol has mechanisms which can be used for
>transactional integrity, including integrity across interactions with
>multiple FEs.  However, the protocol does not require the CE to use
>those mechanisms.  In fact, if it does not even want explicit acks (the
>messages go over TCP), it can defer that until it gets to a good "please
>confirm" point.
>And in the efforts to use this later, having this range of options has
>been useful.
>
>Yours,
>Joel
>
>On 8/1/2012 6:51 PM, Alia Atlas wrote:
>> Sue,
>>
>> I look forward to talking with you more off-line on the policy and
>> local-pref research and issues.  If you have suggestions on good
>> background research to read, by all means send it to the list so
>> others can get up to speed as well.
>>
>> On the atomic transaction semantics question, let's get a bit further
>> into the use-cases and framework - and then have a focused discussion.
>>  I'm not opposed to it forever or if it is necessary - just would like
>> to thoroughly analyze if it is a real requirement.
>>
>> Do others have opinions and perspective on this?
>>
>> Alia
>>
>> On Wed, Aug 1, 2012 at 1:58 PM, Susan Hares
>><[e-mail]<mailto:[e-mail]>> wrote:
>>> Alia:
>>>
>>> The hierarchical of interfaces (To routing system) is one of the areas
>>>that requires prioritization. The prioritization must be able to handle
>>>"preempt me", "after you", and "after me".
>>>
>>> It is also key to understand that irs system must handle
>>>multi-interfaces struggles at the lowest layer.  You need to look at
>>>the MIF WG (+/-) for some of the struggles of mobility.
>>>
>>> -----Original Message-----
>>> From: Alia Atlas [mailto:[e-mail]<mailto:[e-mail]>]
>>> Sent: Monday, July 30, 2012 6:33 PM
>>> To: Susan Hares
>>> Cc: Joel M. Halpern; [e-mail]<mailto:[e-mail]>
>>> Subject: Re: [irs-discuss] I-D Action: draft-ward-irs-framework-00.txt
>>>
>>> Hi Sue,
>>>
>>> On Mon, Jul 30, 2012 at 9:16 PM, Susan Hares
>>><[e-mail]<mailto:[e-mail]>> wrote:
>>>> Joel and irs-folks:
>>>>
>>>> +1 on Joel.
>>>>
>>>>  Beyond your comments, the requirement prioritization of the
>>>>interworking of these interfaces is not clearly delineated in this
>>>>work. This type of prioritization and sequencing is key to
>>>>multi-interfaces operation on the monitoring, configuration or
>>>>insertion of information into the depth.
>>>
>>> [Alia] Can you further clarify, maybe with an example, which aspect
>>> you are thinking of?  Do you mean the ability of an application to
>>> access multiple sub-interfaces?  The interaction of operations
>>> requested by differerent applications?
>>>
>>>> In addition, if you are going to do configuration with
>>>>roll-forward/roll-back - you need a transaction based processing.
>>>
>>> [Alia] I'm pretty sure that I avoided the word "transaction" in both
>>> drafts.  That was deliberate.  Of course, we can have a discussion
>>> about whether or not some form of transactions might be desirable.  I
>>> am concerned about their potentially heavy-weight nature.
>>>
>>>> Therefore, you've skipped even requiring the hard problems.
>>>
>>> [Alia] Can I optimistically pretend that means that the requirements
>>> we do have don't seem too hard?  For the responsiveness and throughput
>>> goals, I've put a stake in the ground to avoid transaction-based
>>> semantics.  Naturally, the hordes can run over that stake, if
>>> necessary.
>>>
>>> [Sue]: The requirements are necessary even if they are hard.
>>>
>>> [Alia] For the interaction between different layers of sub-interfaces,
>>> I've been assuming that we'll define the interactions between the
>>> layers based on how they are generally done.  For instance, perhaps we
>>> standardize the idea of preference value - and then the RIB can pick
>>> the best route based upon those preferences.  For interaction between
>>> different applications, I think there's a mixture of
>>> authorization/authentication to get right plus a good set of events
>>> that an application could register for.
