© 2009 Cisco Systems, Inc. All rights reserved. Cisco Public Presentation_ID 1 BGP Prefix Origin Validation State Extended Community draft-pmohapat-sidr-origin-validation-signaling-00 Pradosh Mohapatra, Keyur Patel, John Scudder, David Ward, Randy Bush IETF 78, July 2010, Maastricht, Netherlands

2 Issue: IBGP hides path validation state iBGP Full Mesh p p p valid invalid unknown which do i choose?

3 Issue: Unknown Path validation state beats Valid Path validation state  r1.iad#sh ip bgp  BGP routing table entry for /24, version  Paths: (2 available, best #1, table default)  Not advertised to any peer   (metric 1) from ( )  Origin IGP, metric 51, localpref 100, valid, internal, best  Community: 2914: : : :380   from ( )  Origin IGP, metric 0, localpref 100, valid, external  Community: 3927:380  Sovc state valid

4 Solutions:  Use Local Policies to tweak BGP parameters that influence bgp bestpath decisions based on path validation state  Define a new Extended Community to carry path validation state of announced paths

5 Solution: Path Validation State Extended community  Prefix validation marking done only for EBGP updates  New Opaque Extended Community defined to carry the marking across IBGP mesh so that other speakers take the correct/consistent best path decision  Sender sends the validation state in an opaque extended community (non-transitive)  Receiver translates the received extended community into appropriate path validation state before bgp inbound policy processing and bgp bestpath processing

6 Solution: Path Validation State Extended community Format  Validation State BGP_PFX_STATE_VALID = 0 BGP_PFX_STATE_NOTFOUND =1 BGP_PFX_STATE_INVALID = | 0x43 | TBD | Reserved | | Reserved |validationstate|

7 Questions?