Re: Destination-IP-Origin-AS Filter for BGP Flow Specification

Hi Jeffrey,

	Flowspec is designed for security protection, but current usage is not limited to security protection, 
    but also to optimize traffic. Using Flowspec to optimize traffic is safer and more reliable than send routes to router.

    Our scenario here is for optimize traffic. The actions here are all performed on the routers. You need to perform a FIB lookup to get dest-as.

    This does violate some of the current rules and introduces a certain performance penalty,
    but it can reduce the demand for Flowspec entry space, so you can use this rule in the appropriate scenario.

Regards, 
Haibo

-----Original Message-----
From: Jeffrey Haas [mailto:[email protected]] 
Sent: Friday, November 8, 2019 1:38 AM
To: Wanghaibo (Rainsword) <[email protected]>
Cc: Robert Raszuk <[email protected]>; [email protected]; Zhuangshunwan <[email protected]>; idr@ietf. org <[email protected]>
Subject: Re: [Idr] Destination-IP-Origin-AS Filter for BGP Flow Specification

Haibo,

On Tue, Nov 05, 2019 at 08:11:12AM +0000, Wanghaibo (Rainsword) wrote:
> PS: Netflow is already supporting statistical traffic based on Dest-IP-Origin-AS, it already download Dest-IP-Origin-AS to FIB entry, this prosess can be reused.

>From a forwarding perspective, this is the detail that bothers me.

Flowspec right now is currently independent of FIB state.  It functions on the firewall layer, which is typically implemented prior to FIB.

What this feature implies is something roughly like:
Packet comes in, hits rule to check dst-as.
dst-as lookup needs to happen as one of:
- communicate to BGP routing process. (not likely to scale)
- trigger a FIB lookup, check returned dst-as.  Violates pipelining in many
  architectures.
- Have the entire FIB's dst-as-map pushed into memory for firewall,
  implement as a longest-match lookup on that collection.

-- Jeff

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