>>>
>>> [Sue]: As someone who has lived with "local pref" in BGP for a long
>>>time, there is a bit more to unwrap in the statement.  However, it
>>>breaks down to prioritization that is pre-set by preferences.
>>>
>>> The policy issues behind the local-pref setting have been studied by
>>>the BGP policy community. This is substantial good work on this from
>>>the academic researchers, vendors, and operator. Griffins, Rexford,
>>>Bush, Feamster, ..... and lots others are much better on the theory
>>>than I am.
>>>
>>>> Is this just the -00.draft?
>>>
>>> [Alia] Certainly, I expect that we'll uncover more requirements as we
>>> go along.  As I said, some of this is initially setting parts  out of
>>> scope.
>>>
>>> ---> Scope == good.  Setting scope allows us to pick a piece of this
>>>work and standardize it for interoperability.
>>>
>>> Alia
>>>
>>>> Sue
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From:
>>>>[e-mail]<mailto:[e-mail]>
>>>>[mailto:[e-mail]<mailto:[e-mail]
>>>>g>] On Behalf Of Joel M. Halpern
>>>> Sent: Monday, July 30, 2012 3:15 PM
>>>> To: [e-mail]<mailto:[e-mail]>
>>>> Subject: Re: [irs-discuss] I-D Action: draft-ward-irs-framework-00.txt
>>>>
>>>> I am finding this document quite confusing.
>>>>
>>>> The primary confusion is that the document first says that it is about
>>>> information that can not be manipulated with existing systems, and
>>>>then
>>>> proceeds to give a list of use cases all of which can be manipulated
>>>> with existing systems at a suitable degree of abstraction.
>>>>
>>>> As a lesser confusion, the document says that "streaming" is
>>>>important,
>>>> but then describes "streaming" as "fast, interactive access."  That is
>>>> not streaming.  And depending upon what one means by interactive,
>>>>plenty
>>>> of systems provide "fest, interactive access."  I realize the document
>>>> later goes on tot talk about speed and frequency of state updates.
>>>>But
>>>> that section simply reasserts the earlier terms withotu better
>>>> description or justification.
>>>>
>>>> Yours,
>>>> Joel
>>>>
>>>> On 7/30/2012 2:08 PM,
>>>>[e-mail]<mailto:[e-mail]> wrote:
>>>>>
>>>>> A New Internet-Draft is available from the on-line Internet-Drafts
>>>>>directories.
>>>>>
>>>>>
>>>>>        Title          : Interface to the Routing System Framework
>>>>>        Author(s)      : Alia Atlas
>>>>>                            Thomas Nadeau
>>>>>                            Dave Ward
>>>>>        Filename        : draft-ward-irs-framework-00.txt
>>>>>        Pages          : 21
>>>>>        Date            : 2012-07-30
>>>>>
>>>>> Abstract:
>>>>>      This document describes a framework for a standard, programmatic
>>>>>      interface for full-duplex, streaming state transfer in and out
>>>>>of the
>>>>>      Internet's routing system.  It lists the information that might
>>>>>be
>>>>>      exchanged over the interface, and describes the uses of an
>>>>>interface
>>>>>      to the Internet routing system.
>>>>>
>>>> _______________________________________________
>>>> irs-discuss mailing list
>>>> [e-mail]<mailto:[e-mail]>
>>>> https://www.ietf.org/mailman/listinfo/irs-discuss
>>>> _______________________________________________
>>>> irs-discuss mailing list
>>>> [e-mail]<mailto:[e-mail]>
>>>> https://www.ietf.org/mailman/listinfo/irs-discuss
>>
>
>Alia:
>
>I'm going to check with a colleague who has been doing lots of model work
>to see if he's got a better.  More later.
