Hi, So is junos and ios really coded to carve up a separate FIB tables each with it's own table preamble and stuff + adjacency table for each vrf?
As I believe it's possible to have a common FIB with some sort of a marker asociated with each table entry -describing the vrf participation Than wen you come out an interface asociated with a particular marker (vrf) the lookup would be done only on a subset of prefixes with the marker matching the one asociated with the interface -though I'm not sure whether this would work with the common adjacency table and it's l2 overrides Now in dcef mode With a separate FIB+Adjacency tables per vrf You could copy only subset of FIB and Adjacency tables to the linecard based on which vrfs the interfaces on the particular line-card are asociated with -to save up some memory (than a proces would be needed to request FIB resend from the RP when interface on a line-card would be asociated with a new vrf) adam -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Gert Doering Sent: Tuesday, September 27, 2011 9:58 AM To: Derick Winkworth Cc: [email protected]; [email protected] Subject: Re: [c-nsp] general question on VRFs and FIBs... Hi, On Mon, Sep 26, 2011 at 01:18:05PM -0700, Derick Winkworth wrote: > I'm trying to find an archived discussion or presentation discussing > why exactly the industry generally settled on having a separate > FIB table for each VRF vs having one FIB table with a column that > identifies the VRF instance? I'm not finding it, but I'm guessing > its because of performance issues? Lookup would fail for overlapping address space if you lookup "address first, VRF second". How do you find the right entry if you have 10.0.0.0/8 vrf red 10.0.0.0/16 vrf green 10.0.1.0/24 vrf blue and try to look up 10.0.0.1 in vrf red? You'll find the /24 entry, which is tagged "vrf blue". Alternatively, you'd need to explode the /8 entry for vrf red if *another* VRF adds a more specific for that /8. gert -- USENET is *not* the non-clickable part of WWW! //www.muc.de/~gert/ Gert Doering - Munich, Germany [email protected] fax: +49-89-35655025 [email protected] _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
