On Wed, Jan 31, 2018 at 11:58:19AM +0000, Job Snijders wrote: > On Wed, Jan 31, 2018 at 09:41:55AM +0000, Stuart Henderson wrote: > > Question is why the prefixlen is set this way... > > [snip] > > Type Code: MP_UNREACH_NLRI (15) > > Length: 19 > > Address family identifier (AFI): IPv4 (1) > > Subsequent address family identifier (SAFI): Labeled VPN Unicast (128) > > Withdrawn routes (16 bytes) > > BGP Prefix > > > Prefix Length: 120 > > Label Stack: 0 (withdrawn) > > Route Distinguisher: 56028:130 > > MP Unreach NLRI IPv4 prefix: 100.64.0.42 > > For prefix 100.64.0.42, you'd think the only valid mask is 31 or 32. > Perhaps this is a bug in IOS XE?
I went off the wrong track. I think this is the encoding described in https://tools.ietf.org/html/rfc8277#page-12 Kind regards, Job