>
>Sue
>
>-----Original Message-----
>From: Alia Atlas [mailto:[e-mail]<mailto:[e-mail]>]
>Sent: Wednesday, August 01, 2012 3:41 PM
>To: Susan Hares
>Cc: Nitin Bahadur; James Kempf; Thomas Nadeau;
>[e-mail]<mailto:[e-mail]>
>Subject: Re: [irs-discuss] IRS Problem Statement Posted
>
>Sue,
>
>In this case, I was thinking of "translating" from a "higher
>abstraction layer" to a "lower abstraction layer".
>
>Do you have a better/different term to suggest?  I agree that clarity
>of terminology is important.
>
>Alia
>
>On Wed, Aug 1, 2012 at 2:03 PM, Susan Hares
><[e-mail]<mailto:[e-mail]>> wrote:
>> Alia:
>>
>> +1 on abstraction + filters (abstract/detail) IRS fits at the routing
>>control.
>>
>> The real question about translation is what the translation is doing.
>>Is it translating one thing to another at the same layer of abstraction
>>(e.g., Spanish/English, Ascii/ebcdic) or is it doing abstraction/detail
>>change.
>>
>> I define translation as the same layer of abstraction.  Some people
>>suggest translation = abstract/detailing.  We first need a common way to
>>talk about the difference.
>>
>> Sue
>>
>> By the way --- I'm thrilled about the pace of the discussion.
>>
>>
>> -----Original Message-----
>> From: Alia Atlas [mailto:[e-mail]<mailto:[e-mail]>]
>> Sent: Monday, July 30, 2012 6:40 PM
>> To: Susan Hares
>> Cc: Nitin Bahadur; James Kempf; Thomas Nadeau;
>>[e-mail]<mailto:[e-mail]>
>> Subject: Re: [irs-discuss] IRS Problem Statement Posted
>>
>> Sue,
>>
>> I certainly agree that we want IRS to have the ability to express
>> information at different abstraction layers and filtered on request.
>>
>> There may still be a gap between the "network OS abstractions" and IRS
>> sub-interfaces; I'd be surprised if there weren't.  IRS is to provide
>> the bottom-up control strings.
>>
>> IMHO, it's reasonable to have an entity that manages the translation.
>> For instance, one doesn't need a PCE-equiv in every application - nor
>> in every router; that might be an entity in between.
>>
>> The quantity of information is part of why explicit filtering and
>> hopefully abstraction layers should be built into the data-models.
>>
>> Alia
>>
>> On Mon, Jul 30, 2012 at 9:24 PM, Susan Hares
>><[e-mail]<mailto:[e-mail]>> wrote:
>>> Nitin:
>>>
>>> Exposing some network intelligence can either be done in detail or in
>>>some amount of summarization.
>>> If you are doing detail, you have bandwidth issues. If you are doing
>>>summarization or opacity, you are talking about layers of information.
>>>
>>> Apps need to find out what they need to get. They do not need all the
>>>details - just the fact they can get from point A to Point B (or for
>>>multi-cast B/C/D). They need to where they can go to date other
>>>applications.  They need a match-maker for the application who
>>>determine where the applications shall flow.  Now, if they are smart -
>>>like people going out to eat - they pick several ways go to eat traffic.
>>>
>>> The network orchestration then serves to be the paths to the place to
>>>eat.  This can either be distributed or centralized.
>>>
>>> If we have an Interface to routing, it need to have a two-layer
>>>concept of exposing information.
>>>
>>> Sue Hares
>>>
>>> -----Original Message-----
>>> From:
>>>[e-mail]<mailto:[e-mail]>
>>>[mailto:[e-mail]<mailto:[e-mail]
>>>>] On Behalf Of Nitin Bahadur
>>> Sent: Monday, July 30, 2012 3:33 PM
>>> To: James Kempf; Thomas Nadeau;
>>>[e-mail]<mailto:[e-mail]>
>>> Subject: Re: [irs-discuss] IRS Problem Statement Posted
>>>
>>> Hi James,
>>>
>>> This is not about splitting control plane and forwarding plane. It is
>>>about exposing network intelligence in the network elements to an
>>>external controller.
