Re: [Idr] Regarding draft-vandevelde-idr-flowspec-path-redirect//答复: IDR interim (10/26/2015) 10:00am - 11:30am ET update

["VAN DE VELDE, Gunter (Gunter)" <[e-mail]>]

Robert,

Yeah, BGP is indeed p2mp relationship… This is important to keep in mind, and that it is exactly why PATH-ID makes sense.

With 32-bit you have 2^32 and with 128-bit you have 2^128 unique identifiers. That is quite a lot and will serve redirect policies in most networks I would assume.

In manual setup it is simple for a single PE:

  *   Preconfigure the PE with a tunnel and map it to a given unique PATH_ID
  *   This tunnel now exists, however it is not used
  *    Now the controller (i.e. vRR) sends a flow spec rule to identify the traffic using this tunnel and steers traffic into this tunnel

When you have multiple PE’s using a single redirect service:

  *   Same setup as above, but on each PE the redirect tunnel will share the unique PATH_ID reflecting the redirect tunnel service
  *   (there is no relationship that the destination is the same… just the redirect service is the same)

When you have 5000 of these Redirect services planned:

  *   Manual config will make you go crazy very soon
  *   The above can be 100% orchestrated or a mix of manual/orchestrated could be used

The benefit of redirect-to-PATH_ID facilitates that network redirect service it decoupled from the tunnel creation/characteristics. hence the setup of a mp2p tunnel is beyond the scope the path_ID redirect draft if that happens to be the redirect service you had in mind.

G/


From: <[e-mail]<mailto:[e-mail]>> on behalf of Robert Raszuk <[e-mail]<mailto:[e-mail]>>
Date: Monday 26 October 2015 at 17:41
To: Gunter Van de Velde <[e-mail]<mailto:[e-mail]>>
Cc: Lizhenbin <[e-mail]<mailto:[e-mail]>>, Susan Hares <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: Re: [Idr] Regarding draft-vandevelde-idr-flowspec-path-redirect//答复: IDR interim (10/26/2015) 10:00am - 11:30am ET update

Hi Gunter,

Let's observe that BGP signalling is p2mp.

Now let's also notice that as you correctly state TE tunnels are rather custom crafted p2p entities.

Then natural question comes to mind ...

How good does it serve to signal identical PATH_ID to all head ends for a given flow while what you need to do is to map it rather uniquely in the network ?

While in theory one could construct number of mp2p TE forwarding graphs each with identical PATH_ID on a per flow basis I bet in practice this was not the application you had in mind as its opex would be rather high as compared to real practical usefulness :)

Side question ... How are you going to provision mp2p TE ? Are you going to dust-off some proposals for it from the past ? Example: https://tools.ietf.org/html/draft-yasukawa-mpls-mp2p-rsvpte-06

Or was perhaps your plan to provision number of p2p TE tunnels from PCE/Controller with the identical PATH_IDs ?

Cheers,
R.


On Mon, Oct 26, 2015 at 5:26 PM, VAN DE VELDE, Gunter (Gunter) <[e-mail]<mailto:[e-mail]>> wrote:
Hi Robin,

Thanks for your note.

A tunnel is not always going over shortest path. Some tunnels are TE tunnels and are deliberately not going over a shortest path. This is something that draft-rosen-idr-tunnel-encaps-00 will not help to signal because the tunnel-encap attribute indicates tunnel parameters used by the tail-end.

If a redirect tunnel represents a particular redirect/steering service (better delay, less packet loss, non-SRLG, more BW, etc…) then it does become rather complex for BGP as signalling technology because a tunnel relationship is a unique between 'a headend' and ‘a tailed' device. It seems better to leave tunnel-setup to dedicated tunnel-setup mechanisms like PCEP, SR, etc….

The draft redirect-to-PATH_ID is providing the means to signal a flow-based redirect/steering service, and have each recipient router identify using local recursion for the PATH_IDs the corresponding tunnels/redirect-info. This allows for tunnel setup complexity to be taken away from BGP, while at the same time BGP is doing what it is very good at doing: "It signals a policy” in reliable fashion.

Kind Regards,
G/



From:  Idr <[e-mail]<mailto:[e-mail]>> on behalf of Lizhenbin <[e-mail]<mailto:[e-mail]>>
Date: Monday 26 October 2015 at 16:51
To: Susan Hares <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Cc: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: [Idr] Regarding draft-vandevelde-idr-flowspec-path-redirect//答复: IDR interim (10/26/2015) 10:00am - 11:30am ET update

Hi Gunter,
Regarding your presentation, I have following comments:
Do you mean draft-hao-idr-flowspec-redirect-tunnel is to signal tunnel setup info? draft-hao-idr-flowspec-redirect-tunnel is to steer traffic to the tunnel instead of signal tunnel setup.
I am not sure if the reuse of draft-rosen-idr-tunnel-encaps-00 in the draft make you confused? We just hope to  just reuses the attributes of to specify the tunnel type to help steering
the traffic to tunnel. If this is not a good way, maybe we can define new attributes.


Best Regards,
Robin





发件人: Idr [mailto:[e-mail]] 代表 Susan Hares
发送时间: 2015年10月25日 22:07
收件人: [e-mail]<mailto:[e-mail]>
抄送: [e-mail]<mailto:[e-mail]>
主题: [Idr] IDR interim (10/26/2015) 10:00am - 11:30am ET update

IDR WG members:

Below is an updated agenda for the IDR interim on 10/26/2015.

Sue

------------
IDR interim October 26, 2015
10:00 - 11:30am

1. Chair's slides [10:00-10:05]

1. draft-litkowski-idr-flowspec-interfaceset-01.txt
   speaker: Stephane Litowski
   Time: 10:05-10:15
   https://datatracker.ietf.org/doc/draft-litkowski-idr-flowspec-interfaceset/

2. draft-hao-idr-flowspec-redirect-tunnel-00
   Speaker: Weiguo Hao
   Time: 10:15 - 10:25
   http://datatracker.ietf.org/doc/draft-hao-idr-flowspec-redirect-tunnel/


3. draft-vandevelde-idr-flowspec-path-redirect
   Speaker: Gunter Van De Velde
   Time: 10:25- 10:35
   http://datatracker.ietf.org/doc/draft-vandevelde-idr-flowspec-path-redirect/


4. Draft Name: draft-hao-idr-flowspec-nvo3-02
   Speaker: Weiguo Hao
   Duration: 10:35-10:40
   http://datatracker.ietf.org/doc/draft-hao-idr-flowspec-nvo3/


5. draft-liang-idr-bgp-flowspec-label-01.txt.
   Speaker:
   Duration: 10:40-10:45
  http://datatracker.ietf.org/doc/draft-liang-idr-bgp-flowspec-label/

6. draft-liang-idr-bgp-flowspec-time
   presenter: Jianjie You
   time: 10:45-10:55
   http://datatracker.ietf.org/doc/draft-liang-idr-bgp-flowspec-time/

7. Draft Name: draft-li-idr-mpls-path-programming-02
   Speaker: Zhenbin Li
   Duration: 10:55-11:05
   http://datatracker.ietf.org/doc/draft-li-idr-mpls-path-programming/

7. Draft Name: draft-li-idr-flowspec-rpd-01
   Speaker: Shunwan Zhuang
   Duration: 11:05 - 11:15
   http://datatracker.ietf.org/doc/draft-li-idr-flowspec-rpd/

8.  Discussion of Flowspec drafts
    11:15 - 11:30am

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