>>> And it is about allowing an external controller to use that
>>>information for enabling network-aware apps. And it is about allowing
>>>apps to influence the
>>> network element's RIB (not the FIB directly).
>>>
>>> Streaming is essential to allow for operations at scale...and avoid a
>>>request/response gated mechanism.
>>>
>>> Hope that helps.
>>>
>>> Thanks
>>> Nitin
>>>
>>> On 7/30/12 3:11 PM, "James Kempf"
>>><[e-mail]<mailto:[e-mail]>> wrote:
>>>
>>> I don't understand why streaming is specified in this draft. And I
>>>don't understand why this draft isn't put in the Forces framework.
>>>Forces is a framework explicitedly designed for device to controller
>>>communication. Its major drawback it that it is a framework with a hole
>>>in the middle, in that there are no specified devices. This draft would
>>>fill that hole.
>>>
>>> I don't think it is necessary to have a problem statement for router
>>>state update. Forces has already established that splitting the control
>>>plane into a separate device is, in some cases, an attractive design
>>>option. So I think this should be submitted to the Forces working
>>>group, or, at least, recast in the Forces framework.
>>>
>>>                jak
>>>
>>>> -----Original Message-----
>>>> From:
>>>>[e-mail]<mailto:[e-mail]>
>>>>
>>>>[mailto:[e-mail]<mailto:[e-mail]
>>>>g>] On Behalf Of Thomas Nadeau
>>>> Sent: Monday, July 30, 2012 11:18 AM
>>>> To: [e-mail]<mailto:[e-mail]>
>>>> Subject: [irs-discuss] IRS Problem Statement Posted
>>>>
>>>>
>>>>
>>>> Please review and discuss.
>>>>
>>>> Thanks,
>>>>
>>>> Tom, Alia, Ward
>>>>
>>>>
>>>> http://lucidvision.com/draft-atlas-irs-problem-statement-00.txt
>>>>
>>>>
>>>> _______________________________________________
>>>> irs-discuss mailing list
>>>> [e-mail]<mailto:[e-mail]>
>>>> https://www.ietf.org/mailman/listinfo/irs-discuss
>>>>
>>> _______________________________________________
>>> irs-discuss mailing list
>>> [e-mail]<mailto:[e-mail]>
>>> https://www.ietf.org/mailman/listinfo/irs-discuss
>>>
>>> _______________________________________________
>>> irs-discuss mailing list
>>> [e-mail]<mailto:[e-mail]>
>>> https://www.ietf.org/mailman/listinfo/irs-discuss
>>> _______________________________________________
>>> irs-discuss mailing list
>>> [e-mail]<mailto:[e-mail]>
>>> https://www.ietf.org/mailman/listinfo/irs-discuss
>
>
>> Sue: Use cases are key.  The clarity of the use cases will guide us.
>>Please send USE cases.
>
>Here are three I just threw together. We can talk about refining these
>tomorrow, if you like... My fingers got tired before my brain did. :-)
>
>Russ
>
>==
>Optimized Exit Use Case
>
>Assume you have a network where there are two possible exit points
>towards any set of destinations. The cost of using these links varies by
>time, and the quality of the links is highly variable, but not
>necessarily related to the actual load the local network is putting on
>them (in other words, these are oversubscribed links shared with other
>parallel networks or customers with unpredictable traffic patterns).
>What you'd like to do is to use the lowest cost link until the quality
>of the link reaches a specific level, and then switch to the higher cost
>link. The point at which this link switch might occur may vary based on
>time of day, because the RTO on specific traffic levels varies by the
>time of day as well.
>
>So you have a problem with multiple variables: link quality (apparently
>random from your perspective), link cost (varies by time of day), return
>on investment (varies by time of day). Combined with this you have
>multiple exit points, and you must draw traffic from an inside network
>as efficiently as possible to the best exit point, as determined by
>these various factors.
>
>The only well defined way to resolve this problem is to feed the
>variables to an off router controller, calculate the best exit point on
>some periodic basis, and then feed this information back into the
>routing table. All solutions that can solve this problem today use route
>injection into BGP, static route injection, or some other means to
>direct traffic --difficult and error prone mechanisms. All of these
>solutions also draw traffic only along links between the edge routers
>themselves to put traffic on the best possible outbound link.
>
>With IRS, the best path could be calculated using any number of custom
>written mechanisms, and the routes injected into the right places in the
>network to effect the most efficient drawing of traffic to the best exit
>point. Changes in the network environment could quickly cause traffic to
>be shifted to alternate exit points when circumstances dictate.
>
>==
>Denial of Service
>
>FlowSpec is designed to allow an AS to push a filter upstream, with the
>ultimate goal being to block the source of DDoS and other attacks as
>close to the origin of those attacks as possible. There are some
>situations, however, where you would prefer to block an attack at all
>edges, or throughout an entire local network. For instance, you might
>want to block the forwarding of traffic within your network while you
>are pushing FlowSpec updates upstream to block the traffic closer to the
>source, or you might be dealing with an attack originating from multiple
>points within your own network.
>
>While these responses are possible with standard routing, there is a
>strong case to be made that routing information should not be mixed with
>security response information within the routing domain (within an AS).
>Mixing these two types of information can make network management more
>difficult, and slow down the repair of a network during large scale
>failures. It would be simpler to have a single controller in a network
>tied to the various attack detection mechanisms that could directly
>install the correct routing information to pull all attack traffic to a
>central location, or to simply route the traffic to a null interface.
>
>An related use is that of pulling unknown traffic through specific
>devices for analysis. A network operator may not want to drive all
>traffic through traffic analysis devices simply because of cost and
>quality of service degredation. A network operator could use IRS to
>directly modify the routing tables on devices in the path of unknown or
>possibly dangerous flows so this traffic is pulled through the correct
>monitoring and analysis devices.
>
>==
>Remote Service Routing
>
>In hub and spoke overlay networks, there is always an issue with
>balancing between the information held in the spoke routing table,
>optimal routing through the network underlying the overlay, and
>mobility. Most solutions in this space use some form of centralized
>route server that acts as a directory of all reachable destinations and
>next hops, a protocol by which spoke devices and this route server
>communicate, and caches at the remote sites.
>
>An IRS solution would use the same elements, but with a different
>control plane. Remote sites would register (or advertise through some
>standard routing protocol, such as BGP), the reachable destinations at
>each site, along with the address of the router (or other device) used
>to reach that destination. These would, as always, be stored in a route
>server (or several redundant route servers) at a central location.
>
>When a remote site sends a set of packets to the central location that
>are eventually destined to some other remote site, the central location
>can forward this traffic, but at the same time simply directly insert
>the correct routing information into the remote site's routing table. If
>the location of the destination changes, the route server can directly
>modify the routing information at the remote site as needed.
>An interesting aspect of this solution is that no new and specialized
>protocols are needed between the remote sites and the centralized route
>server(s). Normal routing protocols can be used to notify the
>centralized route server(s) of modifications in reachability
>information, and the route server(s) can respond as needed, based on
>local algorithms optimized for a particular application or network. For
>instance, short lived flows might be allowed to simply pass through the
>hub site with no reaction, while longer lived flows might warrant a
>specific route to be installed in the remote router. Algorithms can also
>be developed that would optimize traffic flow through the overlay, and
>also to remove routing entries from remote devices when they are no
>longer needed based on far greater intelligence than simple non-use for
>some period of time.
>
>==
>
>
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